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LUBRICATION AND MAINTENANCE 0 - 1
LUBRICATION AND MAINTENANCE
CHASSIS AND BODY COMPONENTS
DRIVETRAIN
ENGINE MAINTENANCE
CONTENTS page
. . . . . . . 30
. . . . . . . . . . . . . . . . . . . . . . . . . . . 22
. . . . . . . . . . . . . . . . . . 13
page
GENERAL INFORMATION
. . . . . . . . . . . . . . . . . . 1
JUMP STARTING, HOISTING AND TOWING
. . 7
MAINTENANCE SCHEDULES
. . . . . . . . . . . . . . . 5
GENERAL INFORMATION
INDEX
page
Classification of Lubricants
. . . . . . . . . . . . . . . . . . 2
Components Requiring No Lubrication
Fluid Capacities
. . . . . . . . . . . . . . . . . . . . . . . . . . 4
Fuel Requirements
. . . . . . . . . . . . . . . . . . . . . . . . 2
page
Introduction
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Recommended Lubricant and Replacement Parts
Routine Service
. . . . . . . . . . . . . . . . . . . . . . . . . . . 2
INTRODUCTION
Jeep t lubrication and maintenance is divided into required and recommended service tasks.
The recommendations and procedures listed in this group are intended for Jeep t
Dealer Service Personnel.
Because conditions vary, it is necessary to schedule service tasks according to a time interval as well as a distance interval.
It is the owner’s responsibility to have vehicle serviced. Owner is to pay for labor and necessary parts that are not covered by the warranty.
Additional lubrication and maintenance information is listed in the Owner’s Manual, which is included with the vehicle.
SEVERE DRIVING CONDITIONS
When a vehicle is subjected to a severe driving condition, time between recommended maintenance should be decreased.
Refer to Engine Maintenance for the engine oil and filter maintenance interval when involved with a severe driving condition.
A severe driving condition is defined as either:
• frequent short trip driving less than 24 km (15 miles);
• frequent driving in a dusty environment;
• trailer towing;
• extensive engine idling;
• sustained high-speed operation;
• desert operation;
• frequent starting and stopping;
• cold-climate operation;
• off-road driving; or
• commercial service.
To service a Jeep t vehicle for a severe driving condition, change all the lubricating fluids and lubricate:
• the body components,
• all the driveline coupling joints, and
• the steering linkage more often than for a normal driving condition to prevent excessive wear of the components.
DUSTY AREAS
Driving in an area with dust-filled air increases the risk of particles entering the engine and crankcase.
With this type of severe driving condition, attention should be given to the engine and crankcase components.
OFF-ROAD (4WD) OPERATION
After completion of off-road (4WD) operation, the underside of the vehicle should be thoroughly inspected. Examine threaded fasteners for looseness.
HARSH SURFACE ENVIRONMENTS
After vehicle operation in a harsh surface environment, the following components should be inspected and cleaned as soon as possible:
• brake drums,
• brake linings,
• front wheel bearings (2WD vehicles only), and
• axle coupling joints.
This will prevent wear and/or unpredictable brake action.
0 - 2 LUBRICATION AND MAINTENANCE
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ROUTINE SERVICE
The following routine vehicle service is highly recommended on a monthly basis.
TIRES—Inspect the tires for unusual wear/damage and determine if the inflation pressure is acceptable for the vehicle load.
BATTERY—Inspect and clean the terminals.
Tighten the terminals, if necessary.
FLUIDS—Determine if the coolant, brake fluid, power steering, automatic transmission, and clutch fluid level are acceptable. Add fluid, if necessary.
LIGHTS/ELECTRICAL—Test all the electrically operated systems in the vehicle for proper operation.
It is also recommended that the engine oil level and the windshield washer fluid level be determined (and corrected) during each fuel fill-up.
FUEL REQUIREMENTS
All Jeep t engines require the use of unleaded gasoline. In addition, the fuel must have a minimum octane rating of 87.
CAUTION: UNLEADED FUEL ONLY must be used in vehicles equipped with a catalyst emission control system. All vehicles have reminders printed on the instrument panel (Fig. 1) and on the fuel filler door
(Fig. 2). Vehicles also have fuel filler tubes that are designed to accept only the small-diameter unleaded gasoline nozzles. It is illegal to defeat the design of an unleaded fuel filler tube.
Fig. 2 Unleaded Fuel Only Reminder—Fuel Filler
Door
• American Petroleum Institute (API), and
• National Lubricating Grease Institute (NLGI).
ENGINE OIL
SAE VISCOSITY GRADE
An SAE viscosity grade is used to specify viscosity of engine oil. SAE 30 specifies a single viscosity engine oil. Engine oils also have multiple viscosities
(Fig. 3).
CLASSIFICATION OF LUBRICANTS
Lubricating fluids and chassis component lubricants are classified and graded according to standards recommended by the:
• Society of Automotive Engineers (SAE),
Fig. 1 Unleaded Fuel Only Reminders—Fuel Gauge
Fig. 3 SAE Oil Viscosity Grade & API Service Grade
The viscosity grade of an oil is an indicator of its thickness or flow capability. The lower the number, the better the flow. The second viscosity grade number (without a W suffix) is the warm/hot-temperature viscosity. The viscosity increases with engine temperature. With a single viscosity grade, the oil viscosity is valid only for one narrow temperature range.
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LUBRICATION AND MAINTENANCE 0 - 3
Above that temperature range the viscosity will decrease, and below that range the viscosity will increase.
An engine oil with an SAE 5W-30 viscosity grade provides good flow capability for fast cold weather engine starts. The viscosity will then increase with engine temperature to provide good high-temperature engine lubrication.
API SERVICE GRADE
The API Service Grade specifies the type of engine/ operating conditions for which the oil is intended.
The API Service Grade specifications also apply to energy conserving engine oils (Fig. 3). The API certification mark is also used indicating that the oil is certified to meet the most critical requirements established by the manufacturer (Fig. 4).
CHASSIS COMPONENT AND WHEEL BEARING
LUBRICANTS
The chassis component and wheel bearing lubricants are identified by the NLGI Certification Symbol (Fig. 5).
Fig. 4 The API Engine Oil Certification Mark
For maximum protection, use API Service Grade
SG, SG/CD or SG/CE engine oil in Jeep t engines.
GEAR LUBRICANTS
A dual SAE viscosity grade is also used to specify the viscosity of multipurpose gear lubricants.
The API lubrication quality grade designation identifies gear lubricants in terms of recommended usage.
Fig. 5 NLGI Lubricant Certification/Identification
Symbol
The letter G indicates wheel bearing lubricant and the letter L indicates chassis lubricant. When the letters are combined the lubricant can be used for dual applications. The suffix letters C and B indicates quality level of the lubricant. Use only lubricants that display the NLGI Certification Symbol.
RECOMMENDED LUBRICANT AND REPLACEMENT
PARTS
Jeep t vehicles are engineered to provide many years of dependable operation. When necessary, MO-
PAR brand lubricants and genuine replacement
parts are highly recommended.
COMPONENTS REQUIRING NO LUBRICATION
There are many components that should not be lubricated. The components that should not be lubricated are:
• air pumps;
• generator bearings;
• drive belts;
• drive belt idler pulleys;
• rubber bushings;
• starter motor bearings;
• suspension strut bearings;
• throttle control cables;
• throttle linkage ball joints; and
• water pump bearings.
0 - 4 LUBRICATION AND MAINTENANCE
FLUID CAPACITIES
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LUBRICATION AND MAINTENANCE 0 - 5
INTRODUCTION
Chrysler Corporation has compiled recommended lubrication and maintenance schedules and procedures to help reduce premature wear or failure over a broad range of operating conditions.
SEVERE SERVICE MAINTENANCE
If the vehicle is involved with a severe driving condition, after each 4 800-km (3,000-miles)/3-month interval. A severe driving condition includes:
• frequent short trip driving less than 24 km (15 miles);
• frequent driving in a dusty environment;
• trailer towing;
• extensive engine idling;
• sustained high-speed operation;
• desert operation;
• frequent starting and stopping;
• cold-climate operation;
• off-road driving; or
• commercial service.
MAINTENANCE SCHEDULES
MAINTENANCE SCHEDULES
AT EACH STOP FOR FUEL
• Check engine oil level, add as required.
• Check windshield washer solvent and add if required.
• Check fluid level in battery.
• Rotate Tires.
22,500 MILES (36 000 KM) OR AT 18 MONTHS
• Check engine coolant level, hoses and clamps.
•
Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
•
Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Rotate Tires.
30,000 MILES (48 000 KM) OR AT 24 MONTHS
• Replace air cleaner filter.
• Replace spark plugs.
• Adjust drive belt.
•
Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Check fluid level in battery.
•
Drain and refill automatic transmission.
• Drain and refill transfer case.
• Rotate Tires.
ONCE A MONTH
• Check tire pressure and look for unusual wear or damage.
• Inspect battery and clean and tighten terminals as required.
• Check electrolyte level and add water as needed.
•
Check fluid levels of coolant reservoir, power steering and transmission and add as needed.
•
Check all lights and all other electrical items for correct operation.
•
Check rubber seals on each side of the radiator for proper fit.
37,500 MILES (60 000 KM) OR AT 30 MONTHS
• Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
•
Lubricate propeller shaft universal joints.
•
Drain and refill manual transmission.
•
Rotate Tires.
7,500 MILES (12 000 KM) OR AT 6 MONTHS
• Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Rotate Tires.
15,000 MILES (24 000 KM) OR AT 12 MONTHS
• Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
45,000 MILES (72 500 KM) OR AT 36 MONTHS
• Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Check fluid level in battery.
• Rotate Tires.
52,500 MILES (84 500 KM) OR AT 42 MONTHS
• Flush and replace engine coolant.
• Check engine coolant system hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Rotate Tires.
0 - 6 LUBRICATION AND MAINTENANCE
60,000 MILES (96 500 KM) OR AT 48 MONTHS.
• Replace air cleaner filter.
• Replace distributor cap and rotor.
• Replace ignition wires.
• Replace spark plugs.
• Adjust or replace drive belt.
•
Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
•
Check exhaust system.
• Replace fuel filter (not required for Calif. vehicles).
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
•
Check fluid level in battery.
• Drain and refill automatic transmission.
• Drain and refill transfer case.
• Rotate Tires.
67,500 MILES (108 500 KM) OR AT 54
MONTHS
• Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Rotate Tires.
75,000 MILES (120 500 KM) OR AT 60
MONTHS
• Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
•
Lubricate propeller shaft universal joints.
•
Drain and refill manual transmission.
•
Rotate Tires.
82,500 MILES (133 000 KM) OR AT 66
MONTHS
• Flush and replace engine coolant.
• Check engine coolant system, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Rotate Tires.
90,000 MILES (145 000 KM) OR AT 72
MONTHS
• Replace air cleaner filter.
• Replace spark plugs.
• Adjust drive belt.
• Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
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• Check exhaust system.
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Check fluid level in battery.
• Drain and refill automatic transmission.
• Drain and refill transfer case.
•
Rotate Tires.
97,500 MILES (157 000 KM) OR AT 78
MONTHS
•
Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Rotate Tires.
105,000 MILES (169 000 KM) OR AT 84
MONTHS
• Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
•
Lubricate propeller shaft universal joints.
• Rotate Tires.
112,500 MILES (181 000 KM) OR AT 90
MONTHS
• Flush and replace engine coolant.
• Check engine coolant system hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Lubricate steering linkage (4x4 models).
•
Lubricate propeller shaft universal joints.
• Rotate Tires.
120,000 MILES (193 000 KM) OR AT 96
MONTHS
• Replace air cleaner filter.
• Replace distributor cap and rotor.
• Replace ignition wires.
• Replace spark plugs.
• Adjust or replace drive belt.
• Check engine coolant level, hoses and clamps.
• Change engine oil.
• Replace engine oil filter.
• Check exhaust system.
• Replace fuel filter (not required for Calif. vehicles).
• Lubricate steering linkage (4x4 models).
• Lubricate propeller shaft universal joints.
• Check fluid level in battery.
• Drain and refill automatic transmission.
• Drain and refill transfer case.
• Rotate Tires.
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LUBRICATION AND MAINTENANCE 0 - 7
JUMP STARTING, HOISTING AND TOWING
JUMP STARTING
WARNING: DO NOT ATTEMPT TO PUSH OR TOW A
VEHICLE TO START THE ENGINE. UNBURNED
FUEL COULD ENTER THE EXHAUST CATALYTIC
CONVERTER AND IGNITE AFTER THE ENGINE IS
STARTED. THIS COULD CAUSE THE CONVERTER
TO OVERHEAT AND RUPTURE.
BOOSTER BATTERY
WARNING: TO PREVENT PERSONAL INJURY OR
CLOTHING DAMAGE, DO NOT ALLOW BATTERY
(ACID) TO CONTACT EYES, SKIN OR CLOTHING.
DO NOT LEAN OVER A BATTERY WHEN CON-
NECTING JUMPER CABLES. DO NOT ALLOW THE
POSITIVE AND NEGATIVE CABLE CONNECTOR
CLAMPS TO CONTACT EACH OTHER. KEEP OPEN
FLAMES AND SPARKS AWAY FROM THE BATTERY
VENT HOLES. ALWAYS WEAR EYE PROTECTION
WHEN INVOLVED WITH BATTERIES.
If it is necessary to use a booster battery and jumper cables to start an engine use the following procedure.
(1) Engage the parking brake and shift the automatic transmission to PARK, manual transmission shift to NEUTRAL.
(2) Turn off all lights, the heater-A/C blower motor, and all other electrical loads.
WARNING: WHEN THE AIR TEMPERATURE IS BE-
LOW THE FREEZING POINT (0°C OR 32°F), THE
ACID IN A DISCHARGED VEHICLE BATTERY CAN
FREEZE. DO NOT ATTEMPT TO JUMP START AN
ENGINE BEFORE DETERMINING THE CONDITION
OF THE BATTERY.
(3) Inspect the general condition of the battery.
CAUTION: Do not permit metal surfaces on vehicles to contact because this could establish ground continuity between vehicle bodies.
(4) Attach a red cable connector clamp to the positive (+) terminal on the booster battery. Connect the other red cable connector clamp to the positive
(+) terminal on the discharged battery (Fig. 6).
CAUTION: Use care to avoid allowing the positive
(+) and negative (-) cable clamps to contact each other. DO NOT lean over the battery when connecting the cable clamps.
Fig. 6 Jumper Cable Connections
WARNING: DO NOT CONNECT A JUMPER CABLE
CONNECTOR CLAMP TO THE NEGATIVE POST OF
THE DISCHARGED BATTERY.
(5) Connect a black jumper cable connector clamp to the negative (-) terminal on the booster battery.
Connect the other black jumper cable connector clamp to a good ground.
(6) Start the engine.
WARNING: THE USE OF ANY JUMPER CABLE DIS-
CONNECTION PROCEDURE OTHER THAN THAT
DESCRIBED BELOW COULD RESULT IN:
• PERSONAL INJURY CAUSED BY BATTERY
ELECTROLYTE SQUIRTING FROM THE BATTERY
VENTS.
• PERSONAL INJURY AND/OR PROPERTY DAM-
AGE CAUSED BY BATTERY EXPLOSION.
•
DAMAGE TO THE BOOSTER VEHICLE OR THE
DISABLED VEHICLE CHARGING SYSTEM.
(7) After the engine is started, or if the engine fails to start, the jumper cables must be disconnected in the following order:
• Black (negative) cable connector clamp from the engine ground contact.
• Black (negative) cable connector clamp from the negative terminal (-) on the booster battery.
• Red (positive) cable connector clamps from the positive (+) terminals on both batteries.
0 - 8 LUBRICATION AND MAINTENANCE
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PORTABLE STARTING UNIT
There are many types of portable starting units available for starting engines. Follow the manufacturer’s instructions when involved in any engine starting procedure.
HOISTING RECOMMENDATIONS
FLOOR JACK
When properly positioned, a floor jack can be used to lift a Jeep t vehicle. Support the vehicle in the raised position with jack stands at the front and rear ends as applicable (Fig. 7).
HOIST
A Jeep t vehicle can be lifted with a swiveling-arm type hoist; with a wheel-lift, twin-post hoist; or with a ramp-type, drive-on hoist.
When a swiveling-arm, frame-contact type hoist is used, ensure that the lifting pads are positioned at the correct sub frame rail (Fig. 7).
TOWING RECOMMENDATIONS
TOWING EQUIPMENT
A vehicle equipped with SAE approved sling-type towing equipment can be used to tow all Jeep t vehicles (Fig. 8). When it is necessary to rear-tow a vehicle, use the wheel-lift towing method with a tow dolly located under the front wheels. A vehicle with flat-bed towing equipment can also be used to transport a disabled vehicle.
Fig. 8 Tow Vehicles With Approved Equipment
A wooden crossbeam with spacer blocks could possibly be required for proper connection when using the sling-type, front-end towing method (Fig. 9).
Fig. 7 Correct Vehicle Lifting Locations—Typical
CAUTION: Do not attempt to lift a Jeep T vehicle with a floor jack positioned under:
• an axle tube,
• a body side sill,
• a steering linkage component,
• a drive shaft,
• the engine or transmission oil pan,
• the fuel tank, or
• a front suspension arm.
Use the correct sub-frame rail or frame rail lifting locations only (Fig. 7).
Fig. 9 Crossbeam & Spacer Block Construction
SAFETY PRECAUTIONS
The following safety precautions must be considered when preparing for and during a vehicle towing operation:
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LUBRICATION AND MAINTENANCE 0 - 9
• if the vehicle is damaged, secure the loose and protruding parts;
• always use a safety chain system that is independent of the lifting and towing equipment;
• do not allow any of the towing equipment to contact the disabled vehicle’s fuel tank;
• do not allow anyone to be under the disabled vehicle while it is lifted by the towing equipment;
• do not allow passengers to ride in a vehicle being towed;
• always observe all state and local laws involving warning signals, night illumination, speed, etc.
• do not attempt a towing operation that could jeopardize the safety of the operator, bystanders or other motorists;
• do not exceed a towing speed of 48 km/h (30 mph);
• avoid towing distances of more than 24 km (15 miles) whenever possible; and
• do not attach tow chains or a tow sling to a bumper, the steering linkage, the universal joints, the constant velocity (CV) joints, or a drive shaft.
CLEARANCES AND RAMP ANGLE
SURFACE CLEARANCE
The end of the disabled vehicle that is attached to the tow vehicle should be lifted a minimum of 10 cm or four inches off the surface. Inspect to ensure that the opposite end of the disabled vehicle has clearance from the surface.
RAMP ANGLE—FLAT-BED TOWING
If a vehicle with flat-bed towing equipment is used, the approach ramp angle should not exceed 15 degrees.
SLING-TYPE, FRONT-END TOWING
XJ VEHICLES
Use the following guidelines when the tow vehicle is attached to the front end of a disabled vehicle.
(1) Always tow with the front wheels lifted off the surface and turned all the way to the right.
(2) Attach a J-hook to the disabled vehicle at the left side of the axle (Fig. 10).
(3) Position the sling crossbar close to the J-hook and below the front bumper (Fig. 11).
(4) Secure a chain to the right side of vehicle by placing it over the axle shaft tube and attaching it to a structural member.
(5) Attach the safety chains to the vehicle.
2WD With Manual Or Automatic Transmission
(6) Turn the ignition switch to the OFF position to unlock the steering wheel.
(7) Shift the transmission to NEUTRAL, mark the drive shaft and axle drive pinion gear shaft yoke for installation reference. Remove the drive shaft from the vehicle.
Fig. 10 Sling-Type, Front-End Towing (XJ Front
View)
Fig. 11 Sling-Type, Front-End Towing (XJ Rear
View)
(8) Cover the exposed end of the transmission extension housing and the universal joints. Store the drive shaft in a safe place.
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Manual Transmission
(6) Turn the ignition switch to the OFF position to unlock the steering wheel.
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(7) Shift the manual transmission into a forward gear and the transfer case to NEUTRAL.
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Automatic Transmission
(6) Turn the ignition switch to the OFF position to unlock the steering wheel.
0 - 10 LUBRICATION AND MAINTENANCE
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When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(7) Shift the automatic transmission to PARK and the transfer case to NEUTRAL.
4WD, Selec-Trac (242 Full-Time 4WD Transfer
Case) And Automatic Transmission
(6) Turn the ignition switch to the OFF position to unlock the steering wheel.
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(7) Shift the automatic transmission to PARK and the transfer case to NEUTRAL.
YJ VEHICLES
Use the following guidelines when the tow vehicle is attached to the front of a disabled vehicle.
(1) Always tow with the front wheels lifted off the surface and turned all the way to the right.
CAUTION: Use tow chains with T-hooks for connecting to the disabled vehicle’s frame rails (Fig.
12). Never use J-hooks.
Fig. 13 Sling-Type, Front-End Towing (YJ Vehicles)
Command-Trac (231 Part-Time 4WD Transfer
Case) And Automatic Transmission
(6) Turn the ignition switch to the OFF position to unlock the steering wheel.
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(7) Shift the automatic transmission to PARK and the transfer case to NEUTRAL.
Fig. 12 Tow Chains & Hooks
(2) Attach the T-hooks to the slots in the front end of each frame rail (Fig. 13).
(3) Position each safety chain over the top of each front spring and inboard of each front spring shackle.
(4) Double wrap each chain.
(5) Position the sling crossbar under the front bumper.
Command-Trac (231 Part-Time 4WD Transfer
Case) And Manual Transmission
(6) Turn the ignition switch to the OFF position to unlock the steering wheel.
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(7) Shift the manual transmission to a forward gear and the transfer case to NEUTRAL.
SLING-TYPE, REAR-END TOWING
YJ VEHICLES—Use wheel-lift equipment ONLY when towing from the rear end of the vehicle is necessary.
XJ VEHICLES—Use the following guidelines when the tow vehicle is attached to the rear of the disabled vehicle.
(1) Attach J-hooks around the axle shaft tubes outboard of the shock absorber.
(2) Place the sling crossbar under and forward of the bumper.
(3) Attach safety chains around the frame rails.
2WD With Manual Or Automatic Transmission
(1) Attach J-hooks around the axle shaft tubes outboard of the shock absorber.
(2) Place the sling crossbar under and forward of the bumper.
(3) Attach safety chains around the frame rails.
(4) Turn the ignition switch to the OFF position to unlock the steering wheel.
(5) Clamp the steering wheel with the front wheels in the straight ahead position. Do not use the steering column lock as a substitute for a clamping device.
(6) Shift the transmission to NEUTRAL.
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LUBRICATION AND MAINTENANCE 0 - 11
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Manual Transmission
(1) Attach J-hooks around the axle shaft tubes outboard of the shock absorber.
(2) Place the sling crossbar under and forward of the bumper.
(3) Attach safety chains around the frame rails.
(4) Turn the ignition switch to the OFF position to unlock the steering column.
(5) Clamp the steering wheel with the front wheels in the straight ahead position. Do not use the steering column lock as a substitute for a clamping device.
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(6) Shift the transmission to a forward gear and the transfer case to NEUTRAL.
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Automatic Transmission
(1) Attach J-hooks around the axle shaft tubes outboard of the shock absorber.
(2) Place the sling crossbar under and forward of the bumper.
(3) Attach safety chains around the frame rails.
(4) Turn the ignition switch to the OFF position to unlock the steering column.
(5) Clamp the steering wheel with the front wheels in the straight ahead position. Do not use the steering column lock as a substitute for a clamping device.
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(6) Shift the transmission to PARK and the transfer case to NEUTRAL.
4WD, Selec-Trac (242 Full-Time 4WD Transfer
Case) And Automatic Transmission
(1) Attach J-hooks around the axle shaft tubes outboard of the shock absorber.
(2) Place the sling crossbar under and forward of the bumper.
(3) Attach safety chains around the frame rails.
(4) Turn the ignition switch to the OFF position to unlock the steering column.
(5) Clamp the steering wheel with the front wheels in the straight ahead position. Do not use the steering column lock as a substitute for a clamping device.
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(6) Shift the transmission to PARK and the transfer case to NEUTRAL.
TOWING WHEN IGNITION KEYS ARE NOT
AVAILABLE
VEHICLE DOORS UNLOCKED
2WD Vehicles
Either one of two methods can be used:
• tow the vehicle with the drive shaft removed (refer to Sling-Type, Front-End Towing); or
• place a tow dolly under the rear wheels (Fig. 14) and tow with the front end raised (refer to Sling-
Type, Front-End Towing).
Fig. 14 Sling-Type, Front-End Towing With Rear
Wheels On A Tow Dolly
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Manual Transmission
(1) Shift the manual transmission to a forward gear.
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(2) Shift the transfer case to NEUTRAL.
(3) The vehicle can now be towed with the front wheels raised (refer to Sling-Type, Front-End Towing).
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Automatic Transmission
(1) Check and ensure that the automatic transmission is in PARK.
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(2) Shift the transfer case to NEUTRAL.
(3) The vehicle can now be towed with the front wheels raised (refer to Sling-Type, Front-End Towing).
4WD, Selec-Trac (242 Full-Time 4WD Transfer
Case) And Automatic Transmission
(1) Check and ensure that the automatic transmission is in PARK.
0 - 12 LUBRICATION AND MAINTENANCE
J
When the transfer case is in the NEUTRAL position, both axles are disengaged from the powertrain. This allows the vehicle to be towed without removing the drive shafts.
(2) Shift the transfer case to NEUTRAL.
(3) The vehicle can now be towed with the front wheels raised (refer to Sling-Type, Front-End Towing).
4WD VEHICLES
(1) Mark the drive shafts and the axle drive pinion gear shaft yokes for installation alignment reference.
(2) Remove the drive shafts. Install a protective covering over the drive shaft U-joints/CV-joints to retain them assembled and protected.
(3) Cover the exposed ends of the transfer case.
VEHICLE DOORS LOCKED
Place a tow dolly under the rear wheels (Fig. 14) and tow with the front end raised (refer to Sling-
Type, Front-End Towing).
CAUTION: Whenever a drive shaft has been removed and installed, check the transmission fluid level of the transmission and transfer case. Driving a vehicle with low tranfer case fluid can damage the transmission and transfer case.
4WD EMERGENCY TOWING—TRANSFER CASE
NOT SHIFTED TO NEUTRAL
When a situation arises and the transfer case cannot be shifted to NEUTRAL, any of the following methods can be used to tow a 4WD vehicle.
Drive shafts not removed, place the rear wheels on a tow dolly and tow with the front end raised.
Drive shafts not removed, place the front wheels on a tow dolly and tow with the rear end raised.
Rear drive shaft removed, tow with the front end raised.
Front drive shaft removed, tow with the rear end raised.
Both drive shafts removed, tow with all four wheels on the road surface.
(1) Turn ignition key switch to the unlocked (OFF) position.
(2) Shift the transmission to the NEUTRAL position.
(3) Determine the method by which the vehicle will be towed and prepare the vehicle for towing.
(4) Connect the vehicle to the tow vehicle. Refer to the applicable procedure.
EMERGENCY TOW HOOKS
WARNING: REMAIN AT A SAFE DISTANCE FROM A
VEHICLE THAT IS BEING TOWED VIA ITS TOW
HOOKS. THE TOW STRAPS/CHAINS COULD POSSI-
BLY BREAK AND CAUSE SERIOUS INJURY.
Some Jeep t vehicles are equipped with emergency tow hooks located at the front end (Fig. 15). Some
Jeep t vehicles also have emergency tow hooks located at the rear ende. The tow hooks should be used for EMERGENCY purposes only.
CAUTION: DO NOT use emergency tow hooks for tow truck hook-up or highway towing.
FLAT TOWING (4 TIRES/WHEELS ON
SURFACE)
Tow a vehicle in this manner only when all four wheels will freely rotate. Prepare the vehicle according to the following procedures.
2WD VEHICLES
(1) Mark the drive shaft and the axle drive pinion gear shaft yoke for installation alignment reference.
(2) Remove the drive shaft. Install a protective covering over the drive shaft U-joints to retain them assembled and protected.
(3) Cover the open end of the transmission extension housing.
Fig. 15 Emergency Front Tow Hooks—XJ & YJ
Vehicles
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LUBRICATION AND MAINTENANCE 0 - 13
ENGINE MAINTENANCE
INDEX
page
Accessory Drive Belt
. . . . . . . . . . . . . . . . . . . . . . 20
Air-Conditioner Compressor/Hoses/Fittings
Battery
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Cooling System
. . . . . . . . . . . . . . . . . . . . . . . . . . 16
Crankcase Ventilation System
. . . . . . . . . . . . . . . 17
Engine Air Cleaner Filter Element
Engine Break-In
. . . . . . . . . . . . . . . . . . . . . . . . . 13
Engine Oil
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
page
Engine Oil Change and Filter Replacement
Engine Oil Filter
. . . . . . . . . . . . . . . . . . . . . . . . . 14
Engine Supports
. . . . . . . . . . . . . . . . . . . . . . . . . 20
Exhaust System
. . . . . . . . . . . . . . . . . . . . . . . . . 20
Fuel Usage Statement—Gas Engines
Ignition Cables, Distributor Cap and Rotor
Rubber and Plastic Ducts/Hoses/Tubing
Spark Plugs
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
ENGINE BREAK-IN
After first starting a new engine, allow it to idle and warm up for at least 15 seconds before shifting the transmission into a drive gear.
Drive the vehicle at:
• varying speeds less than 80 km/h (50 mph) for the first 160 km (100 miles), and
• speeds less than 88 km/h (55 mph) for the first 800 km (500 miles).
Avoid driving at full-throttle for extended periods of time. Also, avoid fast acceleration and sudden stops.
A special break-in engine oil is not required. The original oil installed in a vehicle is a quality lubricant. There is no requirement to have the oil changed or the oil filter replaced until the first scheduled maintenance interval.
The engine oil, coolant and all the other engine related fluid levels should be determined on a regular basis.
ENGINE OIL
SPECIFICATIONS
API SERVICE GRADE
For maximum engine protection during all driving conditions, install an engine oil that conforms to API
Service Grade. MOPAR Engine Oil conforms to all of these API Service Grades.
SAE VISCOSITY
SAE designated multi-viscosity grade engine oil is to protect engines. This type of engine oil can usually be installed and remain in the engine until the next scheduled oil change. Select the engine oil viscosity according to the lowest ambient air temperature expected before the next scheduled oil change (Fig.1).
Low viscosity engine oil allows easier engine starting during cold weather. SAE 5W-30 viscosity engine oil is recommended when the ambient air temperatures consistently decrease to below 10°F (-12°C).
Fig. 1 Temperature/Engine Oil Viscosity
ENERGY CONSERVING OIL
In selecting the correct API grade and SAE grade, an ENERGY CONSERVING type engine oil is also recommended.
CONTAINER IDENTIFICATION
Standard engine oil notations have been adopted for selection of engine oil. The notations are located on side of plastic bottles and on the top of engine oil cans (Fig. 2).
Fig. 2 Engine Oil Container Standard Notations
• The top, outer field contains the API Service
Grade notation for the engine oil.
0 - 14 LUBRICATION AND MAINTENANCE
• The center field contains the SAE viscosity
grade notation for the engine oil.
• The lower, outer field contains either the EN-
ERGY CONSERVING or the ENERGY CON-
SERVING II notation for the engine oil.
CAUTION: Non-detergent engine oil or straight-mineral oil must never be used to lubricate a Jeep T engine. These type of oils will not provide proper engine lubrication and can result in engine damage.
LEVEL INDICATOR (DIPSTICK)
The engine oil level indicator is located at the right rear of both 2.5L engines and 4.0L engines (Fig. 3).
Fig. 4 Engine Oil Dipstick—2.5L Engine
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Fig. 3 Engine Oil Dipstick Location—Typical
ACCEPTABLE LEVEL
To ensure proper lubrication of an engine, the engine oil must be maintained at an acceptable level.
The acceptable levels are indicated between the ADD and FULL marks on the engine oil dipstick (Figs. 4 and 5). The engine oil level should be determined at the end of each regular driving interval. The vehicle should be on a level surface. Wait for approximately five minutes after stopping the engine. Add engine oil only when the level indicated on the dipstick is at or below the ADD mark.
CAUTION: Do not overfill the engine crankcase with oil. This will cause oil aeration and result in a decrease in the engine oil pressure.
Fig. 5 Engine Oil Dipstick—4.0L Engine and anti-scuff compounds can be helpful in some instances. For example:
• with infrequent vehicle operation or short-trip only operation, or
• during engine break-in after a major engine overhaul and/or replacement piston installation.
MOPAR Engine Oil Supplement (or an equivalent product) is acceptable for the conditions listed above.
ENGINE OIL FILTER
FILTER SPECIFICATION
All Jeep t engines are equipped with a high quality full-flow, throw-away type oil filter. The same type of replacement oil filter is recommended when a replacement is required.
ADDITIVES
It is not necessary to add a special additive to engine oil for most types of vehicle operation. However, the addition of special additives containing anti-rust
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ENGINE OIL CHANGE AND FILTER REPLACEMENT
WARNING: CARE SHOULD BE TAKEN WHEN
CHANGING OIL.
PROTECTIVE CLOTHING AND
GLOVES SHOULD BE WORN.
EXPOSED SKIN
SHOULD BE WASHED WITH SOAP AND WATER TO
REMOVE ANY ENGINE OIL. DO NOT USE GASO-
LINE, THINNER, OR SOLVENTS TO REMOVE EN-
GINE OIL FROM SKIN.
LUBRICATION AND MAINTENANCE 0 - 15
REQUIRED MAINTENANCE
With normal driving conditions, engine oil and filter must be changed after each 12 000-km (7,500miles)/12-month interval. If the vehicle is involved with a severe driving condition, after each 4 800-km
(3,000-miles)/3-month interval. A severe driving condition includes:
• frequent short trip driving less than 24 km (15 miles);
• frequent driving in a dusty environment;
• trailer towing;
• extensive engine idling;
• sustained high-speed operation;
• desert operation;
• frequent starting and stopping;
• cold-climate operation;
• off-road driving; or
• commercial service.
OIL CHANGE AND FILTER REPLACEMENT
(1) Drain the engine oil from the crankcase. Wait until after the engine has attained the normal operating temperature to ensure complete drainage of oil.
(2) Install the drain-hole plug with a replacement gasket.
The oil filter should be replaced during every engine oil change.
(3) Rotate the oil filter counterclockwise to remove it from the cylinder block oil filter boss (Figs. 6 and 7).
Fig. 7 Oil Filter—4.0L Engine
(4) Clean the cylinder block oil filter boss.
(5) Apply a light coat of engine oil to the rubber seal on the replacement oil filter.
CAUTION: Do not use oil filter with metric threads.
The proper oil filter has SAE type 3/4 X 16 threads.
The use of an oil filter with metric threads can result in engine oil leaks and engine failure.
(6) Install and hand tighten the oil filter 1/2 to
3/4 of-a-turn clockwise beyond the point where the seal first contacts the cylinder block.
(7) Add engine oil in fill hole located on top of engine cylinder head cover (Fig. 8).
(8) Observe the oil level on the dipstick. Add oil, if necessary, to increase the level to the FULL mark.
Fig. 6 Oil Filter Removal—2.5L Engine
Fig. 8 Adding Engine Oil—Typical
0 - 16 LUBRICATION AND MAINTENANCE
J
CAUTION: Do not overfill the engine crankcase with oil. This will cause oil aeration and result in a decrease in the engine oil pressure.
(9) Start the engine and observe the oil pressure gauge or warning lamp. If the pressure does not increase or the warning lamp does not go out, stop the engine and determine the cause of the problem.
USED ENGINE OIL DISPOSAL
Care should be exercised when disposing used engine oil after it has been drained from a vehicle engine. Refer to the WARNING listed above.
COOLING SYSTEM
WARNING: USE EXTREME CAUTION WHEN RE-
MOVING THE RADIATOR CAP IF THE ENGINE IS
OPERATING. DO NOT PUT YOUR HANDS NEAR
THE DRIVE BELT(S), PULLEYS OR FAN BLADE. DO
NOT STAND IN A DIRECT LINE WITH THE FAN
BLADE.
RECOMMENDED MAINTENANCE
The engine coolant level should be determined at least once a month and more often during periods of hot weather. Add coolant as necessary.
COOLANT LEVEL
With the engine at normal operating temperature, observe the coolant level in the coolant recovery bot-
tle. The coolant level must be at least above the ADD mark and preferably at the FULL mark. Add coolant to the coolant recovery bottle only, if necessary.
REQUIRED MAINTENANCE
Check coolant level, and inspect condition of cooling system hoses and clamps after each 12 000-km
(7,500-miles).
Initially, coolant must be drained and cooling system flushed and filled after the first 36 months of operation. Thereafter, after each 24-months interval of vehicle operation.
RECOMMENDED MAINTENANCE
The engine cooling system should be inspected for proper operation and for component failure at least every 12 months.
WARNING: IF THE ENGINE HAS BEEN RECENTLY
OPERATED, USE EXTREME CARE WHEN REMOV-
ING THE RADIATOR CAP TO AVOID SCALDING
WITH HOT, PRESSURIZED COOLANT.
For additional information, refer to Section 7, Cooling System.
COOLANT FREEZE PROTECTION
Jeep t cooling systems contain a 50/50 mixture of anti-freeze and distilled water coolant. This is the recommended coolant mixture for most ambient temperatures. The factory-installed anti-freeze is formulated to prevent corrosion on all cooling system metal surfaces.
The degree of coolant freeze protection should be tested every 12 months. If the coolant is contaminated or rusty in appearance, cooling system should be drained and filled with a 50/50 mixture of fresh coolant. For additional information, refer to Group
7—Cooling System.
ENGINE AIR CLEANER FILTER ELEMENT
RECOMMENDED MAINTENANCE
Engine performance and fuel economy can be affected by a restricted air cleaner filter. The filter should be inspected on a regular basis for excessive air restriction.
If the filter element is saturated with oil, replace the filter element.
REQUIRED MAINTENANCE
Engine air cleaner filter must be replaced after each 48 000-km (30,000-miles).
If a vehicle is frequently operated in dusty areas, the air cleaner filter should be inspected often.
FILTER ELEMENT SERVICE/REPLACEMENT
(1) Remove the air cleaner cover from the body/ housing (Fig. 9).
(2) Remove the air cleaner filter element from the body/housing.
Fig. 9 Air Cleaner & Filter Element—2.5L and 4.0L
Engines
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LUBRICATION AND MAINTENANCE 0 - 17
CAUTION: Do not tap the filter element or immerse the filter in liquid to remove trapped particles.
(3) Clean filter element by gently blowing the trapped particles from the filter with compressed air.
Direct air in the opposite direction of normal intake air flow. Keep air nozzle at least two inches away from the filter to avoid damage to filter.
(4) If the filter has become partially saturated with oil, replace the filter. Test the crankcase ventilating
(CCV) system for proper operation.
(5) Wash the air cleaner cover and body/housing
(Figs. 10) with cleaning solvent and wipe dry.
Fig. 10 Air Cleaner Body/Housing & Cover
(6) Install the air cleaner filter element and attach the cover to the body/housing.
CRANKCASE VENTILATION SYSTEM
All Jeep t 2.5L and 4.0L engines are equipped with a crankcase ventilation (CCV) system. Refer to
Group 25—Emissions, for additional information.
FUEL USAGE STATEMENT—GAS ENGINES
Jeep t vehicles are designed to meet all emission regulations and provide excellent fuel economy using high quality unleaded gasoline. Only use unleaded gasolines having a minimum posted octane of 87.
If a Jeep t vehicle develops occasional light spark knock (ping) at low engine speeds, this is not harmful. However, continued heavy knock at high speeds can cause damage and should be
checked immediately. Engine damage as a result of heavy knock operation may not be covered by the new vehicle warranty.
In addition to using unleaded gasoline with the proper octane rating, those that contain deter- gents, corrosion and stability additives are recommended.
Using gasolines that have these additives will help improve fuel economy, reduce emissions and maintain vehicle performance. Generally, premium unleaded gasolines contain more additive than regular unleaded gasolines.
Poor quality gasoline can cause problems such as hard starting, stalling and stumble. If these problems occur, use another brand of gasoline before considering servicing the vehicle.
GASOLINE/OXYGENATE BLENDS
Some fuel suppliers blend unleaded gasoline with materials that contain oxygen such as alcohol, MTBE and ETBE. The type and amount of oxygenate used in the blend is important. The following are generally used in gasoline blends:
ETHANOL
Ethanol (Ethyl or Grain Alcohol) properly blended, is used as a mixture of 10 percent ethanol and 90 percent gasoline. Gasoline with ethanol may be used in your vehicle.
METHANOL
CAUTION: Do not use gasolines containing methanol. Use of methanol/gasoline blends may result in starting and driveability problems. In addition, damage may be done to critical fuel system components.
Methanol (Methyl or Wood Alcohol) is used in a variety of concentrations blended with unleaded gasoline. You may encounter fuels containing 3 percent or more methanol along with other alcohols called cosolvents.
Problems that are the result of using methanol/gasoline blends are not the responsibility of Chrysler
Corporation. They may not be covered by the vehicle warranty.
MTBE/ETBE
Gasoline and MTBE (Methyl Tertiary Butyl Ether) blends are a mixture of unleaded gasoline and up to
15 percent MTBE. Gasoline and ETBE (Ethyl Tertiary Butyl Ether) are blends of gasoline and up to
17 percent ETBE. Gasoline blended with MTBE or
ETBE may be used.
CLEAN AIR GASOLINE
Many gasolines are now being blended that contribute to cleaner air, especially in those areas of the country where air pollution levels are high. These new blends provide a cleaner burning fuel and some are referred to as Reformulated Gasoline.
0 - 18 LUBRICATION AND MAINTENANCE
J
In areas of the country where carbon monoxide levels are high, gasolines are being treated with oxygenated materials such as MTBE, ETBE and ethanol.
Chrysler Corporation supports these efforts toward cleaner air and recommends the use of these gasolines as they become available.
IGNITION CABLES, DISTRIBUTOR CAP AND
ROTOR
REQUIRED IGNITION SYSTEM MAINTENANCE
The ignition cables, distributor cap and rotor must be replaced after each 96 000-km (60,000-miles). Refer to Group 8D—Ignition Systems for additional information.
IGNITION TIMING
The ignition timing for 2.5L and 4.0L engines is not adjustable. Refer to the specifications listed on the engine Emission Control Information Label. Refer to Group 25—Emission Control Systems for additional information.
SPARK PLUGS
REQUIRED MAINTENANCE
The spark plugs must be replaced after each 48
000-km (30,000-miles). Refer to the Spark Plugs chart below and to Group 8D—Ignition Systems for additional information.
SPARK PLUGS
BATTERY
RECOMMENDED MAINTENANCE
The battery electrolyte level should be checked and the cable clamps should be inspected for corrosion.
This should be done when the oil is changed and the oil filter is replaced.
The battery cables should be inspected for abnormal clamp and battery terminal post corrosion. Service the terminals and cable clamps as necessary.
In addition, the general condition of the battery should be determined before the start of cold and hot weather seasons. If the battery condition is marginal or worse, it should be replaced.
Care should be taken when disposing a battery after removal from a vehicle. Lead-acid batteries are highly poisonous and, when indiscriminately disposed, could create a problem for the environment. Contact the applicable local city or county government agency to determine where automobile (lead-acid) batteries can be properly disposed in the local area.
INSPECTION/SERVICE
WARNING: WEAR SAFETY GLASSES, RUBBER
GLOVES AND PROTECTIVE CLOTHING WHEN HAN-
DLING/SERVICING A BATTERY.
THE BATTERY
ELECTROLYTE CONTAINS SULFURIC ACID AND
WILL CAUSE HARM IF IT CONTACTS SKIN, EYES
OR CLOTHING. IT WILL ALSO DAMAGE PAINTED
(AS WELL AS UN-PAINTED) SURFACES OF A VEHI-
CLE. IF SULFURIC ACID CONTACTS ANY OF
THESE, FLUSH IMMEDIATELY WITH LARGE
AMOUNTS OF WATER. IF SULFURIC ACID CON-
TACTS SKIN OR EYES, GET IMMEDIATE MEDICAL
ATTENTION. DO NOT SMOKE IN THE VICINITY OF
A BATTERY. KEEP OPEN FLAMES AND SPARKS
AWAY FROM BATTERY FILLER CAPS BECAUSE
EXPLOSIVE GAS IS ALWAYS PRESENT.
(1) Disconnect the battery negative cable and then the positive cable.
(2) Clean the battery cable clamps and terminal posts with a wire brush and a battery terminal cleaner.
(3) Pry the battery cell filler caps upward to remove them and inspect each filler well (low-maintenance batteries only, not applicable to maintenancefree batteries). It could possibly be necessary to loosen the battery holddown clamp to remove the caps. Maintain the electrolyte level above the battery plates and at the bottom of the filler well ring. Add distilled water or low-mineral content drinking water, if necessary. In freezing weather (below 0°C/
32°F), add the water just before driving to ensure that it mixes thoroughly with the electrolyte. This will prevent it from freezing.
(4) Remove the battery holddown strap and clean the battery case/battery tray.Clean with bicarbonate of soda (baking soda) and water. Rinse and dry the battery case/tray thoroughly after cleaning.
(5) Position the battery in the tray and install the holddown strap. Do not over-tighten the nuts.
(6) Connect the battery positive cable and then the negative cable to the battery.
J
(7) Apply a small amount of chassis lubricant (or an equivalent protective coating) to the cable terminals to minimize corrosion.
RUBBER AND PLASTIC DUCTS/HOSES/TUBING
RECOMMENDED MAINTENANCE
Rubber and plastic ducts/hoses/tubing should be inspected at the same time the engine oil is changed and the oil filter is replaced.
The conditions associated with vehicle operation determines the usable life of the rubber and plastic ducts/hoses/tubing. These conditions include:
• the extent and quality of vehicle maintenance,
• the geographic area of vehicle operation, and
• the length of exposure time to excess heat and chemical contaminants.
DUCT/HOSE/TUBING INSPECTION—EXCEPT
EMISSION CONTROL HOSES/TUBING
Refer to Group 25—Emission Control Systems.
Engine performance could be affected by air leaks into various hoses.
LUBRICATION AND MAINTENANCE 0 - 19
Fig. 12 Intake Air Duct (XJ)—Typical
Fig. 13 Washer Fluid Tubing—Typical
Fig. 11 Brake Booster Vacuum Hose (XJ)—Typical
Rubber/plastic ducts, hoses and tubing should be replaced immediately if there is any evidence of deterioration.
(1) Inspect all hose fittings for looseness and corrosion. Inspect rubber ducts (Fig. 12) and hoses for brittleness and cracks. Examine the hose ends (those that are slipped over nipple connectors) for splits.
(2) Inspect surface of hoses and tubing (Fig. 13) for heat and mechanical damage. The hose and tubing that is located near an exhaust manifold should be given special attention.
(3) Inspect the rubber hose routing to ensure that the hoses do not contact any heat source, moving component, etc., that could potentially cause heat or mechanical damage (Figs. 14, 15, and 16).
(4) Inspect all the hose connections to ensure that they are secure and that there is no fluid leakage. In
Fig. 14 ATF Cooler Hoses —XJ Vehicles many instances, liquid lubricants are used to aid in the connection of hoses to couplings.
0 - 20 LUBRICATION AND MAINTENANCE
Fig. 15 ATF Cooler Hoses —XJ Vehicles
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ACCESSORY DRIVE BELT
RECOMMENDED MAINTENANCE
The accessory drive belt should be inspected for cracks, fraying, and excessive wear. If necessary, refer to Group 7—Cooling Systems for replacement procedures and adjustment specifications.
REQUIRED MAINTENANCE
The drive belt must be adjusted after each 48
000-km (30,000-miles) interval of vehicle operation has elapsed. The accessory drive belt must be replaced after each 96 000-km (60,000-miles). If necessary, refer to Group 7—Cooling Systems.
EXHAUST SYSTEM
REQUIRED MAINTENANCE
The general condition of the exhaust system must be inspected after each 12 000-km (7,500-miles).
An exhaust system must be properly aligned to prevent stress, leakage, and vehicle body contact.
Fig. 16 ATF Cooler Hoses (4.0L)—YJ Vehicles
ENGINE SUPPORTS
RECOMMENDED MAINTENANCE
The general condition of the engine supports should be inspected at the same time as the engine oil is changed and the oil filter is replaced.
INSPECTION
(1) Test the hardware that attaches the engine cylinder block to the engine support brackets (Figs. 17 and 18) for the specified tightening torque.
(2) Inspect the rubber in the engine support cushions for softening and swelling. Slight surface deterioration and wear at the ends will not affect the functioning of an engine support.
Fig. 17 Front Engine Support—Typical
Fig. 18 Rear Engine Support—Typical
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LUBRICATION AND MAINTENANCE 0 - 21
INSPECTION
When inspecting an exhaust system, inspect for cracked or loose joints, stripped screw/bolt threads, corrosion damage, and worn or broken hangers. Replace all components that are corroded or damaged.
Do not attempt repair. Also, inspect for the following obvious conditions and correct as necessary:
• exhaust system leaks, damage, misalignment;
• contact with body panels metal or the frame; and
• catalytic converter bulging or excessive heat damage.
CAUTION: A catalytic converter will become contaminated if leaded gasoline is burned in the engine. If this occurs, the complete converter must be replaced.
AIR-CONDITIONER COMPRESSOR/HOSES/
FITTINGS
RECOMMENDED MAINTENANCE
The general condition of the A/C compressor, hoses and fittings should be inspected at the same time as the engine oil is changed (Figs. 19, 20 and 21).
LUBRICANT AND REFRIGERANT
In addition to inspection, the lubricant level in the compressor (Fig. 22) should be determined if there are indications that oil was lost.
Loss of lubricating oil usually accompanies a loss of refrigerant. The presence of bubbles/white foam within the receiver/drier sight glass indicates that some loss of refrigerant has occurred.
For additional information involving the A/C system, refer to Group 24—Heater And Air Conditioning.
Fig. 19 A/C System (XJ)—2.5L Engine
Fig. 21 A/C System (YJ)—4.0L Engine
Fig. 20 A/C System (XJ)—4.0L Engine
Fig. 22 A/C Compressor—Typical
0 - 22 LUBRICATION AND MAINTENANCE
DRIVETRAIN
J
INDEX
page
Automatic Transmission
. . . . . . . . . . . . . . . . . . . . 23
Drive Shafts
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Front and Rear Axles
. . . . . . . . . . . . . . . . . . . . . 26
Hydraulic Clutch
. . . . . . . . . . . . . . . . . . . . . . . . . 22
page
Manual Transmission
. . . . . . . . . . . . . . . . . . . . . . 22
Rubber and Plastic Hoses/Tubing
Transfer Case
. . . . . . . . . . . . . . . . . . . . . . . . . . . 25
HYDRAULIC CLUTCH
RECOMMENDED MAINTENANCE
Check fluid level in the hydraulic clutch master cylinder reservoir (Fig. 1) at the same time engine oil is changed and oil filter is replaced. Add fluid as necessary.
relation to the level indicator ring (Fig. 3) located inside the reservoir. If necessary, add fluid until the height is level with the indicator ring.
Fig. 2 Hydraulic Clutch Master Cylinder Fluid
Reservoir
Fig. 1 Hydraulic Clutch (YJ)—Typical
FLUID SPECIFICATION
The only fluid recommended for use in a hydraulic clutch system is MOPAR Brake And Hydraulic
Clutch Fluid., or an equivalent fluid.
CAUTION: Never use reclaimed brake fluid or fluid from an unsealed container. In addition, do not use fluid from a container that has been opened and allowed to stand for an extended length of time.
Moisture in the air can be absorbed by the fluid, which causes dilution with loss of effectiveness.
FLUID LEVEL
Remove the master cylinder fluid reservoir cap
(Fig. 2). The fluid level is determined by its height in
Fig. 3 Hydraulic Clutch Fluid Level
MANUAL TRANSMISSION
RECOMMENDED MAINTENANCE
The lube oil level in manual transmissions should be determined at the same time as the engine oil is changed and the oil filter is replaced. Add lube oil as necessary.
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LUBRICATION AND MAINTENANCE 0 - 23
Under normal driving conditions, manual transmission lube oil should be changed after each 60
000-km (37,500 miles). With severe driving conditions, after each 29 000-km (18,000 miles).
LUBRICANT SPECIFICATION
When it becomes necessary to add to or change the lube oil in a Jeep t manual transmission, use SAE
75W-90, API Quality Grade GL-5 gear lubricant.
LUBRICANT LEVEL
The fill-hole plug for all manual transmissions is located on the right side of the case (Fig. 4). Determine the lubricant level according to the following procedure.
(4) Remove the drain-hole plug and drain the lube oil from the transmission into the container.
Care should be exercised when disposing used lube oil after it has been drained from a transmission.
(5) Install the drain-hole plug in the transmission.
Tighten the plug with 37 N
I m (27 ft. lbs.) torque.
(6) Fill the transmission until the lube oil begins to drip out of the fill hole with SAE 75W-90, API
Quality Grade GL-5 gear lubricant.
(7) Install the fill-hole plug in the transmission.
Tighten the plug with 37 N I m (27 ft. lbs.) torque.
(8) Remove the support and lower the vehicle.
AUTOMATIC TRANSMISSION
RECOMMENDED MAINTENANCE
Check fluid level in automatic transmissions (Fig.
5) the same time the engine oil is changed and the oil filter is replaced. Add ATF as necessary.
Fig. 4 Manual Transmission Fill- & Drain-Hole
Plugs—Typical
(1) Remove the fill-hole plug (Fig. 4) from the transmission. The lube oil should be level with the bottom edge of the fill hole. The level can be slightly below the bottom edge of the fill hole if the lube oil is cold.
If the transmission is warm, lube oil could drip out of the fill hole. This is acceptable but the lube oil should not gush out of the fill hole.
(2) If not acceptable, raise the lube oil level to the bottom edge of the transmission fill hole. Use SAE
75W-90, API Quality Grade GL-5 gear lubricant.
Add lube oil in small amounts to raise the level.
(3) Install the fill-hole plug in the transmission.
Tighten the plug with 37 N I m (27 ft. lbs.) torque.
LUBE OIL CHANGE
When it becomes necessary to change manual transmission lube oil, use the following procedure.
(1) Raise and support the vehicle.
(2) Remove the fill-hole plug from the transmission.
(3) Place a container to collect the lube oil under the transmission drain-hole plug.
Fig. 5 AW-4 Automatic Transmission (XJ)
Under normal driving conditions, the ATF should be changed and the filter replaced after each 48
000-km (30,000-miles). With severe driving conditions, after each 29 000-km (12,000-miles).
ATF SPECIFICATIONS
When it becomes necessary to add fluid (ATF) to a
Jeep t automatic transmission (or when the ATF is replaced), use:
• Mercon™ ATF only for AW-4 automatic transmissions (XJ vehicles), and
•
MOPAR ATF PLUS type 7176 (or an equivalent
Mercon™/Dexron II™ ATF) for 998 automatic transmissions (YJ vehicles).
SPECIAL ADDITIVES
The addition of any special-type fluid to a Jeep t automatic transmission is not recommended. The only exception is the addition of black-light detection
0 - 24 LUBRICATION AND MAINTENANCE
J dye to aid in detecting the source of ATF leaks. The use of transmission sealing additives should also be avoided.
Black-light detection dye is factory-installed in automatic transmissions and, unless the ATF has been drained and re-placed, it is not necessary to add dye.
ATF LEVEL
Determine the ATF level according to the following procedure.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING.
DO NOT PUT YOUR
HANDS NEAR THE DRIVE BELT, PULLEYS OR FAN
BLADE. DO NOT STAND IN A DIRECT LINE WITH
THE FAN BLADE.
(1) Operate the engine and allow the automatic transmission sufficient time to warm to the normal operating temperature (77°C/170°F).
When at normal operating temperature, ATF will be uncomfortable to fingertips when the dipstick is touched. Normally, 25 km (15 miles) is a sufficient driving distance for a transmission to warm to normal operating temperature (77°C/
170°F).
(2) Place the vehicle on a level surface.
(3) Operate the engine at idle speed.
(4) Engage the parking brake.
(5) Place a block in front of and at the rear of one wheel/tire to prevent vehicle movement.
(6) Depress the brake pedal and move the transmission selector lever through all the positions and then place the selector lever in NEUTRAL position.
(7) Remove the dipstick (Fig. 6) from the transmission filler tube and wipe it clean.
(8) Insert the dipstick into the transmission filler tube and seat the cap on top of the tube.
(9) Remove the dipstick and observe the ATF level on both sides of the dipstick. The ATF level is acceptable when it is between the ADD and FULL marks.
(10) While determining the ATF level in a transmission, also note the general condition of the fluid.
Examine the fluid closely. If doubtful about its condition, drain a sample into a small container for evaluation.
(11) If the ATF level is either at or below the ADD mark, add sufficient ATF to raise the level to the
FULL mark on the dipstick.
CAUTION: Do not over-fill an automatic transmission. Over-filling can cause the ATF to foam, which will result in over-heating, fluid oxidation and varnish formation.
(12) When it is necessary to add ATF, insert a long-necked funnel into the transmission filler tube.
Fig. 6 Dipstick & ATF Level—Typical
Fig. 7 Safe ATF Level Above 22°C/72°F
It requires only 0.5 liter (1.0 pint) of ATF to raise the level from the ADD mark to the FULL mark.
(13) Inspect for ATF leaks and correct as necessary.
(14) Remove the wheel/tire blocks.
ATF AND FILTER CHANGE
Automatic transmission fluid (ATF) does not deteriorate or wear out, but it does become contaminated.
These contaminates will eventually restrict passages and orifices. The result is hard or rough shifting, or complete transmission failure. Also, the varnish eventually causes rubber seals to harden and become brittle.
When it is necessary to change the ATF and replace the filter in a Jeep t automatic transmission, use the following procedures.
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LUBRICATION AND MAINTENANCE 0 - 25
DRAINING ATF/FILTER REMOVAL
Drain the automatic transmission fluid (ATF) immediately after stopping the engine (before the ATF cools).
(1) Raise and support the vehicle.
(2) Loosen the transmission pan bolts and drain the original ATF into an appropriate container. Remove the pan bolts, the pan and the gasket.
Care should be exercised when disposing used
ATF after it has been drained from a vehicle transmission.
(3) Remove the screws and the ATF filter (Fig. 8).
Discard the filter.
(8) With the transmission at normal operating temperature, observe the ATF level on the dipstick.
Add ATF (if necessary) to raise the level to the
FULL mark on the dipstick. Only 0.5 liter (1.0 pint) will raise the level from the ADD mark to the
FULL mark when the ATF is at normal operating temperature.
(9) Inspect for fluid leaks and correct as necessary.
(10) Remove the wheel/tire blocks.
TRANSFER CASE
RECOMMENDED MAINTENANCE
The fluid (ATF) level in transfer cases should be determined at the same time as the engine oil is changed and the oil filter is replaced. Add ATF as necessary.
In addition, transfer case ATF should be changed after each 48 000-km (30,000-miles) interval of vehicle operation has elapsed.
FLUID SPECIFICATIONS
If it is necessary to add fluid to a transfer case (or when the fluid is changed), use MOPAR ATF PLUS type 7176 or an equivalent Mercon™/Dexron II™
ATF.
FLUID LEVEL
The transfer case fill-hole plug is located at the rear of the housing (Fig. 9).
Fig. 8 ATF Filter—Typical
FILTER INSTALLATION/ATF RE-FILL
(1) Install a replacement ATF filter. Tighten the screws with 4 N I m (35 in. lbs.) torque.
(2) Clean the pan thoroughly. Install a replacement gasket on the pan. Install the pan with the attaching bolts:
• model AW-4 transmission — tighten the pan bolts with 7 N I m (60 in. lbs.) torque; and
• model 998 transmission — tighten the pan bolts with 17 N I m (150 in. lbs.) torque.
(3) Remove the support and lower the vehicle.
(4) Pour approximately 4.7 liters (5 quarts) of ATF into the filler tube. Use Mercon™ ATF for AW-4 automatic transmissions. Use MOPAR ATF PLUS type
7176 or equivalent, for 998 automatic transmissions.
(5) Place a block in front of and at the rear of one wheel/tire to prevent vehicle movement.
(6) Start the engine and allow it to idle a few minutes.
(7) Apply the brake pedal and engage the parking brake. Move the transmission selector lever through all positions, then place the selector lever in NEU-
TRAL position.
Fig. 9 Transfer Case—Typical
Determine the transfer case fluid (ATF) level according to the following procedure.
(1) Raise and support the vehicle.
(2) Remove the fill-hole plug from the transfer case. The ATF level should be at the bottom edge of the fill hole. The level can be slightly below the bottom edge of the fill hole if the fluid is cold.
0 - 26 LUBRICATION AND MAINTENANCE
J
If the transfer case ATF is warm, it is acceptable for the fluid to drip out of the fill hole. If the fluid gushes out of the fill hole, the level is too high.
(3) If the level is low, raise it to the bottom edge of the fill hole with MOPAR ATF PLUS type 7176 or an equivalent Mercon™/Dexron II™ ATF.
(4) Install the fill-hole plug. Tighten the plug with
47 N I m (35 ft. lbs.) torque.
(5) Remove the support and lower the vehicle.
lubricant in the rear axle. XJ Vehicles equipped with a class III trailer hitch require SAE
75W-140 synthetic gear lubricant in the rear axle.
LUBRICANT LEVEL
Determine the axle differential housing lubricant level according to the following procedure.
(1) Raise and support the vehicle.
(2) Remove the fill-hole plug (Figs. 10 and 11) from the axle differential housing cover. The gear lubricant should be 13 mm (1/2 inch) below the bottom edge of the fill hole.
FLUID CHANGE
When it becomes necessary to change the ATF in a
Jeep t transfer case, use the following procedure.
(1) Raise and support the vehicle.
(2) Remove the fill-hole plug from the transfer case.
(3) Place an appropriate container under the transfer case drain-hole plug.
(4) Remove the drain-hole plug and drain the ATF from the transfer case into the container.
Care should be exercised when disposing used
ATF after it has been drained from a transfer case.
CAUTION: Do not over-tighten the drain and fill-hole plugs. Over-tightening can strip the hole threads and/or crack the aluminum housing.
(5) Install the drain-hole plug in the transfer case.
Tighten the plug with 47 N I m (35 ft. lbs.) torque.
(6) Fill the transfer case to the bottom edge of the fill hole with MOPAR ATF PLUS type 7176 (or an equivalent Mercon™/Dexron II™ ATF).
(7) Install the fill-hole plug in the transfer case.
Tighten the plug with 47 N
I m (35 ft. lbs.) torque.
(8) Remove the support and lower the vehicle.
FRONT AND REAR AXLES
RECOMMENDED MAINTENANCE
The lubricant level in axle differential housings should be determined at the same time as the engine oil is changed and the oil filter is replaced. Add lubricant as necessary.
In addition, with normal driving conditions, the axle lubricant should be changed after each 48
000-km (30,000-miles). With severe driving conditions, after each 29 000-km (12,000-miles).
Fig. 10 Rear Axle—Typical
LUBRICANT SPECIFICATIONS
For normal vehicle operation, use SAE 75W-90,
API Quality Grade GL-5 gear lubricant in all Jeep t front (4WD only) and rear axles. Vehicles equipped with a Trac-Loc rear axle also require a friction modifier additive with the gear lubricant.
When involved in trailer towing applications use SAE 80W-140, API Quality Grade GL-5 gear
Fig. 11 Front Axle (4WD)—Typical
(3) If not acceptable, raise the lubricant level to 13 mm (1/2 inch) below the bottom edge of the fill hole.
Add lubricant in small amounts to raise the level.
(4) Install the fill-hole plug in the differential housing cover. Tighten the plug with 34 N°m (25 ft.
lbs.) torque.
(5) Remove the support and lower the vehicle.
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LUBRICATION AND MAINTENANCE 0 - 27
LUBRICANT CHANGE
When it becomes necessary to change the axle lubricant in a Jeep t front or rear axle, use the following procedure.
(1) Raise and support the vehicle.
(2) Place a container under the axle differential housing.
(3) Remove the axle differential housing cover bolts. Remove the housing cover.
(4) Allow the axle gear lubricant to completely drain into the container.
CAUTION: Do not flush a rear axle Trac-Loc differential. Trac-Loc differentials may be cleaned only by disassembling the unit and wiping the components with clean, lint-free cloth.
(5) Flush the inside of the differential housing with a flushing oil. Do not use water, steam, ker- osene or gasoline for flushing.
(6) Remove any residual RTV sealant/gasket material from the differential housing and cover. Thoroughly clean the contact surfaces with mineral spirits and dry the surfaces completely.
(7) Apply a‘bead of MOPAR RTV Sealant, or an equivalent sealant, around the bolt circle on the housing and on the cover (Fig. 12).
Fig. 13 Differential Housing Cover Installed
(9) Remove the fill-hole plug and add the replacement gear lubricant to the differential housing. Refer to Specifications above.
(10) Install the fill-hole plug. Tighten the plug with 34 N°m (25 ft. lbs.) torque.
(11) Remove the support and lower the vehicle.
DRIVE SHAFTS
RECOMMENDED LUBRICATION
With normal driving conditions, the drive shaft
U-joint couplers and slip yoke splines (Figs. 14 and
15) should be lubricated after each 12 000-km (7,500miles). With severe driving conditions, after each 4
800-km (3,000-miles).
Fig. 12 RTV Sealant Application—Typical
If differential housing cover is not installed within 20 minutes after applying sealant, the sealant must be removed and another bead applied.
(8) Install the cover on the differential housing with the attaching bolts (Fig. 13). Tighten the cover bolts with 47 N I m (35 ft. lbs.) torque.
Fig. 14 Front Drive Shaft (4WD)—Typical
0 - 28 LUBRICATION AND MAINTENANCE
J
• the extent and quality of vehicle maintenance,
• the geographic area of vehicle operation, and
• the length of exposure time to excess heat and chemical contaminants.
(1) Inspect all hose and tubing fittings for looseness and corrosion. Inspect the rubber hoses for brittleness and cracks. Thoroughly inspect the hose ends
(those that are slipped over nipple connectors) for splits (Figs. 16, 17, 18, 19, 20, 21 and 22).
Fig. 15 Rear Drive Shaft (4WD)—Typical
CAUTION: It is very important that drive shafts be lubricated at periodic intervals and that the specified type of lubricant be used. Failure to properly lubricate could result in premature wear of drive shaft components.
LUBRICATION FITTINGS
The drive shaft universal-joint couplers (U-joints) and the front drive shaft slip yoke splines are equipped with Zerk fittings. The (CV-joints) are lubricated when assembled during manufacture and do not require additional lubrication.
LUBRICANT SPECIFICATION
Drive shaft U-joint couplers and slip yoke splines should be lubricated with a lubricant that is identified as NLGI GC-LB lubricant.
SLIP-YOKE SPLINE LUBRICATION
The method below will ensure complete lubrication of the front drive shaft slip-yoke splines (Fig. 14).
(1) Clean the tips of the Zerk type fittings.
(2) Use a gun or another appropriate lubricant dispenser to force pressurized lubricant into the slip yoke Zerk fittings.
(3) When the lubricant appears, cover the pressure relief hole with a finger. Force pressurized lubricant into fitting until it appears at slip-yoke seal.
RUBBER AND PLASTIC HOSES/TUBING
RECOMMENDED MAINTENANCE
The condition of underbody rubber hose and plastic tubing should be inspected for failure at the same time as oil is changed and oil filter is replaced.
HOSE/TUBING INSPECTION
Vehicle operating conditions determine the useable life of underbody hoses and tubing. These conditions include:
Fig. 16 Front Axle Vent Hose (4WD)—XJ Vehicles
Fig. 17 Front Axle Vent Hose—YJ Vehicles
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LUBRICATION AND MAINTENANCE 0 - 29
Fig. 18 Front Axle Vacuum Shift Tubing Fig. 21 Rear Axle Vent Hose—YJ Vehicles
Fig. 19 Transfer Case Vent Hose (4WD)—Typical
Fig. 22 Rear Axle Vent Hose At Wheelhouse—YJ
Vehicles
(2) Inspect the surface of hoses and tubing for heat and mechanical damage. Hose and tubing located close to an exhaust pipe should be given special attention.
(3) Inspect the rubber hose routing to ensure that the hoses do not contact any heat source, moving component, etc., that would potentially cause heat or mechanical damage.
(4) Inspect all the hose connections to ensure that they are secure and there is no fluid leakage. Actual dripping of hot fluid should be noted and the clamps tightened in an attempt to stop the leakage before replacing the hose.
Fig. 20 Rear Axle Vent Hose—XJ Vehicles
0 - 30 LUBRICATION AND MAINTENANCE
CHASSIS AND BODY COMPONENTS
J
INDEX
page
Body Components
. . . . . . . . . . . . . . . . . . . . . . . . 34
Chassis Component and Wheel Bearing
Lubricants
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Front Wheel Bearings
. . . . . . . . . . . . . . . . . . . . . 31
Headlamps
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
page
Manual Steering Gear—YJ Vehicles
Power Brake System
. . . . . . . . . . . . . . . . . . . . . . 32
Power Steering System
. . . . . . . . . . . . . . . . . . . . 31
Steering Linkage and Ball Studs
Tires
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
CHASSIS COMPONENT AND WHEEL BEARING
LUBRICANTS
The chassis component and wheel bearing lubricants that are recommended for Jeep t vehicles are identified by the NLGI Certification Symbol (Fig. 1).
The symbol contains a coded designation that identifies the usage and quality of the lubricant.
Fig. 1 NLGI Lubricant Container Certification/
Identification Symbol
The letter G designates wheel bearing lubricant.
Letter L designates chassis lubricant. When the letters are combined the lubricant can be used for dual applications. The suffix letters C and B designate the level of the lubricant for the application. The letter C represents level available for wheel bearing lubricant
(G) and the letter B represents level available for chassis lubricant (L).
STEERING LINKAGE AND BALL STUDS
RECOMMENDED MAINTENANCE
The general condition of the steering linkage (Fig.
2) should be inspected and the ball studs should be lubricated:
• 2WD vehicles — after each 24 000-km (15,000miles) or six-months interval of vehicle operation has elapsed; or
• 4WD vehicles — after each 12 000-km (7,500miles) or six-months interval of vehicle operation has elapsed.
Fig. 2 Steering Components (XJ)—Typical
LUBRICANT SPECIFICATION
Steering linkage should be lubricated with a dualpurpose, lithium-base lubricant that is identified as
NLGI GC-LB lubricant.
INSPECTION/LUBRICATION
(1) Inspect the steering linkage. Examine the tie rods and the drag link for bending, and the ball studs for looseness and excessive wear.
(2) Replace, as necessary, all torn/ruptured ballstud seals and damaged/defective steering linkage components.
CAUTION: Use care to prevent lubricant from contacting the brake rotors.
(3) Lubricate the ball studs:
• clean the tips of the Zerk type lubrication fittings on the tie-rod and drag-link ball-stud ends to avoid lubricant contamination;
• lubricate the ball studs with high quality, dualpurpose, lithium base chassis/wheel bearing lubricant (NLGI GC-LB lubricant);
• cease the lubricant pressure when lubricant begins to freely exit the base of the seal, or if the seal begins to expand; and
• wipe the excess lubricant from the exterior surfaces of the ball joints and the adjacent surfaces.
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LUBRICATION AND MAINTENANCE 0 - 31
FRONT WHEEL BEARINGS
Only 2WD XJ vehicles are equipped with front wheel bearings. XJ vehicles have semi-floating axle shafts and axle shaft bearings that are lubricated via differential lube oil.
ing and bearing damage. Also, excessive lubricant can be forced out of the wheel hub cavity and contaminate the brake rotor/pads.
RECOMMENDED MAINTENANCE—2WD XJ
VEHICLES
The front wheel bearings should be lubricated (repacked) at the same time as front brake pad/caliper service is conducted.
LUBRICANT SPECIFICATION
Wheel bearings should be lubricated with a lubricant that is identified as NLGI GC-LB lubricant.
INSPECTION/LUBRICATION
(1) Remove the wheel/tire and the disc brake caliper. Do not disconnect the caliper brake fluid hose unless the caliper must also be removed for maintenance. Support the caliper with a hanger to prevent brake fluid hose damage.
(2) Remove the dust cap, the cotter pin, the nut retainer, the adjustment nut, and the thrust washer from the spindle (Fig. 3). Discard the cotter pin.
(8) Partially fill the wheel hub cavity with chassis/ wheel bearing lubricant (NLGI GC-LB lubricant).
(9) Pack the wheel bearings with chassis/wheel bearing lubricant (NLGI GC-LB lubricant). Ensure that sufficient lubricant is forced between the bearing rollers.
(10) Install the wheel inner bearing in the wheel hub and install a replacement seal.
(11) Clean the disc brake rotor contact surfaces, if necessary.
(12) Install the wheel hub/disc brake rotor on the spindle.
(13) Install the wheel outer bearing, the thrust washer, and the spindle nut.
(14) Tighten the spindle nut with 28 N I m (21 ft.
lbs.) torque while rotating the disc brake rotor to seat the bearings.
(15) Loosen the spindle nut 1/2 turn. While rotating the disc brake rotor, tighten the spindle nut with
2 N I m (19 in. lbs.) torque.
(16) Install the nut retainer and a replacement cotter pin.
(17) Clean the dust cap and apply wheel bearing lubricant to the inside surface. Do not fill the dust cap with lubricant.
(18) Install the dust cap.
(19) Install the disc brake caliper.
POWER STEERING SYSTEM
RECOMMENDED MAINTENANCE
The condition of power steering system should be inspected and the fluid level checked. Add fluid as necessary.
Fig. 3 2WD Front Wheel Bearings—XJ Vehicles
(3) Remove the wheel outer bearing from the hub.
(4) Remove the wheel hub/disc brake rotor from the spindle.
(5) Remove the seal and the inner wheel bearing from the hub cavity.
(6) After removal, inspect both front wheel bearing races for indications of pitting, brinelling and excessive heat.
(7) Wipe the spindle clean and apply a small amount of chassis/wheel bearing lubricant (NLGI
GC-LB lubricant) to prevent rust. Wipe the wheel hub cavity clean.
CAUTION: Do not over-fill the wheel hub cavity with lubricant. Excessive lubricant can cause overheat-
FLUID SPECIFICATION
Jeep t power steering systems require MOPAR
Power Steering Fluid, or an equivalent product.
The original power steering fluid installed in
Jeep t vehicles includes black-light leak detection dye.
INSPECTION
Inspect the power steering system (Figs. 4 and 5) for the sources of fluid leaks, steering gear housing cracks and ensure that the steering gear is securely attached to the vehicle frame rail. Inspect the steering damper for leaks and loose connections.
FLUID LEVEL
The fluid level dipstick is attached to the reservoir cap (Fig. 6). The fluid level in the reservoir can be determined with the fluid either hot or cold.
(1) Remove the cap from the reservoir.
0 - 32 LUBRICATION AND MAINTENANCE
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Fig. 4 Power Steering System—XJ Vehicles
Fig. 5 Power Steering System—YJ Vehicles
(2) Depending on fluid temperature, if the level is below the FULL HOT mark or the FULL COLD mark on the dipstick, add power steering fluid.
(3) Install the cap on the reservoir.
MANUAL STEERING GEAR—YJ VEHICLES
RECOMMENDED MAINTENANCE
The manual steering gear should be inspected for damage at the same time as the engine oil is changed and the oil filter is replaced. Repair as nec-
Fig. 6 Power Steering Fluid Reservoir
Dipstick—Typical essary (refer to Group 19—Steering for additional information and service procedures).
POWER BRAKE SYSTEM
RECOMMENDED MAINTENANCE
The condition of the brake system should be inspected and the fluid level in the master cylinder should be checked each time the brake system is serviced. Add brake fluid and repair as necessary.
In addition, the brake system should be operationally tested periodically to ensure that it is functioning normally.
FLUID SPECIFICATION
Jeep t power brake systems require MOPAR
Heavy-Duty Brake Fluid, or an equivalent product identified as conforming to FMVSS No. 116, DOT-3 and SAE J-1703 specifications.
Use new brake fluid only when adding fluid to the reservoir, to fill the brake system. Never use reclaimed fluid.
BRAKE FLUID LEVEL
STANDARD POWER BRAKE SYSTEM
(1) Clean the cover and the sides of the brake fluid reservoir.
(2) Detach the bail retainer from the reservoir cover and remove the cover from the reservoir.
(3) The brake fluid level should be 6 mm (1/4 in) below the rim of each reservoir well for XJ and YJ
Vehicles (Fig. 7). If not, add brake fluid as necessary.
(4) Inspect the reservoir cover bail retainer for tension and the cover for proper fit. The cover should fit tight and have a good seal.
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LUBRICATION AND MAINTENANCE 0 - 33
Fig. 7 Reservoir Fluid Level—Typical
(5) Inspect the reservoir rubber diaphragm seal for cracks, cuts and distortion.
(6) Inspect the brake fluid tubing fittings and the master cylinder housing for indications of fluid leakage. Repair as necessary.
(7) Install the brake fluid reservoir cover.
ANTI-LOCK BRAKE SYSTEM—XJ VEHICLES
The anti-lock brake system fluid reservoir for XJ
Vehicles is located in the engine compartment at the left side of the dash panel.
(1) Turn the ignition switch ON and allow the pump motor to operate until it automatically de-energizes.
(2) Clean the cover before removing it.
CAUTION: Over-filling could cause fluid overflow and possible reservoir damage when the pump motor energizes.
(3) The brake fluid level should be no lower than the MIN arrow indicator on the side of the reservoir
(Fig. 8). If not, add brake fluid as necessary. Raise the fluid level to the MAX arrow indicator only. Do not over-fill the reservoir.
(4) Turn the ignition switch OFF.
BRAKE SYSTEM INSPECTION
BRAKE FLUID HOSES/TUBING
(1) Inspect all brake fluid rubber hoses (Fig. 9) for cracks, swelling, kinks, a distorted condition and fluid leakage.
(2) Inspect the brake fluid hoses and tubing that are routed along the frame rail.
PADS/LININGS, ADJUSTER, WHEEL CYLINDERS AND
CALIPER
The front disk brake pads can be visually inspected via the brake caliper inspection ports.
Fig. 8 Reservoir Fluid Level—Anti-Lock Brake
System
Fig. 9 Rubber Brake Fluid Hose—Typical
(1) Inspect the brake pads and linings for excessive wear, cracks, charred surfaces and broken rivets.
(2) Inspect the brake pads and linings for contamination with brake fluid, axle lubricant and/or another fluid.
(3) Replace the brake pads and/or linings if they are worn to within 0.78 mm (1/32 in) of the rivet head.
(4) Operate the rear brake self-adjuster lever and pivot. Test the operation of the self-adjuster screw for ease of movement.
(5) Inspect the self-adjuster components for bent areas, frayed cables, loose or overheated springs, and a binding condition.
0 - 34 LUBRICATION AND MAINTENANCE
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(6) Inspect the disc brake caliper dust boot for correct installation, damage/tears and indications of brake fluid leakage. Inspect the bushings and pins for corrosion, tears and a binding condition.
(7) Pull the rear wheel cylinder dust boot back to expose the wheel cylinder housing and inspect for fluid leaks. Inspect the pistons and cylinder bores for proper appearance.
(8) Inspect the brake differential warning valve and housing for indications of leakage, kinked hoses and loose fittings.
PARK BRAKE
(1) As applicable, engage the park brake lever or pedal and then release it.
(2) If the park brake is functioning normally, test it for smooth operation and vehicle-holding capability.
(3) Inspect the park brake cables for kinks, fraying and a binding condition.
(4) With the park brake released, the rear wheels should rotate without restriction. Adjust the park brake cable tension at the equalizer (Fig. 10), if necessary.
Fig. 10 Park Brake Equalizer (XJ)—Typical
(5) Repair any park brake malfunctions.
BRAKE OPERATIONAL TEST
(1) Drive the vehicle and test for proper brake action.
(2) Note any indication of drum/rotor overheating, wheel dragging or the vehicle pulling to one side when the brakes are applied.
(3) Evaluate any performance complaints received from the owner/operator.
(4) Repair the brake system as necessary (refer to
Group 5—Brakes for additional information and service procedures).
TIRES
RECOMMENDED MAINTENANCE
The general condition of the tires and the inflation pressures should be inspected at the same time the engine oil is changed and the oil filter is replaced.
In addition, the tires/wheels should be rotated periodically to ensure even tread wear and maximum tread life. The tires/wheels should be rotated initially after the first 12 000-km (7,500-miles). Thereafter, after each 24 000-km (15,000-miles) interval of vehicle operation has elapsed.
INSPECTION
Inspect the tires for excessive wear, damage, etc.
Test the tires for the recommended inflation pressure. Refer to the tire inflation pressure decal located on the inside of the glove box door, and also to Group
22—Tires And Wheels.
ROTATION
Refer to Group 22—Tires And Wheels for the recommended method of tire/wheel rotation for a Jeep t vehicle.
BODY COMPONENTS
RECOMMENDED MAINTENANCE
Body components should be lubricated (as required) after each 48 000-km (30,000-miles) interval of vehicle operation has elapsed.
LUBRICANT SPECIFICATIONS
All applicable exterior and interior body components should be:
• inspected for excessive wear,
• cleaned, and
• all pivot/sliding contact areas of the components should be lubricated with the specified lubricant.
Refer to the Body Lubricant Specifications chart below. When excessive wear is apparent, replace/repair as necessary.
LUBRICATION
All pivoting and sliding contact areas, including:
• seat tracks,
• door hinges/latches/strikers, and
• liftgate/tailgate/hood hinges (Fig. 11), should be lubricated periodically to ensure quiet, easy operation and to protect against wear and corrosion.
(1) As required, lubricate the body components with the specified lubricants.
(2) When lubricating door weatherstrip seals, apply the lubricant to a cloth and wipe it on the seal.
(3) Prior to the application of lubricant, the component should be wiped clean to remove dust, grit and debris. After lubrication, any excess lubricant should be removed.
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LUBRICATION AND MAINTENANCE 0 - 35
BODY LUBRICANT SPECIFICATIONS
Fig. 11 Hood Hinge Lubrication—XJ Vehicles
(4) Extra close attention should be given to external key lock cylinders during the autumn and winter months to ensure protection from water and ice.
(5) Extra close attention should also be given to the hood latch components to ensure proper functioning.
HEADLAMPS
RECOMMENDED MAINTENANCE
Approximately every six months the headlamps should be displayed on a vertical test surface. This will ensure that the headlamps are positioned for safe night-time driving.
BEAM AIM ADJUSTMENT
(1) Changes in the vehicle front and rear suspension will alter the headlamp beam patterns and this can cause unsafe night-time driving conditions.
(2) If a vehicle is loaded the headlamp beam patterns should be displayed on an vertical test surface and the headlamps re-aimed.
(3) Observe the headlamp beam patterns on an appropriate vertical test surface and, if necessary, adjust the headlamp beam aim.
(4) If necessary, refer to Group 8L—Lamps for headlamp aim adjustment procedures.
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FRONT SUSPENSION AND AXLE 2 - 1
FRONT SUSPENSION AND AXLE
CONTENTS page
AXLE NOISE/VIBRATION DIAGNOSIS
. . . . . . . 16
FRONT WHEEL ALIGNMENT
. . . . . . . . . . . . . . . 5
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1
MODEL 30 AXLE AND TUBE AXLE (2WD)
. . 20
page
TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . . 47
XJ FRONT SUSPENSION
. . . . . . . . . . . . . . . . . 10
YJ FRONT SUSPENSION
. . . . . . . . . . . . . . . . . 13
FRONT SUSPENSION
GENERAL INFORMATION
XJ VEHICLES
The Cherokee front suspension is a link/coil design comprised of (Fig. 1);
• Drive axle (4WD), tube axle (2WD)
• Track bar
• Stabilizer bar
•
Upper and lower suspension arms
• Coil springs
• Dual-action shock absorbers
•
Jounce bumpers (used to limit the travel of the suspension)
The link/coil suspension allows each wheel to adapt to different road surfaces without greatly affecting the opposite wheel. Wheels are attached to a hub/ bearings which bolts to the knuckles. The hub/bearing is not serviceable and is replaced as a unit.
Steering knuckles pivot on replaceable ball studs attached to the axle tube yokes.
The upper and lower suspension arms are different lengths, with bushings at both ends. They bolt the
Fig. 1 XJ Front Suspension
2 - 2 FRONT SUSPENSION AND AXLE
J axle assembly to the frame. The lower arms uses shims at the frame mount to allow for adjustment of caster and pinion angle. The suspension arm travel
(jounce or rebound) is limited through the use of rubber bumpers.
Suspension components which use rubber bushings should be tightened at vehicle ride height. This will prevent premature failure of the bushing and maintain ride comfort. Bushings must never be lubricated.
The coil springs control ride quality and maintain proper ride height. The coil springs mount up in the fender shield which is part of the unitized body bracket. A rubber isolator is located between the top of the spring and the frame. The bottom of the spring seats on a axle pad and is retained with a clip.
The shock absorbers dampen jounce and rebound of the vehicle over various road conditions. The top of the shock absorbers are bolted to the frame. The bottom of the shocks are bolted to the axle spring bracket.
The stabilizer bar is used to minimize vehicle front sway during turns. The spring steel bar helps to control the vehicle body in relationship to the suspension. The bar extends across the front underside of the chassis and connects to the frame rails. Links are connected from the bar to the axle brackets. Stabilizer bar mounts are isolated by rubber bushings.
The track bar is used to minimize front axle sideto-side movement. The bar is attached to a frame rail bracket with a ball stud and isolated with a bushing at the axle bracket.
TUBE AXLE (2WD VEHICLES)
The front axle used on two-wheel drive vehicles is a one-piece, tubular axle (Fig. 2). The tubular axle mounts in the same bracketry as does the four-wheel drive front axle. The steering knuckles and hub bearing assemblies are the same as used on the Model 30 drive axle.
YJ VEHICLES
The Wrangler (YJ) front suspension is leaf spring design comprised of (Fig. 3);
• Drive axle
• Track bar
• Stabilizer bar
• Leaf springs
• Dual-action shock absorbers
• Jounce bumpers (used to limit the travel of the suspension)
The front suspension uses semi-elliptic multi-leaf springs mounted on the drive axle. The rearward end of the springs are mounted to the frame rail hangers through rubber bushings. The bushings isolate road noise as the springs move. The forward end of the springs are attached to the frame with shackles. The spring and shackles use rubber bushings to isolate road noise. The shackles allow the springs to change
Fig. 2 Front Axle— 2WD Vehicles
Fig. 3 YJ Front Suspension their length as the vehicle moves over various road conditions. The spring and axle travel (jounce or rebound) is limited through use of rubber bumpers mounted on the frame.
Suspension components which use rubber bushings should be tightened at vehicle ride height. This will prevent premature failure of the bushing and maintain ride comfort. The bushings should never be lubricated.
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FRONT SUSPENSION AND AXLE 2 - 3
The shocks absorbers dampen jounce and rebound of the vehicle over various road conditions. The top of the shock absorbers are bolted to the frame. The bottom of the shocks are bolted to the axle bracket.
The stabilizer bar is used to minimize vehicle front sway during turns. The spring steel bar helps to control the vehicle body in relationship to the suspension. The bar extends across the front underside of the chassis and connects to the frame rails. Links are connected from the bar to the axle brackets. Stabilizer bar mounts are isolated by rubber bushings.
The track bar is used to minimize front axle sideto-side movement. The track bar is attached to a frame rail bracket and the axle bracket.
The bar uses bushings at both ends.
FRONT DRIVE AXLE
It is not necessary to remove the complete axle from the vehicle for routine differential service. If the differential housing or axle shaft tubes are damaged, the complete axle assembly can be removed and serviced.
For complete drive axle assembly removal and installation refer to Drive Axle Assembly Replacement in this Group.
The removable cover provides for servicing without removing axle from vehicle.
The integral type housing, hypoid gear design has the centerline of the pinion set above the centerline of the ring gear.
The Model 30 axle has the assembly part number and gear ratio listed on a tag. The tag is attached to the housing cover (Fig. 4). Build date identification codes are stamped on the axle shaft tube cover side.
Fig. 4 Model 30 Differential Cover
XJ and YJ axles are equipped with an optional
A.B.S. brake system. The A.B.S. tone rings are pressed onto the axle shaft near the hub and knuckle. For additional information on the A.B.S.
system refer to Group 5, Brakes.
•
XJ vehicles use a non-disconnect axle.
• YJ vehicles use a vacuum disconnect axle (Fig. 5).
Fig. 5 Disconnect Feature
STANDARD DIFFERENTIAL OPERATION
The differential gear system divides the torque between the axle shafts. It allows the axle shafts to rotate at different speeds when turning corners.
Each differential side gear is splined to an axle shaft. The pinion gears are mounted on a pinion mate shaft and are free to rotate on the shaft. The pinion gear is fitted in a bore in the differential case and is positioned at a right angle to the axle shafts.
In operation, power flow occurs as follows:
• Pinion gear rotates the ring gear
• Ring gear (bolted to the differential case) rotates the case
• Differential pinion gears (mounted on the pinion mate shaft in the case) rotate the side gears
• Side gears (splined to the axle shafts) rotate the shafts
During straight-ahead driving, the differential pinion gears do not rotate on the pinion mate shaft. This occurs because input torque applied to gears is divided and distributed equally between the two side gears. As a result, the pinion gears revolve with the pinion mate shaft but do not rotate around it (Fig. 6).
When turning corners, the outside wheel must travel a greater distance than the inside wheel. This difference must be compensated for in order to prevent the wheels from scuffing and skidding through the turn. To accomplish this, the differential allows the axle shafts to turn at unequal speeds (Fig. 7). In this instance, the input torque applied to the pinion gears is not divided equally. The pinion gears now rotate around the pinion mate shaft in opposite directions. This allows the side gear and axle shaft attached to the outside wheel to rotate at a faster speed.
2 - 4 FRONT SUSPENSION AND AXLE
Fig. 6 Differential Operation—Straight-Ahead
Driving
Fig. 7 Differential Operation—On Turns
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FRONT SUSPENSION AND AXLE 2 - 5
FRONT WHEEL ALIGNMENT page
Alignment Measurements and Adjustments
General Information
. . . . . . . . . . . . . . . . . . . . . . . . 5
INDEX
page
Pre-Alignment Inspection
. . . . . . . . . . . . . . . . . . . . 6
GENERAL INFORMATION
Front wheel alignment involves the correct positioning of the wheels in relation to the vehicle. The positioning is accomplished through suspension and steering linkage adjustments. An alignment is considered essential for efficient steering, good directional stability and to maximize tire wear. The most important measurements of front end alignment are caster, camber and toe position.
Routine inspection of the front suspension and steering components is a good preventative maintenance practice. Inspection also helps to ensure safe operation of the vehicle.
•
CASTER is the forward or rearward tilt of the steering knuckle from vertical. Tilting the top of the knuckle rearward provides positive caster. Tilting the top of the knuckle forward provides negative caster.
Caster is a directional stability angle which enables the front wheels to return to a straight ahead position after turns (Fig. 1).
• CAMBER is the inward or outward tilt of the wheel relative to the center of the vehicle. Tilting the top of the wheel inward provides negative camber.
Tilting the top of the wheel outward provides positive camber. Incorrect camber will cause wear on the inside or outside edge of the tire (Fig. 1).
• WHEEL TOE POSITION is the difference between the leading inside edges and trailing inside edges of the front tires (Fig. 1). Incorrect wheel toe position is the most common cause of unstable steering and uneven tire wear. The wheel toe position is the final front wheel alignment adjustment.
• STEERING AXIS INCLINATION ANGLE is measured in degrees and is the angle that the steering knuckles are tilted (Fig. 1). The inclination angle has a fixed relationship with the camber angle. It will
Fig. 1 Wheel Alignment Measurements
2 - 6 FRONT SUSPENSION AND AXLE
J not change except when a spindle or ball stud is damaged or bent. The angle is not adjustable and the damaged component(s) must be replaced to correct mis-alignment.
CAUTION:Do not attempt to modify any suspension or steering component by heating and bending.
PRE-ALIGNMENT INSPECTION
Before starting a front wheel alignment, the following inspection and necessary corrections must be completed.
(1) Tires with the same recommended air pressure, size, and thread wear. Refer to Group 22, Tires And
Wheels for diagnosis information.
(2) Front wheel bearings for wear.
(3) Ball studs, steering linkage pivot points and steering gear for looseness, roughness, binding or wear. Refer to Group 19, Steering for additional information.
(4) Front wheels for excessive radial or lateral runout and unbalance. Refer to Group 22, Tires And
Wheels for diagnosis information.
(5) Suspension components for wear and noise.
Check components for correct torque. Refer to Groups
2 and 3, Suspension and Axle for additional information.
ALIGNMENT MEASUREMENTS AND ADJUSTMENTS
Before each alignment reading, the vehicle should be jounced (rear first, then front). Grasp each bumper at the center and jounce the vehicle up and down several times. Always release the bumper in the down position. Set the front end alignment to specifications with the vehicle at its NOR-
MALLY RIDE HEIGHT.
ever, if steering wheel does not return toward the center position unassisted, an incorrect caster angle is probable.
Caster can be adjusted by installing the appropriate size shims (Fig. 2, 3). Changing caster angle will also change the front propeller shaft angle.
The propeller shaft angle has priority over caster. Refer to Group 16, Propeller Shafts for additional information.
Fig. 2 Adjustment—YJ Vehicles
CAMBER
The wheel camber angle (Fig. 1) is preset at ZERO
DEGREES (0°). The angle is not adjustable and cannot be altered.
CASTER
The caster angle (Fig. 1) is set at:
• XJ manual transmission, POSITIVE 6.5 DE-
GREES (+6.5°).
• XJ automatic transmission, POSITIVE 8.0 DE-
GREES (+8.0°).
•
YJ all transmissions, POSITIVE 6.0 DEGREES
(+6.0°).
Before checking the caster of the front axle for correct angle. Be sure the axle is not bent or twisted.
Road test the vehicle, and make left and right turns. If the steering wheel returns to the center position unassisted, the caster angle is correct. How-
Fig. 3 Adjustment—XJ Vehicles
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FRONT SUSPENSION AND AXLE 2 - 7
SUSPENSION AND STEERING SYSTEM DIAGNOSIS
2 - 8 FRONT SUSPENSION AND AXLE
Fig. 4 Steering Linkage—XJ Vehicles
TOE POSITION—XJ VEHICLES
The wheel toe position adjustment should be the final adjustment.
(1) Start the engine and turn wheels both ways before straightening the wheels. Secure the steering wheel with the front wheels in the straight-ahead position.
4).
(2) Loosen the adjustment sleeve clamp bolts (Fig.
(3) Adjust the right wheel toe position with the drag link. Turn the sleeve until the right wheel is at specifications. Position the clamp bolts as shown
(Fig. 5) and tighten to 49 N z m (36 ft. lbs.) torque.
Make sure the toe setting does not change during clamp tightening.
(4) Adjust the left wheel toe position with the tie rod. Turn the sleeve until the left wheel is at specifications. Position the clamp bolts as shown (Fig. 5) and tighten to 27 N z m (20 ft. lbs.) torque. Make sure the toe setting does not change during clamp tightening.
(5) Verify the right toe setting.
Fig. 5 Drag Link and Tie Rod Clamp Location
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J
FRONT SUSPENSION AND AXLE 2 - 9
TOE POSITION—YJ VEHICLES
Fig. 6 Steering Linkage
The wheel toe position should be the final front wheel alignment adjustment. In all instances follow the equipment manufacturer’s recommended procedure.
(1) Secure the steering wheel with the front wheels in the straight-ahead position. For vehicles equipped with power steering, start the engine before straightening the wheels.
ALIGNMENT SPECIFICATIONS—XJ VEHICLES
(2) Loosen the adjustment sleeve clamp bolts on the tie rod (Fig. 6).
YJ Vehicles
The tie rod and adjustment sleeve have both right and left hand threads to provide equal adjustment for each wheel.
(3) After the adjustment is completed, position the tie rod adjustment sleeve clamp bolts as shown.
(4) Tighten the adjustment sleeve clamp bolts to
27 N z m (20 ft. lbs.) torque.
(5) The steering wheel can be centered by the drag link. Complete the adjustment. Position the drag link clamp bolts as shown. Tighten the bolts to 49 N z m
(36 ft. lbs.) torque.
ALIGNMENT SPECIFICATIONS—YJ VEHICLES
2 - 10 FRONT SUSPENSION AND AXLE
XJ FRONT SUSPENSION
J
INDEX
page
Axle Bushing Replacement
. . . . . . . . . . . . . . . . . 11
Coil Spring
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Lower Suspension Arm
. . . . . . . . . . . . . . . . . . . . 11
Service Information
. . . . . . . . . . . . . . . . . . . . . . . 10
Shock Absorber
. . . . . . . . . . . . . . . . . . . . . . . . . . 12
page
Spring and Shock Diagnosis
. . . . . . . . . . . . . . . . 12
Stabilizer Bar
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Track Bar
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Upper Suspension Arm
. . . . . . . . . . . . . . . . . . . . 11
SERVICE INFORMATION
CAUTION: Suspension components that use rubber bushings should be tightened with the vehicle at the normal height. It is important to have the springs supporting the weight of the vehicle when the fasteners are torqued. If the springs are not at their normal ride position, vehicle ride comfort could be affected along with premature bushing wear. Rubber bushings must never be lubricated.
TRACK BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the cotter pin and nut from the ball stud end at the frame rail bracket (Fig. 1).
A puller tool may be necessary to separate the ball stud from the frame rail bracket.
(3) Remove the bolt and flag nut from the axle shaft tube bracket (Fig. 1). Remove the track bar.
INSTALLATION
(1) Install the track bar at axle tube bracket. Loosely install the retaining bolt and flag nut (Fig. 1).
(2) It may be necessary to pry the axle assembly over to install the track bar at the frame rail. Install track bar at the frame rail bracket. Install the retaining nut on the stud (Fig. 1).
(3) Remove the supports and lower the vehicle.
(4) Tighten the retaining bolt at the axle shaft tube bracket to 100 N z m (74 ft. lbs.) torque.
(5) Tighten the ball stud nut to 81 N z m (60 ft. lbs.) torque. Install a new cotter pin.
STABILIZER BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Disconnect the stabilizer bar links from the axle brackets (Fig. 2).
(3) Disconnect the stabilizer bar from the links.
(4) Disconnect the stabilizer bar clamps from the frame rails. Remove the stabilizer bar.
Fig. 1 Track Bar Fig. 2 Stabilizer Bar
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FRONT SUSPENSION AND AXLE 2 - 11
INSTALLATION
(1) Inspect stabilizer bar bushings ( Fig. 2). Replace bushings if cracked, cut, distorted, or worn.
(2) Position the stabilizer bar on the frame rail and install the bushings and clamps. Ensure the bar is centered with equal spacing on both sides. Tighten the bolts to 75 N z m (40 ft. lbs.).
(3) Install the links and grommets onto the stabilizer bar and axle brackets (Fig. 2). Tighten the nut at the connecting links at the axle bracket to 95 N z m
(70 ft. lbs.) torque.
(4) Tighten the stabilizer bar to connecting link nut to 36 N z m (27 ft. lbs.) torque.
(5) Remove the supports and lower the vehicle.
UPPER SUSPENSION ARM
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the upper suspension arm nut and bolt at the axle bracket (Fig. 3).
(3) Remove the nut and bolt (Fig. 3) at the frame rail and remove the upper suspension arm.
AXLE BUSHING REPLACEMENT
(1) Remove the upper suspension arm from axle.
Refer to Upper Suspension Arm Removal in this
Group.
(2) Insert Spacer 7932-3 (J-35581-3) around the bushing in the axle bracket ears (Fig. 4).
(3) Assemble and install Bushing Removal/Installer (Fig. 4).
(4) Remove the bushing by tightening the hexhead on Long Nut.
Fig. 3 Upper and Lower Suspension Arms
INSTALLATION
(1) Position the upper suspension arm at the axle and frame rail (Fig. 3).
(2) Install the bolts and finger tighten the nuts
(Fig. 3).
(3) Remove the supports and lower the vehicle.
(4) Tighten the nut at the axle to 75 N z m (55 ft.
lbs.) torque.
Tighten the nut at the frame bracket to 90 N z m (66 ft. lbs.) torque.
Fig. 4 Axle Bracket Bushing Removal
For two-wheel drive axles and right side on
Model 30 axle, do not remove Spacer 7932-3 (J-
35581-3) at this time.
(5) Position the new bushing on Installer.
(6) Install the bushing by tightening the hex-head on Long Nut (Fig. 5). Remove Spacer 7932-3 (J-
35581-3).
(7) Install the upper suspension arm to axle. Refer to Upper Suspension Arm Installation in this Group.
LOWER SUSPENSION ARM
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the lower suspension arm nut and bolt from the axle bracket (Fig. 3).
(3) Remove the nut and bolt (Fig. 3) from the rear bracket and remove the lower suspension arm.
INSTALLATION
(1) Position the lower suspension arm at the axle bracket and rear bracket (Fig. 3).
2 - 12 FRONT SUSPENSION AND AXLE
J
Fig. 5 Axle Bracket Bushing Installation
(2) Install the bolts and finger tighten the nuts
(Fig. 3).
(3) Remove support and lower the vehicle.
(4) Tighten the front and rear nuts to 115 N z m (85 ft. lbs.) torque.
SPRING AND SHOCK DIAGNOSIS
A squeak noise from the shock absorber can be produced if movement between the rubber bushings and the metal occurs. This noise can usually be stopped by tightening the attaching nuts. If the squeak noise persists, inspect for damaged and worn bushings, and attaching components. Repair as necessary.
The shock absorber bushings do not require any type of lubrication. Do not lubricate the bushings to reduce bushing noise. Grease or mineral oil-base lubricants will deteriorate the bushing rubber.
The shock absorbers are not refillable or adjustable. If a malfunction occurs, the shock absorber must be replaced. To test a shock absorber, hold it in an upright position and force the piston into and out of the cylinder four or five times. The action throughout each stroke should be smooth and even.
SHOCK ABSORBER
REMOVAL
(1) Remove the nut, retainer and grommet from the upper stud in the engine compartment (Fig. 6).
(2) Remove the lower nuts and bolts from the axle bracket (Fig. 6). Remove the shock absorber.
INSTALLATION
(1) Position the lower retainer and grommet on the upper stud. Insert the shock absorber through the shock tower hole.
(2) Install the lower bolts and nuts. Tighten nuts to 19 N z m (14 ft. lbs.) torque.
(3) Install the upper grommet and retainer on the stud in the engine compartment. Install the nut and tighten to 10 N z m (8 ft. lbs.) torque.
Fig. 6 Coil Spring & Shock Absorber
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FRONT SUSPENSION AND AXLE 2 - 13
COIL SPRING
REMOVAL
(1) Raise and support the vehicle. Position a hydraulic jack under the axle to support it.
(2) Remove the wheel if necessary.
(3) Mark and disconnect the front propeller shaft from the axle.
(4) Disconnect the lower suspension arms from the axle (Fig. 6).
(5) Disconnect the stabilizer bar link and shock absorber from the axle.
(6) Disconnect the track bar from the frame rail bracket.
(7) Disconnect the drag link from the pitman arm.
(8) Lower the axle until the spring is free from the upper mount. Remove the coil spring clip (Fig. 6) and remove the spring.
(9) Remove the jounce bumper if necessary from the upper spring mount (Fig. 6).
INSTALLATION
(1) Install the jounce bumper on the upper spring mount. Tighten the bolt to 42 N z m (31 ft. lbs.) torque
(Fig. 6).
(2) Position the coil spring on the axle pad. Install the spring clip and bolt (Fig. 6). Tighten bolt to 21
N z m (16 ft. lbs.) torque.
(3) Raise the axle into position until the spring seats in the upper mount.
(4) Connect the stabilizer bar links and shock absorbers to the axle bracket. Connect the track bar to the frame rail bracket.
(5) Install the lower suspension arms to the axle.
DO NOT TIGHTEN AT THIS TIME.
(6) Install the front propeller shaft to the axle.
(7) Remove the supports and lower the vehicle.
(8) Tighten lower suspension arms nuts to 115
N z m (85 ft. lbs.) torque.
YJ FRONT SUSPENSION
INDEX
page
Leaf Spring
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Leaf Spring Eye Bushing Replacement
Service Information
. . . . . . . . . . . . . . . . . . . . . . . 13
Shock Absorber
. . . . . . . . . . . . . . . . . . . . . . . . . . 14
page
Spring and Shock Diagnosis
. . . . . . . . . . . . . . . . 14
Stabilizer Bar
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Track Bar
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
SERVICE INFORMATION
It is important to have the springs supporting the weight of the vehicle when the track bar fasteners are being torqued. If the springs are not at their normal ride position, vehicle ride comfort could be affected along with premature rubber bushing wear.
TRACK BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the retaining nuts and bolts (Fig. 1) from the axle bracket and frame bracket. Remove track bar.
INSTALLATION
(1) Position track bar at axle shaft tube bracket.
Loosely install the retaining bolt and nut (Fig. 1).
(2) Loosely install the retaining bolt and nut at the frame bracket.
(3) Remove support and lower vehicle.
(4) Tighten the retaining nut at the axle shaft tube bracket to 100 N z m (74 ft. lbs.) torque.
(5) Tighten the retaining nut at the frame bracket to 142 N z m (105 ft. lbs.) torque.
Fig. 1 Track Bar
2 - 14 FRONT SUSPENSION AND AXLE
STABILIZER BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the retaining nut from the connecting link bolt (Fig. 2).
J
The shock absorbers are not refillable or adjustable. If a malfunction occurs, the shock absorber must be replaced. To test a shock absorber, hold it in an upright position and force the piston into and out of the cylinder four or five times. The action throughout each stroke should be smooth and even.
SHOCK ABSORBER
REMOVAL
(1) Remove the nut, retainer and grommet from the upper stud on the frame bracket (Fig. 3).
(2) Raise and support the vehicle.
(3) Remove the nut, washers and bolt from the shock absorber lower eye (Fig.3).
Fig. 2 Stabilizer Bar
(3) Remove the retaining clamps from frame rails
(4) Remove the stabilizer bar.
INSTALLATION
(1) Inspect the stabilizer bar bushings (Fig. 2). Replace the bushings if cracked, cut, distorted, or worn.
(2) Position the stabilizer bar on the frame. Install the retaining brackets and fasteners. Tighten bolts to
41 N z m (30 ft. lbs.) torque.
(3) Install the link upper bolts and nuts. Tighten the nuts to 61 N z m (45 ft. lbs.) torque.
(4) Tighten the link spring bracket nuts to 61 N z m
(45 ft. lbs.) torque.
(5) Lower the vehicle.
SPRING AND SHOCK DIAGNOSIS
A squeak noise from the shock absorber or springs can be produced if movement between the rubber bushings and the metal occurs. This noise can usually be stopped by tightening the attaching nuts. If the squeak noise persists, inspect for damaged and worn bushings, and attaching components. Repair as necessary if any of these conditions exist.
The shock absorber bushings do not require any type of lubrication. Do not lubricate the bushings to reduce bushing noise. Grease or mineral oil-base lubricants will deteriorate the bushing rubber.
Fig. 3 Spring & Shock Absorber
(4) Remove the shock absorber.
(5) Remove the remaining grommet and retainer from the shock absorber stud.
INSTALLATION
(1) Position the lower retainer and grommet on the upper stud. Insert the shock absorber through the shock tower hole.
(2) Install the lower bolts and nuts. Tighten the nuts to 61 N z m (45 ft. lbs.) torque.
(3) Install the upper grommet and retainer on the stud on the frame bracket. Install the nut and tighten to 12 N z m (9 ft. lbs.) torque.
LEAF SPRING
REMOVAL
(1) Raise the vehicle.
J
FRONT SUSPENSION AND AXLE 2 - 15
(2) Support the vehicle with jack stands placed under the frame.
(3) Position a hydraulic jack under the axle. Raise the axle to relieve the axle weight from the springs.
(4) Remove the stabilizer bar links attaching nut.
(5) Remove the nuts, the U-bolts and spring bracket from the axle.
(6) Remove the nut and bolt that attaches the spring front eye to the shackle (Fig. 3).
(7) Remove the nut and bolt from the spring rear eye.
(8) Remove the spring from the vehicle.
The spring can be disassembled by removing the spring clips and the center bolt. If the spring bushings require replacement, refer to the bushing removal and installation procedures.
LEAF SPRING EYE BUSHING REPLACEMENT
(1) Assemble tools shown (Fig. 4). Tighten the nut located at the socket wrench end of the threaded rod until the bushing is forced out.
INSTALLATION
(1) Position the spring front eye in the shackle.
Loosely install the attaching bolt and nut. Do not tighten at this time.
(2) Position the rear eye in the hanger bracket.
Loosely install the attaching bolt and nut (Fig. 3). Do not tighten at this time.
(3) Position the axle. Install the spring bracket,
U-bolts and nuts (Fig. 3). Tighten the U-bolt nuts to
122 N z m (90 ft. lbs.) torque.
(4) Attach the stabilizer bar links.
(5) Remove the hydraulic jack.
(6) Remove the support stands and lower the vehicle.
(7) Tighten the front shackle plate nut (Fig. 3) to
135 N z m (100 ft. lbs.) torque.
(8) Tighten the rear eye bracket nut to 142 N z m
(105 ft. lbs.) torque.
Fig. 4 Spring Eye Bushing Removal
(2) Assemble and align the bushing installation tools.
(3) Align the bushing with the spring eye and tighten the nut located at the socket wrench end of the threaded rod. Tighten until the bushing is forced into the spring eye.
The bushing must be centered in the spring eye. The ends of the bushing must be flush or slightly recessed within the end surfaces of the spring eye.
2 - 16 FRONT SUSPENSION AND AXLE
AXLE NOISE/VIBRATION DIAGNOSIS
J page
Driveline Snap
. . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Gear and Bearing Noise
. . . . . . . . . . . . . . . . . . . 16
General Information
. . . . . . . . . . . . . . . . . . . . . . . 16
INDEX
page
Low Speed Knock
. . . . . . . . . . . . . . . . . . . . . . . . 17
Vibration
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
GENERAL INFORMATION
Axle bearing problem conditions are usually caused by:
•
Insufficient or incorrect lubricant
• Foreign matter/water contamination
• Incorrect bearing preload torque adjustment
•
Incorrect backlash (to tight)
When serviced, the bearings must be cleaned thoroughly. They should be dried with lint-free shop towels. Never dry bearings with compressed air.
This will overheat them and brinell the bearing surfaces. This will result in noisy operation after repair.
Axle gear problem conditions are usually the result of:
• Insufficient lubrication
• Incorrect or contaminated lubricant
• Overloading (excessive engine torque) or exceeding vehicle weight capacity
• Incorrect clearance or backlash adjustment
Insufficient lubrication is usually the result of a housing cover leak. It can also be from worn axle shaft or pinion gear seals. Check for cracks or porous areas in the housing or tubes.
Using the wrong lubricant will cause overheating and gear failure. Gear tooth cracking and bearing spalling are indicators of this.
Axle component breakage is most often the result of:
• Severe overloading
•
Insufficient lubricant
• Incorrect lubricant
• Improperly tightened components
Overloading occurs when towing heavier than recommended loads. Component breakage can occur when the wheels are spun excessively. Incorrect lubricant quantity contributes to breakage. Loose differential components can also cause breakage.
Incorrect bearing preload or gear backlash will not result in component breakage. Mis-adjustment will produce enough noise to cause service repair before a failure occurs. If a mis-adjustment condition is not corrected, component failure can result.
Excessive bearing preload may not be noisy. This condition will cause high temperature which can result in bearing failure.
GEAR AND BEARING NOISE
GEAR NOISE
Axle gear noise can be caused by insufficient lubricant. Incorrect backlash, tooth contact, or worn/damaged gears can cause noise.
Gear noise usually happens at a specific speed range. The range is 30 to 40 mph, or above 50 mph.
The noise can also occur during a specific type of driving condition. These conditions are acceleration, deceleration, coast, or constant load.
When road testing, accelerate the vehicle to the speed range where the noise is the greatest. Shift out-of-gear and coast through the peak-noise range.
If the noise stops or changes greatly, check for insufficient lubricant. Incorrect ring gear backlash, or gear damage can cause noise changes.
Differential side and pinion gears can be checked by turning the vehicle. They usually do not cause noise in straight-ahead driving. These gears are loaded during vehicle turns. If noise does occur during vehicle turns, the side or pinion gears could be worn or damaged. A worn pinion gear mate shaft can also cause a snapping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion gear bearings can all produce noise when worn or damaged.
Bearing noise can be either a whining, or a growling sound.
Pinion gear bearings have a constant-pitch noise.
This noise changes only with vehicle speed. Pinion bearing noise will be higher because it rotates at a faster rate. Drive the vehicle and load the differential. If bearing noise occurs the pinion rear bearing is the source of the noise. If the bearing noise is heard during a coast, front bearing is the source.
Worn, damaged differential bearings usually produce a low pitch noise. Differential bearing noise is similar to pinion bearing. The pitch of differential bearing noise is also constant and varies only with vehicle speed.
Axle shaft bearings produce noise and vibration when worn or damaged. The noise generally changes when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
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FRONT SUSPENSION AND AXLE 2 - 17
level. Where axle bearing damage is slight, the noise is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side-gear thrust washers. A worn pinion gear shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually caused by a:
• Damaged drive shaft
• Missing drive shaft balance weight
• Worn, out-of-balance wheels
• Loose wheel lug nuts
•
Worn U-joint
•
Loose spring U-bolts
•
Loose/broken springs
•
Damaged axle shaft bearings
•
Loose pinion gear nut
• Excessive pinion yoke run out
• Bent axle shaft
Check for loose or damaged front-end components or engine/transmission mounts. These components can contribute to what appears to be a rear-end vibration. Do not overlook engine accessories, brackets and drive belts.
All driveline components should be examined before starting any repair.
Refer to Group 22—Tires And Wheels for additional information involving vibration diagnosis.
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted into gear (or the clutch engaged), can be caused by:
• High engine idle speed
• Loose engine/transmission/transfer case mounts
• Worn U-joints
• Loose spring mounts
• Loose pinion gear nut and yoke
• Excessive ring gear backlash
•
Excessive differential side gear-to-case clearance
The source of a snap or a clunk noise can be determined with the assistance of a helper. Raise the vehicle on a hoist with the wheels free to rotate.
Instruct the helper to shift the transmission into gear. Listen for the noise, a mechanics stethoscope is helpful in isolating the source of a noise.
2 - 18 FRONT SUSPENSION AND AXLE
SERVICE DIAGNOSIS
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FRONT SUSPENSION AND AXLE 2 - 19
SERVICE DIAGNOSIS (CONT’D)
2 - 20 FRONT SUSPENSION AND AXLE
MODEL 30 AXLE AND TUBE AXLE (2WD)
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INDEX
page
Axle Bushing Replacement
. . . . . . . . . . . . . . . . . 32
Axle Shaft — Cardan U-Joint . . . . . . . . . . . . . . . . 25
Axle Specifications
. . . . . . . . . . . . . . . . . . . . . . . 46
Backlash and Contact Pattern Analysis
Cleaning/Inspection
. . . . . . . . . . . . . . . . . . . . . . . 35
Differential and Pinion Measurement
Differential Assembly
. . . . . . . . . . . . . . . . . . . . . . 36
Differential Disassembly
. . . . . . . . . . . . . . . . . . . . 34
Differential Installation
. . . . . . . . . . . . . . . . . . . . . 43
Differential Removal
. . . . . . . . . . . . . . . . . . . . . . 32
Differential Shim Pack Measurement and Adjustment . 42
Drive Axle Assembly Replacement—XJ Vehicles
Drive Axle Assembly Replacement—YJ Vehicles
page
Final Assembly
. . . . . . . . . . . . . . . . . . . . . . . . . . 44
Hub Bearing and Axle Shaft
. . . . . . . . . . . . . . . . 24
Information
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Inner Axle Shaft Oil Seal Replacement
Lubricant Change
. . . . . . . . . . . . . . . . . . . . . . . . 22
Lubricant Specifications
. . . . . . . . . . . . . . . . . . . . 20
Pinion Gear Assembly/Installation
Pinion Gear Depth Information
. . . . . . . . . . . . . . 37
Pinion Removal/Disassembly
. . . . . . . . . . . . . . . . 34
Pinion Seal Replacement
. . . . . . . . . . . . . . . . . . 23
Steering Knuckle and Ball Studs
Vacuum Disconnect Axle — YJ Vehicles
INFORMATION
The housing for Model 30 front axles consists of an iron center casting (differential housing) with axle shaft tubes extending from either side. The tubes are pressed into and welded to the differential housing to form a one-piece axle housing.
The integral type housing, hypoid gear design has the centerline of the pinion set above the centerline of the ring gear.
The axle has a fitting for a vent hose used to relieve internal pressure caused by lubricant vaporization and internal expansion.
The axles are equipped with semi-floating axle shafts, meaning that loads are supported by the hub bearings. The axle shafts are retained by nuts at the hub bearings. The hub bearings are bolted to the steering knuckle at the outboard end of the axle tube yoke. The hub bearings are serviced as an assembly.
The axles are equipped with ABS brake sensors.
The sensors are attached to the knuckle assemblies and tone rings are pressed on the axle shaft. Use care when removing axle shafts as NOT to damage the tone wheel or the sensor.
The stamped steel cover provides a means for inspection and servicing the differential.
The Model 30 axle has the assembly part number and gear ratio listed on a tag. The tag is attached to the housing cover. Build date identification codes are stamped on the axle shaft tube cover side.
The differential case is a one-piece design. The differential pinion mate shaft is retained with a roll pin. Differential bearing preload and ring gear backlash is adjusted by the use of shims (select thickness). The shims are located between the differential bearing cones and case. Pinion bearing preload is set and maintained by the use of collapsible spacer.
PINION GEAR DEPTH MEASUREMENT WITH
PINION GAUGE SET 6774, Pinion Block 6733 and
Dial Indicator C-3339 is performed when;
• Axle/differential housing is being replaced
• Original pinion depth shim pack is lost or misplaced
• Replacing the differential case
• Original differential bearing shim pack is lost or misplaced
COMMAND-TRAC—YJ VEHICLES
The Command-Trac system is a vacuum disconnect axle. The system has a two-piece axle shaft coupled together by a shift collar. For two-wheel drive operation, the vacuum motor and shift fork disengages the axle shaft splines. For four-wheel drive operation, the vacuum motor and shift fork engages the splines.
SELEC-TRAC—XJ VEHICLES
The Selec-Trac system is a non-disconnect axle.
Shifting from two-wheel to four-wheel drive is at the transfer case.
For XJ vehicles equipped with Selec-Trac and
ABS brake system, refer to Group 5—Brakes for additional service information.
LUBRICANT SPECIFICATIONS
Multi-purpose, hypoid gear lubricant should be used for Model 30 axles. The lubricant should have
MIL-L-2105C and API GL 5 quality specifications.
MOPAR t
Hypoid Gear Lubricant conforms to both of these specifications.
• The factory fill for the Model 30 axle is SAE 75W gear lubricant. Do not use heavier weight lubri- cant, this will cause axle engagement difficulties.
• The factory installed lubricant quantity for the
NON-DISCONNECT TYPE AXLE is 50 6 1 fluid oz..
•
The factory installed lubricant quantity for the
VACUUM-DISCONNECT TYPE AXLE is 56 6 1 fluid oz..
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FRONT SUSPENSION AND AXLE 2 - 21
Refer to Group 0, Lubrication and Maintenance for additional information regarding temperature range, viscosity and fluid level.
CAUTION: If the axle is submerged in water, the lubricant must be replaced immediately to avoid the possibility of premature axle failure.
DRIVE AXLE ASSEMBLY REPLACEMENT—XJ
VEHICLES
REMOVAL
(1) Raise the vehicle and position support stands under the frame rails slightly in behind the lower suspension arm frame brackets.
(2) Remove the front wheels.
(3) Remove the brake components and ABS brake sensor (if equipped). Refer to Group 5—Brakes.
(4) On 4WD vehicles, disconnect the axle vent hose.
(5) On 4WD vehicles, mark the drive shaft yoke and axle pinion yoke for alignment reference. Disconnect the drive shaft from the axle.
(6) Disconnect the stabilizer bar link at the axle bracket.
(7) Disconnect the shock absorbers from axle bracket.
(8) Disconnect the track bar from the axle bracket.
(9) Disconnect the tie rod and drag link from the steering knuckle. Disconnect the steering dampener from the axle bracket.
(10) Support the axle with a hydraulic jack under the differential.
(11) Disconnect the upper and lower suspension arms from the axle bracket.
(12) Lower the jack enough to remove the axle.
The coil springs will drop with the axle.
(13) Remove the coil springs from the axle bracket.
INSTALLATION
CAUTION: All suspension components that use rubber bushings should be tightened with the vehicle at the ride height. It is important to have the springs supporting the weight of the vehicle when the fasteners are torqued. If the springs are not at their normal ride position, vehicle ride comfort could be affected along with premature rubber bushing wear. Rubber bushings must never be lubricated.
(1) Install the springs and retainer clip. Tighten the retainer bolts to 21 N z m (16 ft. lbs.) torque.
(2) Support the axle on a hydraulic jack under the differential. Position the axle under the vehicle.
(3) Raise the axle with a floor jack and align it with the spring pads.
(4) Position the upper and lower suspension arm at the axle bracket. Install bolts and nuts finger tighten.
(5) Connect the track bar to the axle bracket and install the bolt. Do not tighten at this time.
It is important that the springs support the weight of the vehicle when the track bar is connected. If the springs are not at their usual position, the vehicle ride comfort could be affected.
(6) Install the shock absorber and tighten the bolt to 19 N z m (14 ft. lbs.) torque.
(7) Install the stabilizer bar link to the axle bracket. Tighten the nut to 95 N z m (70 ft. lbs.) torque.
(8) Install the drag link and tie rod to the steering knuckles and tighten the nuts to 47 N z m (35 ft. lbs.) torque. Install the steering dampener to the axle bracket and tighten the nut to 75 N z m (55 ft. lbs.) torque.
(9) Install the brake components and ABS brake sensor (if equipped). Refer to Group 5—Brakes.
(10) On 4WD vehicles, connect the vent hose to the tube fitting.
(11) On 4WD vehicles, align the reference marks and connect the drive shaft to the axle yoke. Tighten the U-joint clamp bolts to 19 N z m (14 ft. lbs.) torque.
(12) Check differential lubricant and add if necessary.
(13) Install the wheel and tire assemblies.
(14) Remove the supports and lower the vehicle.
(15) Tighten the upper suspension arm nuts to 75
N z m (55 ft. lbs.) torque. Tighten the lower suspension arm nuts to 115 N z m (85 ft. lbs.) torque.
(16) Tighten the track bar bolt at the axle bracket to 100 N z m (74 ft. lbs.) torque.
(17) Check the front wheel alignment.
DRIVE AXLE ASSEMBLY REPLACEMENT—YJ
VEHICLES
REMOVAL
(1) Raise the vehicle and position support stands under the frame rails slightly behind the spring frame brackets.
(2) Remove the front wheels.
(3) Remove the brake components and ABS brake sensor (if equipped). Refer to Group 5—Brakes.
(4) Disconnect the axle vent hose and axle shift motor vacuum harness.
(5) Mark the drive shaft yoke and axle pinion yoke for alignment reference. Disconnect the drive shaft from the axle.
(6) Disconnect the stabilizer bar link at the axle bracket.
(7) Disconnect the shock absorbers from axle bracket.
(8) Disconnect the track bar from the axle bracket.
2 - 22 FRONT SUSPENSION AND AXLE
J
(9) Disconnect the tie rod from the steering knuckle. Disconnect the steering dampener from the axle bracket.
(10) Support the axle with a hydraulic jack under the differential. Raise the axle just enough to relieve the axle weight from the springs.
(11) Remove the spring U-bolts from the plate brackets.
(12) Loosen BUT DO NOT REMOVE the bolts that attach the spring rear pivot at the frame rail brackets. This will allow the springs to pivot without binding on the bushings.
(13) Disconnect shackle from the springs and lower the springs to the surface.
(14) Lower the jack enough to remove the axle.
(11) Align the reference marks and connect the drive shaft to the axle yoke. Tighten the U-joint clamp bolts to 19 N z m (14 ft. lbs.) torque.
(12) Check differential lubricant and add if necessary.
(13) Install the wheel and tire assemblies.
(14) Remove the supports and lower the vehicle.
(15) Tighten the spring rear pivot bolt/nut to 142
N z m (105 ft. lbs.) torque. Tighten the spring shackle bolt/nut to 135 N z m (100 ft. lbs.) torque.
(16) Tighten the track bar nut at the axle bracket to 100 N z m (74 ft. lbs.) torque.
(17) Check the front wheel alignment.
INSTALLATION
CAUTION: All suspension components that use rubber bushings should be tightened with the vehicle at the normal height. It is important to have the springs supporting the weight of the vehicle when the fasteners are torqued. If the springs are not at their normal ride position, vehicle ride comfort could be affected along with premature rubber bushing wear. Rubber bushings must never be lubricated.
LUBRICANT CHANGE
The gear lubricant will drain quicker if the vehicle has been recently driven.
(1) Raise and support the vehicle.
(2) Remove the lubricant fill hole plug from the differential housing cover.
(3) Remove the differential housing cover and drain the lubricant from the housing.
(4) Clean the housing cavity with a flushing oil, light engine oil or lint free cloth. Do not use water, steam, kerosene or gasoline for cleaning.
(5) Remove the sealant from the housing and cover surfaces. Use solvent to clean the mating surfaces.
(6) Apply a bead of MOPAR t Silicone Rubber Sealant to the housing cover (Fig. 1). Allow the sealant to cure for a few minutes.
(1) Support the axle on a hydraulic jack under the differential. Position the axle under the vehicle.
(2) Raise the springs and install the spring shackle bolts. Do not tighten at this time.
(3) Lower the axle and align the spring center bolts with the locating holes in the axle pads and plate brackets.
(4) Install the spring U-bolts through the plate brackets and tighten to 122 N z m (90 ft. lbs.) torque.
(5) Connect the track bar to the axle bracket and install the bolt. Do not tighten at this time.
It is important that the springs support the weight of the vehicle when the track bar is connected. If the springs are not at their usual position, the vehicle ride comfort could be affected.
(6) Install the shock absorber and tighten the nut to 61 N z m (45 ft. lbs.) torque.
(7) Install the stabilizer bar link to the axle bracket. Tighten the nut to 61 N z m (45 ft. lbs.) torque.
(8) Install the tie rod to the steering knuckles and tighten the nuts to 47 N z m (35 ft. lbs.) torque. Install the steering dampener to the axle bracket and tighten the bolt to 75 N z m (55 ft. lbs.) torque.
(9) Install the brake components and ABS brake sensor (if equipped). Refer to Group 5—Brakes.
(10) Connect the vent hose to the tube fitting and axle shift motor vacuum harness.
Fig. 1 Typical Housing Cover With Sealant
Install the housing cover within 5 minutes after applying the sealant. If not installed the sealant must be removed and another bead applied.
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FRONT SUSPENSION AND AXLE 2 - 23
(7) Install the cover and any identification tag.
Tighten the cover bolts in a criss-cross pattern to 41
N z m (30 ft. lbs.) torque.
(8) Refill the differential with MOPAR t Hypoid
Gear Lubricant within 13 mm (1/2 in.) below the fill plug hole.
(9) Install the fill hole plug and lower the vehicle.
PINION SEAL REPLACEMENT
CAUTION: The following procedures must be used so the correct pinion bearing preload torque is retained. If this procedure is not followed, the result can be premature failure of the rear axle.
(9) Use Remover W-251 to remove the pinion gear seal (Fig. 3).
REMOVAL
(1) Raise and support the vehicle.
(2) Remove wheel and tire assemblies.
(3) Mark the propeller shaft yoke and pinion yoke for installation alignment reference.
(4) Remove the propeller shaft from the yoke.
(5) Rotate the pinion gear three or four times.
Make sure brakes are not dragging during this procedure.
(6) Measure the amount of torque (in Newtonmeters or inch-pounds) necessary to rotate the pinion gear with a torque wrench. Note the torque for installation reference. It must be known to properly adjust the pinion gear bearing preload torque after seal installation.
(7) Remove the pinion yoke nut and washer. Use
Remover C-452 and Wrench C-3281 to remove the pinion yoke (Fig. 2).
(8) Mark the positions of the yoke and pinion gear for installation alignment reference.
Fig. 3 Seal Removal
INSTALLATION
(1) Apply a light coating of gear lubricant on the lip of pinion seal. Install seal with Installer W-147-E and Handle C-4171 (Fig. 4).
Fig. 2 Pinion Yoke Removal
Fig. 4 Pinion Seal Installation
(2) Align the reference marks and install yoke on the pinion gear with Installer W-162-D.
(3) Install a new pinion nut on pinion shaft.
Tighten the nut only enough to remove the shaft end play.
2 - 24 FRONT SUSPENSION AND AXLE
J
CAUTION: Never loosen the pinion gear nut to decrease the pinion gear bearing preload torque. If the specified preload torque is exceeded, a new collapsible spacer must be installed. The torque sequence will have to be repeated.
(4) Install a socket and inch-pound torque wrench on the pinion nut.
(5) Rotate the shaft with the torque wrench and note the torque.
Required preload torque is the amount recorded during removal plus an additional 0.56
N z m (5 in. lbs.).
(6) Use Flange Wrench C-3281 to retain the yoke and shaft (Fig. 5). Tighten the shaft nut in very small increments.
(7) Continue tightening the shaft nut in small increments until the correct bearing preload torque is attained.
(8) Align the installation reference marks and attach the propeller shaft to the yoke.
(9) Add API grade GL 5 hypoid gear lubricant to the differential housing, if necessary.
(10) Install wheel and tire assemblies.
(11) Remove support and lower the vehicle.
HUB BEARING AND AXLE SHAFT
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the wheel and tire assembly.
(3) Remove the brake components from the axle, refer to Group 5, Brakes.
(4) Remove the cotter pin, nut retainer and axle hub nut (Fig. 6).
Fig. 5 Tightening Pinion Shaft Nut
(5) Remove the hub to knuckle bolts (Fig. 6). Remove the hub from the steering knuckle and axle shaft.
(6) Remove the disc brake rotor shield from the bearing carrier (Fig. 6).
(7) On disconnect axles, remove vacuum shift motor housing. Refer to Vacuum Disconnect Axle in this section.
(8) Remove the axle shaft from the housing. Avoid damaging the axle shaft oil seals in the differential.
Fig. 6 Hub, Knuckle and Axle Shaft
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FRONT SUSPENSION AND AXLE 2 - 25
INSTALLATION
(1) Thoroughly clean the axle shaft (Fig. 6) and apply a thin film of Mopar Wheel Bearing Grease to the shaft splines, seal contact surface, hub bore.
(2) Install the axle shaft into the housing and differential side gears. Avoid damaging the axle shaft oil seals in the differential.
(3) Install the hub bearing and brake dust shield to the knuckle.
(4) Install the hub to knuckle bolts and tighten to
102 N z m (75 ft. lbs.) torque.
(5) Install the hub washer and nut. Tighten the hub nut to 237 N z m (175 ft. lbs.) torque. Install the nut retainer and a new cotter pin (Fig. 6).
(6) Install the brake components, refer to Group 5,
Brakes.
(7) Install the wheel and tire assembly.
(8) Remove support and lower the vehicle.
(2) Locate a socket that is larger in diameter than the bearing cap. Place the socket (receiver) against the yoke and around the perimeter of the bearing cap to be removed. Locate a socket that is smaller in diameter than the bearing cap. Place the socket (driver) against the opposite bearing cap. Position the yoke with the sockets in a vise (Fig. 8).
AXLE SHAFT— CARDAN U-JOINT
DISASSEMBLY
Single cardan U-joints are not serviceable. If defective, they must be replaced as a unit. If the bearings, seals, spider or bearing caps are damaged or worn, replace the complete U-joint.
CAUTION: Clamp only the forged portion of the yoke in the vise. Also, to avoid distorting the yoke, do not over tighten the vise jaws.
(1) Remove the bearing cap retaining snap rings
(Fig. 7).
Fig. 7 Axle Shaft Outer U-Joint
It can be helpful to saturate the bearing caps with penetrating oil prior to removal.
Fig. 8 Yoke Bearing Cap Removal
(3) Compress the vise jaws to force the bearing cap into the larger socket (receiver).
(4) Release the vise jaws. Remove the sockets and bearing cap that was partially forced out of the yoke.
(5) Repeat the above procedure for the remaining bearing cap.
(6) Remove the remaining bearing cap, bearings, seals and spider from the propeller shaft yoke.
CLEANING AND INSPECTION
(1) Clean all the U-joint yoke bores with cleaning solvent and a wire brush. Ensure that all the rust and foreign matter are removed from the bores.
(2) Inspect the yokes for distortion, cracks and worn bearing cap bores.
(3) Replace the complete U-joint if any of the components are defective.
ASSEMBLY
(1) Pack the bearing caps 1/3 full of wheel bearing lubricant. Apply extreme pressure (EP), lithium-base lubricant to aid in installation.
(2) Position the spider in the yoke. Insert the seals and bearings. Tap the bearing caps into the yoke bores far enough to hold the spider in position.
2 - 26 FRONT SUSPENSION AND AXLE
(3) Place the socket (driver) against one bearing cap. Position the yoke with the socket wrench in a vise.
(4) Compress the vise to force the bearing caps into the yoke. Force the caps enough to install the retaining clips.
(5) Install the bearing cap retaining clips.
(6) Install the axle shaft, refer to Hub Bearing and
Axle Shaft installation.
VACUUM DISCONNECT AXLE — YJ VEHICLES
VACUUM CONTROL SYSTEM
The disconnect axle control system consists of;
• Vacuum control switch on the transfer case
• Air vent filter
•
Shift motor
•
Indicator switch
•
Vacuum switch
•
Check valve
•
Vacuum harness (Fig. 9, 10)
Refer to Group 21—Transmissions for additional information involving the Command-Trac
System Transfer Case.
Fig. 9 Vacuum Control System
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Fig. 10 Vacuum Hose Routing
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FRONT SUSPENSION AND AXLE 2 - 27
DISCONNECT AXLE/SHIFT MOTOR DIAGNOSIS
2 - 28 FRONT SUSPENSION AND AXLE
DISCONNECT AXLE/SHIFT MOTOR DIAGNOSIS (CONT’D)
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FRONT SUSPENSION AND AXLE 2 - 29
SHIFT MOTOR — REMOVAL/DISASSEMBLY
(1) Disconnect the vacuum and wiring connector from the shift housing.
(2) Remove indicator switch.
(3) Remove the shift motor housing cover, gasket and shield from the housing (Fig. 11).
Fig. 11 Shift Motor Housing and Shift Collar
(4) Remove the E-clips from the shift motor housing and shaft. Remove shift motor and shift fork from the housing (Fig. 12).
(3) Install the E-clips on the shift motor shaft and housing.
(4) Install the shift motor housing gasket and cover. Ensure the shift fork is correctly guided into the shift collar groove.
(5) Install the shift motor housing shield and attaching bolts. Tighten the bolts to 11 N z m (101 in.
lbs.) torque.
(6) Add 148 ml (5 ounces) of API grade GL 5 hypoid gear lubricant to the shift motor housing. Add lubricant through indicator switch mounting hole.
(7) Install indicator switch, electrical connector and vacuum harness.
INTERMEDIATE AXLE SHAFT—REMOVAL/
DISASSEMBLY
Service to the Disconnect axle seals and bearing require the use of Tool Set 6288 (J34659) and Seal Installer 6228.
(1) Remove the vacuum motor housing. Refer to
Shift Motor Removal in this section.
(3) Remove the outer axle shaft. Refer to Hub
Bearing and Axle Shaft in this section.
(4) Remove shift collar and intermediate axle shaft.
(5) Remove the inner axle shaft seal from the shift motor housing (Fig. 13).
Fig. 12 Vacuum Shift Motor Components
(5) Remove the O-ring seal from the shift motor shaft.
(6) Clean and inspect all components. If any component is excessively worn or damaged, it should be replaced.
ASSEMBLY/INSTALLATION
(1) Install a new O-ring seal on the shift motor shaft.
(2) Insert the shift motor shaft through the hole in the housing and shift fork. The shift fork offset should be toward the differential.
Fig. 13 Axle Shaft Inner Seal Removal
(6) Remove the intermediate axle shaft bearing
(Fig. 14).
ASSEMBLY/INSTALLATION
(1) Position the bearing on installation tool. Seat the bearing in the housing bore (Fig. 15).
(2) Clean the inside perimeter of the axle shaft tube with fine crocus cloth.
(3) Apply a light film of oil to the inside lip of the new axle shaft seal.
(4) Install the inner axle seal (Fig. 16, 17).
The axle shaft seal primary installation tool
6228-1 will only force the seal partially into the
2 - 30 FRONT SUSPENSION AND AXLE
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Fig. 14 Bearing Removal Tool Installed
Fig. 17 Secondary Installation of Seal (Step Two)
(5) Insert the intermediate axle shaft into the differential side gear.
(6) Install the shift collar on the splined end of the intermediate axle shaft.
(7) Lubricate the splined end of the intermediate axle shaft with multi-purpose lubricant (Fig. 18).
Fig. 15 Intermediate Shaft Bearing Installation axle shaft tube bore. The axle shaft seal secondary installation tool 6228-3 must be used to completely seat the seal in the axle shaft tube bore.
After seal installation, inspect that the seal is
NOT distorted or cocked in the tube.
Fig. 16 Primary Installation of Seal (Step One)
Fig. 18 Shift Collar Installation
CAUTION: Apply all-purpose lubricant to the axle shaft splines to prevent damage to the seal during axle shaft installation.
(8) Insert the axle shaft into the tube. Engage the splined-end of the shaft with the shift collar. Refer to
Hub Bearing and Axle Shaft in this section.
(9) Install the vacuum motor housing. Refer to
Shift Motor Installation in this section.
STEERING KNUCKLE AND BALL STUDS
Ball Stud service procedures below require removal of the hub bearing and axle shaft. Removal and installation of upper and lower ball stud requires use of Tool Kit 6289 (J34503-A).
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FRONT SUSPENSION AND AXLE 2 - 31
Fig. 19 Steering Knuckle Removal/Installation
The lower ball stud has two different designs. For this reason installer 6752 will also be needed. Check installers for proper fit.
KNUCKLE REMOVAL
(1) Remove hub bearing and axle shaft refer to the
Removal procedure.
(2) Disconnect the tie-rod or drag link end from the steering knuckle arm. Remove the ABS sensor wire and bracket from knuckle.
(3) Remove the cotter pins from the upper and lower ball studs. Remove the upper and lower ball stud nuts.
(4) Strike the steering knuckle with a brass hammer to loosen. Remove knuckle from axle tube yokes
(Fig. 19).
UPPER BALL STUD REPLACEMENT
(1) Position tools as shown to remove and install ball stud (Fig. 20).
LOWER BALL STUD REPLACEMENT
(1) Position tools as shown to remove and install ball stud (Fig.21). Because there are two different designs for the lower ball studs try both installers for proper fit.
KNUCKLE INSTALLATION
(1) Position the steering knuckle on the ball studs.
(2) Install and tighten the bottom retaining nut to
109 N z m (80 ft. lbs.) torque. Install new cotter pins.
(3) Install and tighten the top retaining nut to 101
N z m (75 ft. lbs.) torque. Install new cotter pin.
Fig. 20 Upper Ball Stud Remove/Install
2 - 32 FRONT SUSPENSION AND AXLE
J
Fig. 21 Lower Ball Stud Remove/Install
(4) Install the Hub Bearing and Axle Shaft according to the installation procedure.
(5) Reconnect the tie-rod or drag link end onto the steering knuckle arm. Install the ABS sensor wire and bracket to the knuckle, refer to Group 5 —
Brakes.
AXLE BUSHING REPLACEMENT
Refer to Axle Bushing Replacement in the Front
Suspension section.
DIFFERENTIAL REMOVAL
To service the differential the axle assembly and axle shafts must be removed. Refer to the removal procedures in this Group.
(1) Note the installation reference letters stamped on the bearing caps and housing machined sealing surface (Fig. 22).
(2) Remove the differential bearing caps.
(3) Position Spreader W-129-B with the tool dowel pins seated in the locating holes (Fig. 23). Install the holddown clamps and tighten the tool turnbuckle finger-tight.
(4) Install a pilot stud at the left side of the differential housing. Attach Dial Indicator to housing pilot stud. Load the indicator plunger against the opposite side of the housing (Fig. 26) and zero the indicator.
CAUTION:Do not spread over 0.38 mm (0.015 in). If
Fig. 22 Bearing Cap Identification the housing is over-separated, it could be distorted or damaged.
(5) Separate the housing enough to remove the case from the housing. Measure the distance with the dial indicator (Fig. 23).
(6) Remove the dial indicator.
(7) Pry the differential case loose from the housing. To prevent damage, pivot on housing with the end of the pry bar against spreader (Fig. 24).
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FRONT SUSPENSION AND AXLE 2 - 33
Fig. 23 Spread Differential Housing
Fig. 25 Axle Seal Installation
(2) Install the inner axle seal on Tool 6228-1 (Fig.
26).
(3) Thread the reverse side of Installer 6228-1 tightly onto the threaded rod tool (Fig. 26).
(4) Press the seal into position.
Fig. 24 Differential Removal
(8) Remove the case from housing. Mark or tag bearing cups indicating which side they were removed. Remove spreader from housing.
INNER AXLE SHAFT OIL SEAL REPLACEMENT
SELECT-TRAC
(1) Remove the inner axle shaft seals with a pry bay.
(2) Install oil seals with Discs 6764 and Turnbuckle D-112-A (Fig. 25). Tighten tool until disc bottoms in housing.
COMMAND-TRAC— LEFT-SIDE
(1) Remove the inner axle shaft seal with a pry bay.
Fig. 26 Left Side Seal Installation
2 - 34 FRONT SUSPENSION AND AXLE
Fig. 28 Ring Gear Removal
Fig. 27 Differential Bearing Removal
DIFFERENTIAL DISASSEMBLY
(1) Remove the bearings from the differential case with Press C-293-PA, Plug C-293-3, Adapter
C-293-39 (Fig. 27).
Place adapter rings so they do not damage the bearing cage.
(2) Remove bearing shims from case hubs and mark them (with hub identity) for assembly reference. Record the thickness of the shims.
(3) Clamp the differential case in a vise equipped with soft jaws. Remove and discard the ring gear bolts. Tap the ring gear with a rawhide or plastic mallet and remove (Fig. 28).
(4) Use a drift to remove the pinion gear mate shaft lock pin (Fig. 29).
(5) Remove the mate shaft with a drift and hammer (Fig. 30).
(6) Rotate the differential side gears and remove the pinion mate gears and thrust washers (Fig. 31).
(7) Remove the differential side gears and thrust washers.
(8) Remove the case from the vise.
PINION REMOVAL/DISASSEMBLY
(1) Remove the pinion yoke nut and washer. Use
Remover C-452 and Wrench C-3281 to remove the pinion yoke (Fig. 32).
Fig. 29 Mate Shaft Lock Pin Removal
Fig. 30 Mate Shaft Removal
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FRONT SUSPENSION AND AXLE 2 - 35
Fig. 31 Pinion Mate Gear Removal
Fig. 33 Remove Pinion Gear
Fig. 32 Pinion Yoke Removal
(2) Remove the pinion gear seal with a slide hammer or pry out with bar.
(3) Drive out pinion gear from housing with rawhide or plastic hammer (Fig. 33). Catch the pinion with your hand to prevent it from falling and being damaged. This will damage the front bearing roll- ers and bearing cup. The front bearing and cup
must be replaced. Remove and discard collapsible preload spacer (Fig. 34).
(4) Remove front bearing from housing.
(5) Remove the front pinion bearing cup with Remover D-147 and Handle C-4171 (Fig. 35).
(7) Remove the rear bearing cup from housing
(Fig. 36). Use Remover D-149 and Handle C-4171.
(8) Remove the inner bearing from the pinion with
Puller C-293-PA and Adapter C-293-39 (Fig. 37).
Fig. 34 Collapsible Preload Spacer
Place adapter rings so they do not damage the bearing cage.
(9) Remove the oil slinger from the pinion gear shaft. Save the slinger it is used as select shim for pinion depth.
CLEANING/INSPECTION
Wash differential components with cleaning solvent and dry with compressed air. Do not steam clean the differential components.
2 - 36 FRONT SUSPENSION AND AXLE
J
Fig. 35 Front Bearing Cup Removal
Fig. 36 Rear Bearing Cup Removal
Wash bearings with solvent and towel dry, do not dry with compressed air. Cup and bearing must be replaced as a matched sets only.
Clean the axle shaft tubes with a clean cloth.
Inspect for;
• Smooth appearance with no broken/dented surfaces on the bearing rollers or the roller contact surfaces.
•
Bearing cups must not be distorted or cracked.
• Machined surfaces should be smooth and without any raised edges.
• Raised metal on shoulders of cup bores should be removed with a hand stone.
Fig. 37 Inner Bearing Removal
• Wear or damage to pinion gear mate shaft, pinion gears, side gears and thrust washers. Replace as a matched set only.
• Worn or chipped teeth to ring and pinion gears.
•
Damaged bolt threads to ring gear. Replaced as a matched set only.
• Pinion yoke for cracks, worn splines, pitted areas, and a rough/corroded seal contact surface. Repair or replace the as necessary.
DIFFERENTIAL ASSEMBLY
ASSEMBLY
(1) Install the following components in the differential case (Fig. 38).
• Differential side gears and thrust washers
•
Pinion gears and thrust washers
• Pinion gear mate shaft (align holes in shaft and case)
(2) Install and seat the locking roll pin in the differential case and mate shaft with a punch and hammer (Fig. 38). Peen metal part of case over pin in two places 180 degrees apart.
If replacement gears and thrust washers were installed, it is not necessary to measure the gear backlash. Correct fit is due to close machining tolerances during manufacture.
(3) Invert the differential case and start two ring gear bolts. This will provide case-to-ring gear bolt hole alignment.
(4) Install new ring gear bolts and alternately tighten to 95-122 N z m (70-90 ft. lbs.) torque (Fig. 39).
(5) Lubricate all differential components with hypoid gear lubricant.
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FRONT SUSPENSION AND AXLE 2 - 37
pinion is 92.1 mm (3.625 inches) for Model 30 axles
(Fig. 41). The standard depth provides the best teeth contact pattern.
Fig. 38 Mate Shaft Pin Installation
Fig. 40 Pinion Gear ID Numbers
THE BUTTON END ON THE PINION GEAR
HEAD IS NO LONGER A MACHINED-TO-SPECI-
FICATIONS SURFACE. DO NOT USE THIS SUR-
FACE FOR PINION DEPTH SET-UP OR
CHECKING (Fig. 41).
Fig. 39 Ring Gear Bolt Installation
PINION GEAR DEPTH INFORMATION
Ring and pinion gears are supplied as matched sets only. The identifying numbers for the ring and pinion gear are etched into the face of each gear (Fig.
40). A plus (+) number, minus (-) number or zero (0) is etched into the face of the pinion gear. This number is the amount (in thousandths of an inch) the depth varies from the standard depth setting of a pinion etched with a (0). The standard setting from the centerline of the ring gear to the back face of the
Fig. 41 Pinion Gear Head
Compensation for depth variance is achieved by a selected thickness oil slinger (production) or shims
(service). The slinger is placed between the inner pinion bearing cone and gear head (Fig. 42). The shim pack is placed under the inner (rear) bearing cup for service. To change the pinion adjustment, shims are available in thicknesses of 0.003, 0.005, and 0.010 inch. The oil slinger or baffle must be measured and the thickness included with the total shim pack.
New gear set: note the depth variance etched into both the original and the replacement pinion gear. Add or subtract the thickness of the
2 - 38 FRONT SUSPENSION AND AXLE
J new pinion is (-) 2, intersecting figure is (-)0.001 inch
(0.025mm). Subtract this amount from original shim.
Refer to the Pinion Gear Depth Variance Chart.
DIFFERENTIAL AND PINION MEASUREMENT
Fig. 42 Shim Locations original depth shims to compensate for the difference in the depth variances. Refer to the
Depth Variance charts.
Note where Old and New Pinion Marking columns intersect. Intersecting figure represents plus or minus amount needed.
For example, if old pinion is plus (+) 1 and the new pinion is minus (-) 3, intersecting figure is
(+)0.004 inch (0.10mm). Add this amount to the original shim. Or if the old pinion is (-) 3 and the
DIFFERENTIAL ZERO END PLAY
MEASUREMENT
(1) Place Master Differential Bearing D-134
(D-348) on the case hubs (Fig. 43) and install differential case into housing.
(2) Install a pilot stud at the right side of housing.
Attach Dial Indicator to the pilot stud. Load indicator plunger against the back of the ring gear (Fig.
44).
(3) Insert a small pry bar between the bearing cap and left side of differential case. Pry the case as far as possible to right side (Fig. 44). Zero the dial indicator pointer.
(4) Pry the case to left side and record the travel distance.
The measurement above is the shim thickness necessary for case zero end-play. The total thickness will be determined during the ring gear backlash adjustment.
(5) Remove indicator, pilot stud and differential case from housing.
PINION GEAR DEPTH MEASUREMENT
Pinion gear depth measurement is necessary when axle housing is replaced or pinion select shim pack is unknown. It is also recommended when ring and pinion gears are replaced.
PINION GEAR DEPTH VARIANCE
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FRONT SUSPENSION AND AXLE 2 - 39
Fig. 43 Master Bearing Tools On Hubs Fig. 45 Pinion Gear Depth Gauge Tools
Fig. 46 Pinion Height Block
Fig. 44 Differential Case End Play Measurement
Measurements are done with pinion cups and pinion bearings installed in housing. Take measurements with Pinion Gauge Set 6774, Pinion Block
6733 and Dial Indicator C-3339 (Fig. 45).
(1) Assemble Pinion Gauge Set, Pinion Block and pinion bearings. Install assembly into differential pinion gear bore and hand tighten cone (Fig. 46).
(2) Place Arbor Disc 6732 on Arbor D-115-3 and position in the bearing cradles (Fig. 47). Install differential bearing caps on Arbor Discs and tighten caps snug only.
Fig. 47 Gauge Tools In Housing
2 - 40 FRONT SUSPENSION AND AXLE
J
Arbor Discs have different steps to fit other axle sizes. Pick correct size step for axle being serviced.
(3) Firmly place Scooter Block and Dial Indicator on pinion height block tool and zero the dial indicator pointer.
(4) Slide the Scooter Block across the arbor while observing indicator (Fig. 48). Record the longest travel distance, whether inward (-) or outward (+), indicated by the pointer.
The plunger travel distance indicated, plus or minus the variance etched in the gear is the required thickness for the depth shims.
(5) Measure the thickness of each depth shim with a micrometer and combine the shims necessary for total required shim pack thickness. Include oil slinger or baffle thickness with the total shim pack thickness.
(6) Remove the measurement tools from the differential housing.
PINION GEAR ASSEMBLY/INSTALLATION
(1) Place the shims (and baffle if equipped) in the pinion gear rear bearing bore. Install the bearing cup with Installer D-146 and Driver Handle C-4171 (Fig.
49). Ensure cup is correctly seated.
(2) Install the pinion front bearing cup with Installer D-144 and Handle C-4171 (Fig. 50).
Fig. 48 Pinion Depth Measurement
Fig. 50 Pinion Front Bearing Cup Installation
(3) Install the rear bearing and oil slinger on the pinion gear with Installer W-262 until completely seated (Fig. 51).
Fig. 49 Pinion Rear Bearing Cup Installation Fig. 51 Pinion Rear Bearing Installation
J
(4) Assemble collapsible spacer onto pinion shaft
(Fig. 52).
FRONT SUSPENSION AND AXLE 2 - 41
Fig. 52 Collapsible Preload Spacer
(5) Install pinion front bearing cone into cup and end yoke thrust washer.
(6) Apply a light coat of gear lubricant on lip of new pinion seal. Install seal with Installer W-147-E and Handle C-4171 (Fig. 53).
(7) Install pinion gear into differential housing.
Fig. 54 Pinion Yoke Installation
(9) Install the yoke washer and a new nut on the pinion gear. Use Flange Wrench C-3281 to retain the yoke (Fig. 55). Tighten nut to 216 N z m (160 ft.lbs.) torque or enough to remove play. Do not over-
tighten.
Fig. 53 Pinion Seal Installation
(8) Install yoke with Installer W-162-D and
Wrench C-3281 (Fig. 54).
Fig. 55 Tightening Pinion Nut
CAUTION: Never loosen the pinion gear nut to decrease the pinion gear bearing preload torque. If the specified preload torque is exceeded, a new collapsible spacer must be installed. The torque sequence will have to be repeated.
2 - 42 FRONT SUSPENSION AND AXLE
(10) Use Flange Wrench C-3281 to retain the yoke
(Fig. 55). Slowly tighten the nut in small increments until the rotating torque is achieved. Measure the rotating torque frequently to avoid over-tightening the nut.
(11) Check bearing rotating torque with an inch pound torque wrench (Fig. 56). The torque necessary to rotate the pinion gear should be;
J
Fig. 57 Shim Pack Measurement
Fig. 56 Check Pinion Gear Torque
• Original Bearings — 1 to 3 N z m (10 to 20 in. lbs.).
• New Bearings — 2 to 5 N z m (15 to 35 in. lbs.).
DIFFERENTIAL SHIM PACK MEASUREMENT AND
ADJUSTMENT
(1) Place Master Differential Bearing D-134
(D-348) on the case hubs.
(2) Install a pilot stud at the left side of housing.
Attach Dial Indicator to housing. Load the indicator plunger against the back of the ring gear (Fig. 57).
Ensure ring and pinion gear teeth are tightly meshed. Zero the indicator.
(3) Insert a small pry bar between the bearing cap and left side of differential case. Pry the case as far as possible to right side (Fig. 57). Zero the dial indicator pointer.
(4) Repeat the measurement several times to check consistency. Record the travel distance.
The measurement above shows shim thickness necessary to eliminate ring gear backlash. Subtract this thickness from case zero end-play shim thickness (Fig. 58). The shims must be placed at the ring gear side between the case and bearing.
(5) Remove indicator and pilot stud.
(6) Remove the differential case from housing.
Fig. 58 Shim Pack Calculations
(7) Remove the master bearing tools from the differential case hubs.
(8) Position the backlash shims (with determined thickness) on case hub (ring gear side). Install bearing on the hub with Bearing Installer C-3716-A and
Driver Handle C-4171 (Fig. 59).
(9) Position the remaining zero end-play shims on hub at opposite side of case. Include an additional
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FRONT SUSPENSION AND AXLE 2 - 43
stud. Load the indicator plunger against the opposite side of the housing (Fig. 60) and zero the indicator.
CAUTION: Do not spread over 0.38 mm (0.015 in). If the housing is over-separated, it could be distorted or damaged.
(3) Spread the housing enough to install the case in the housing. Measure the distance with the dial indicator (Fig. 60).
(4) Remove the dial indicator.
(5) Install case in the housing. Tap the differential case to ensure the bearings are fully seated (Fig. 61).
Remove the spreader.
Fig. 59 Differential Bearing Installation
0.015 in. (0.38 mm) thick shim on this hub. This will provide the required differential bearing preload torque.
(10) Install bearings on hubs with Installer
C-3716-A and Handle C-4171 (Fig. 59).
(11) Match each bearing cup with bearing (original). Install the cups on the bearings.
DIFFERENTIAL INSTALLATION
(1) Position Spreader W-129-B with the tool dowel pins seated in the locating holes (Fig. 60). Install the holddown clamps and tighten the tool turnbuckle finger-tight.
Fig. 61 Differential Installation
(6) Install the bearing caps at their original locations (Fig. 62). Tighten the bearing cap bolts to 61
N z m (45 ft. lbs.) torque.
Fig. 60 Spread Differential Housing
(2) Install a pilot stud at the left side of the differential housing. Attach Dial Indicator to housing pilot
Fig. 62 Differential Bearing Cap Reference Letters
2 - 44 FRONT SUSPENSION AND AXLE
J
BACKLASH AND CONTACT PATTERN ANALYSIS
(1) Rotate assembly several revolutions to seat bearings. Measure backlash at three equally spaced locations around the perimeter of the ring gear with a dial indicator (Fig. 63).
If the mesh and backlash steps have been followed in the procedures above, good gear teeth contact patterns should exist.
The ring gear teeth contact patterns will show if the pinion gear depth is correct. It will also show if the ring gear backlash has been adjusted correctly.
The backlash must be maintained within the specified limits until the correct tooth contact patterns are obtained.
(2) Apply a thin coat of hydrated ferric oxide (yellow oxide of iron) to the drive and coast side of the ring gear teeth.
(3) Rotate the ring gear one complete revolution in both directions while a load is being applied. Insert a pry bar between the differential housing and the case flange. This action will produce distinct contact patterns on both the drive side and coast side of the ring gear teeth.
(4) Note patterns in compound. Refer to (Fig. 65) for interpretation of contact patterns and adjust accordingly.
Fig. 63 Ring Gear Backlash Measurement
The ring gear backlash must be within 0.005 -
0.008 inch (0.12 - 0.20 mm). It cannot vary more than 0.002 inch (0.05 mm) between the points checked.
If backlash must be adjusted, transfer shims from one side of carrier to the other side. Adjust the backlash accordingly (Fig. 64). DO NOT INCREASE
THE TOTAL SHIM PACK THICKNESS, EXCES-
SIVE BEARING PRELOAD AND DAMAGE
WILL OCCUR.
FINAL ASSEMBLY
(1) Install the axle shafts. Refer to Axle Shaft Installation in this Group.
(2) Scrape the residual sealant from the housing and cover mating surfaces. Clean the mating surfaces with mineral spirits. Apply a bead of MOPAR t
Silicone Rubber Sealant on the housing cover (Fig.
66). Allow the sealant to cure for a few minutes.
Install the housing cover within 5 minutes after applying the sealant. If not installed the sealant must be removed and another bead applied.
(3) Install the cover on the differential with the attaching bolts. Install the identification tag. Tighten the cover bolts with 41 N z m (30 ft. lbs.) torque.
CAUTION: Overfilling the differential can result in the lubricant foaming and overheating.
(4) Refill the differential housing with the specified quantity of MOPAR t Hypoid Gear Lubricant.
(5) Install the fill hole plug and tighten to 34 N z m
(25 ft. lbs.) torque.
Fig. 64 Backlash Shim Adjustment
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FRONT SUSPENSION AND AXLE 2 - 45
Fig. 65 Gear Tooth Contact Patterns
2 - 46 FRONT SUSPENSION AND AXLE
Fig. 66 Typical Housing Cover With Sealant
AXLE SPECIFICATIONS
MODEL 30 FRONT AXLE
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FRONT SUSPENSION AND AXLE 2 - 47
TORQUE SPECIFICATIONS
YJ FRONT SUSPENSION COMPONENTS
XJ FRONT SUSPENSION COMPONENTS
MODEL 30 AXLE
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FUEL SYSTEM 14 - 1
FUEL SYSTEM
ACCELERATOR PEDAL AND THROTTLE CABLE
FUEL DELIVERY SYSTEM
GENERAL INFORMATION
CONTENTS page
. . . 16
. . . . . . . . . . . . . . . . . 2
FUEL TANKS . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
. . . . . . . . . . . . . . . . . . 1
MULTI-PORT FUEL INJECTION (MFI)—COMPO-
NENT DESCRIPTION/SYSTEM OPERATION
. 17
page
MULTI-PORT FUEL INJECTION (MFI)—
COMPONENT REMOVAL/INSTALLATION
. . . 54
MULTI-PORT FUEL INJECTION (MFI)—
GENERAL DIAGNOSIS
. . . . . . . . . . . . . . . . . . 32
SPECIFICATIONS
. . . . . . . . . . . . . . . . . . . . . . . 62
GENERAL INFORMATION
Throughout this group, references are made to particular vehicle models by alphabetical designation or by the particular vehicle nameplate. A chart showing a breakdown of the alphabetical designations is included in the Introduction section at the beginning of this manual.
The Fuel System consists of: the fuel tank, an electric (fuel tank mounted) fuel pump and a fuel filter. It also consists of fuel tubes/lines/hoses, vacuum hoses, throttle body and fuel injectors.
The Fuel Delivery System consists of: the electric fuel pump, fuel filter, fuel tubes/lines/hoses, fuel rail, fuel injectors and fuel pressure regulator.
A Fuel Return System is used on all vehicles.
The system consists of: the fuel tubes/lines/hoses that route fuel back to the fuel tank.
The Fuel Tank Assembly consists of: the fuel tank, filler tube, fuel gauge sending unit/electric fuel pump module, a pressure relief/rollover valve and a pressure-vacuum filler cap.
Also to be considered part of the fuel system is the
Evaporation Control System. This is designed to reduce the emission of fuel vapors into the atmosphere. The description and function of the Evaporative Control System is found in Group 25, Emission
Control Systems.
FUEL USAGE STATEMENT
Your vehicle was designed to meet all emission regulations and provide excellent fuel economy using high quality unleaded gasoline. Only use unleaded gasolines having a minimum posted octane of 87.
If your vehicle develops occasional light spark knock (ping) at low engine speeds, this is not harmful. However, continued heavy knock at high speeds can cause damage and should be re-
ported to your dealer immediately. Engine damage as a result of heavy knock operation may not be covered by the new vehicle warranty.
In addition to using unleaded gasoline with the proper octane rating, those that contain deter- gents, corrosion and stability additives are recommended.
Using gasolines that have these additives will help improve fuel economy, reduce emissions and maintain vehicle performance. Generally, premium unleaded gasolines contain more additive than regular unleaded gasolines.
Poor quality gasoline can cause problems such as hard starting, stalling and stumble. If you experience these problems, use another brand of gasoline before considering service for the vehicle.
GASOLINE/OXYGENATE BLENDS
Some fuel suppliers blend unleaded gasoline with materials that contain oxygen such as alcohol, MTBE and ETBE. The type and amount of oxygenate used in the blend is important. The following are generally used in gasoline blends:
ETHANOL
Ethanol (Ethyl or Grain Alcohol) properly blended, is used as a mixture of 10 percent ethanol and 90 percent gasoline. Gasoline with ethanol may be used in your vehicle.
METHANOL
CAUTION: DO NOT USE GASOLINES CONTAINING
METHANOL. Use of methanol/gasoline blends may result in starting and driveability problems. In addition, damage may be done to critical fuel system components.
Methanol (Methyl or Wood Alcohol) is used in a variety of concentrations blended with unleaded gaso-
14 - 2 FUEL SYSTEM
J line. You may encounter fuels containing 3 percent or more methanol along with other alcohols called cosolvents.
Problems that are the result of using methanol/gasoline blends are not the responsibility of Chrysler
Corporation. They may not be covered by the vehicle warranty.
MTBE/ETBE
Gasoline and MTBE (Methyl Tertiary Butyl Ether) blends are a mixture of unleaded gasoline and up to
15 percent MTBE. Gasoline and ETBE (Ethyl Tertiary Butyl Ether) are blends of gasoline and up to
17 percent ETBE. Gasoline blended with MTBE or
ETBE may be used in your vehicle.
CLEAN AIR GASOLINE
Many gasolines are now being blended that contribute to cleaner air, especially in those areas of the country where air pollution levels are high. These new blends provide a cleaner burning fuel and some are referred to as Reformulated Gasoline.
In areas of the country where carbon monoxide levels are high, gasolines are being treated with oxygenated materials such as MTBE, ETBE and ethanol.
Chrysler Corporation supports these efforts toward cleaner air and recommends that you use these gasolines as they become available.
FUEL DELIVERY SYSTEM
INDEX
page
Fuel Filter
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Fuel Pressure Leak Down Test
. . . . . . . . . . . . . . . 7
Fuel Pressure Release Procedure
Fuel Pump Capacity Test
. . . . . . . . . . . . . . . . . . . 7
Fuel Pump Electrical Control
. . . . . . . . . . . . . . . . . 5
page
Fuel Pump Module
. . . . . . . . . . . . . . . . . . . . . . . . 2
Fuel System Pressure Test
. . . . . . . . . . . . . . . . . . 5
Fuel Tubes/Lines/Hoses and Clamps
Quick-Connect Fittings
. . . . . . . . . . . . . . . . . . . . . 9
FUEL PUMP MODULE
The fuel pump module is installed in the top of the fuel tank. The fuel pump module contains the following components:
•
Electric fuel pump
• Fuel pump reservoir
• In-tank fuel filter
•
Fuel gauge sending unit
• Fuel supply and return tube connections
The fuel pump used on all vehicles is a gear/rotor type pump. It is driven by a permanent magnet 12 volt electric motor that is immersed in the fuel tank.
The electrical pump is integral with the fuel sender unit. The pump/sender assembly is installed inside the fuel tank.
The fuel pump has a check valve at the outlet end that consists of a ball held against a seat by force applied from a spring. When the pump is operating, fuel pressure overcomes spring pressure and forces the ball off its seat, allowing fuel to flow. When the pump is not operating, spring pressure forces the ball back against the seat preventing fuel backflow through the pump.
Fuel system pressure is maintained at approximately 214 kPa (31 psi). This is when the pump is operating and vacuum is supplied to the fuel pressure regulator. If vacuum is not supplied to the pressure regulator, fuel pressure will be approximately
55-69 kPa (8-10 psi) higher. This may be due to a broken or clogged vacuum line. When the fuel pump is not operating, system fuel pressure of 131-269 kPa
(19-39 psi) is maintained. This is done by the fuel pump outlet check valve and the vacuum assisted fuel pressure regulator.
REMOVAL—XJ MODELS
The fuel pump/gauge sender unit assembly can be removed from the fuel tank without removing the tank from the vehicle.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING THE FUEL PUMP MODULE,
THE FUEL SYSTEM PRESSURE MUST BE RE-
LEASED. REFER TO THE FUEL PRESSURE RE-
LEASE PROCEDURE IN THIS GROUP.
WARNING: EXTINGUISH ALL TOBACCO SMOKING
PRODUCTS BEFORE SERVICING THE FUEL SYS-
TEM. KEEP OPEN FLAME AWAY FROM FUEL SYS-
TEM COMPONENTS.
(1) Remove fuel filler cap. Perform the Fuel Pressure Release Procedure as outlined in this group.
(2) Disconnect negative battery cable.
(3) Using an approved portable gasoline siphon/ storage tank, drain fuel tank until fuel level is below one quarter (1/4) full.
(4) Raise and support vehicle.
J
WARNING: WRAP SHOP TOWELS AROUND FUEL
HOSES TO ABSORB ANY FUEL SPILLAGE DURING
FUEL TANK REMOVAL.
(5) Disconnect fuel vent supply and return tubes from fittings on fuel pump module.
(6) Disconnect fuel pump module electrical harness connector from main harness.
(7) Using a brass punch and hammer, remove fuel pump module lock ring by carefully tapping it counterclockwise (Fig. 1).
FUEL SYSTEM 14 - 3
Fig. 1 Removing Lock Ring—XJ Models—Typical
(8) Remove fuel pump module and O-ring seal.
Discard old O-ring and fuel pump module inlet filter.
DISASSEMBLY—XJ MODELS
(1) Remove and discard fuel pump inlet filter.
The wire terminals to the fuel pump motor are different in size and cannot be connected to the wrong terminal.
(2) Disconnect fuel pump terminal wires.
(3) Remove fuel pump outlet hose and clamp. Replace the hose if it shows any signs of fatigue or failure.
(4) Remove fuel pump top mounting bracket nut.
Remove fuel pump (Fig. 2).
ASSEMBLY—XJ MODELS
Whenever the fuel pump is replaced, the fuel pump inlet filter (sock) must also be replaced.
(1) Place fuel pump top mounting bracket over top of pump.
(2) Position fuel pump into lower bracket. Slide stud of top bracket through hole in fuel pump side bracket. Tighten fuel pump top mounting nut.
(3) Install new fuel pump outlet hose. Secure with new clamps.
(4) Connect wire terminals to motor.
(5) Install new fuel pump inlet filter.
Fig. 2 Fuel Pump Module—XJ
Models—Disassemble/Assemble
INSTALLATION—XJ MODELS
Whenever the fuel pump is replaced, the fuel pump inlet filter must also be replaced.
(1) Install new fuel pump inlet filter onto fuel pump.
(2) Install fuel pump module assembly and new Oring seal. The rubber stopper on the end of the fuel return tube of the assembly must be inserted into the cup in the fuel tank reservoir (Fig. 3).
Fig. 3 Fuel Pump Module—XJ Models—Installation
14 - 4 FUEL SYSTEM
J
(3) Using a brass punch and a hammer, install lock ring. Carefully tap lock ring clockwise until it seats against stop on fuel tank.
(4) Connect fuel supply and return hoses to fittings on fuel pump module. Tighten hose clamps.
(5) Connect fuel pump module electrical harness connector to main harness connector.
(6) Lower vehicle.
(7) Fill fuel tank. Install fuel tank cap.
(8) Connect negative battery cable.
(9) Start vehicle and inspect for leaks.
REMOVAL—YJ MODELS
The fuel tank must be removed to remove the fuel pump module.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING THE FUEL PUMP MODULE,
THE FUEL SYSTEM PRESSURE MUST BE RE-
LEASED. REFER TO THE FUEL PRESSURE RE-
LEASE PROCEDURE IN THIS GROUP.
DISASSEMBLY—YJ MODELS
5).
(1) Remove and discard fuel pump inlet filter (Fig.
WARNING: EXTINGUISH ALL TOBACCO SMOKING
PRODUCTS BEFORE SERVICING THE FUEL SYS-
TEM. KEEP OPEN FLAME AWAY FROM FUEL SYS-
TEM COMPONENTS.
(1) Remove negative battery cable.
(2) Remove fuel filler cap. Perform the Fuel Pressure Release Procedure as outlined in this group.
(3) Remove fuel tank. Refer to Fuel Tank Removal—YJ Models.
(4) Remove fuel pump module assembly.
(5) Remove mounting screws. Lift assembly and gasket out of fuel tank. Discard old gasket (Fig. 4).
Fig. 5 Fuel Pump Module—YJ Models
The wire terminals to the fuel pump motor are different in size and cannot be connected to the wrong terminal.
(2) Disconnect fuel pump terminal wires from pump.
(3) Remove fuel pump outlet hose and clamp (Fig.
6). Replace the hose if it shows any signs of fatigue or failure.
(4) Remove fuel pump top mounting bracket nut
(Fig. 6). Remove fuel pump.
Fig. 4 Fuel Pump Module—Remove/Install—YJ
Models
(6) Remove and discard fuel pump inlet filter.
Fig. 6 Fuel Pump Removal/Installation—YJ Models
ASSEMBLY—YJ MODELS
Whenever the fuel pump is replaced, the fuel pump inlet filter (sock) must also be replaced.
(1) Place fuel pump top mounting bracket over top of pump.
(2) Position fuel pump into lower bracket. Slide stud of top bracket through hole in fuel pump side bracket. Tighten fuel pump top mounting nut.
J
FUEL SYSTEM 14 - 5
(3) Install new fuel pump outlet hose. Secure with new clamps.
(4) Connect wire terminals to motor.
(5) Install new fuel pump inlet filter.
INSTALLATION—YJ MODELS
(1) Install a new fuel pump inlet filter.
(2) Install fuel pump module assembly with a new gasket between the assembly and tank. Tighten mounting screws to 2 N z m (18 in. lbs.) torque.
(3) Install fuel tank. Refer to Fuel Tank Installation—YJ Models.
(4) Fill fuel tank. Install fuel tank cap.
(5) Install negative battery cable.
(6) Start vehicle and check for leaks.
FUEL PUMP ELECTRICAL CONTROL
For an electrical operational description of the fuel pump, refer to the MFI System—Component Description/System Operation section of this group. See Automatic Shut Down (ASD) Relay—PCM Output.
For the 1994 model year, the ballast resistor and ballast resistor bypass relay are no longer used to control the fuel pump circuit.
FUEL PRESSURE RELEASE PROCEDURE
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39
PSI). THIS PRESSURE MUST BE RELEASED BE-
FORE SERVICING ANY FUEL SUPPLY OR FUEL RE-
TURN SYSTEM COMPONENT.
(1) Disconnect negative battery cable.
(2) Remove fuel tank filler neck cap to release fuel tank pressure.
WARNING: DO NOT ALLOW FUEL TO SPILL ONTO
THE ENGINE INTAKE OR EXHAUST MANIFOLDS.
PLACE SHOP TOWELS UNDER AND AROUND THE
PRESSURE PORT TO ABSORB FUEL WHEN THE
PRESSURE IS RELEASED FROM THE FUEL RAIL.
Fig. 7 Pressure Test Port—Typical
(8) After fuel pressure has been released, remove the hose from the test port.
(9) Install protective cap to fuel test port.
FUEL SYSTEM PRESSURE TEST
The fuel system is equipped with a vacuum assisted fuel pressure regulator (Fig. 8). With engine at idle speed, system fuel pressure should be approximately 214 kPa (31 psi) with the vacuum line connected to the regulator. With the vacuum line disconnected from the regulator, fuel pressure should be approximately 269 kPa (39 psi). This is 55-69 kPa
(8-10 psi) higher.
(1) Remove the protective cap at the fuel rail (Fig.
7). Connect the 0-414 kPa (0-60 psi) fuel pressure gauge (from Gauge Set 5069) to test port pressure fitting on fuel rail (Fig. 9).
WARNING: WEAR PROPER EYE PROTECTION
WHEN RELEASING FUEL SYSTEM PRESSURE.
(3) Remove protective cap from pressure test port on the fuel rail (Fig. 7).
(4) Obtain the fuel pressure gauge/hose assembly from fuel pressure gauge tool set 5069. Remove the gauge from the hose.
(5) Place one end of hose (gauge end) into an approved gasoline container.
(6) Place a shop towel under the test port.
(7) To release fuel pressure, screw the other end of hose onto the fuel pressure test port.
Fig. 8 Fuel Pressure Regulator—Typical
(2) Note pressure gauge reading. Fuel pressure should be approximately 214 kPa (31 psi) at idle.
14 - 6 FUEL SYSTEM
J
Fig. 9 Fuel Pressure Test Connection—Typical
(3) Disconnect vacuum line (hose) at fuel pressure regulator (Fig. 8). Note gauge reading. With vacuum line disconnected, fuel pressure should rise to approximately 269 kPa (39 psi).
Fuel pressure should be approximately 55-69 kPa
(8-10 psi) higher with vacuum line removed from regulator. If not, inspect pressure regulator vacuum line for leaks, kinks or blockage. If vacuum line checks OK and fuel pressure does not rise approximately 8-10 psi after disconnecting vacuum line, replace fuel pressure regulator.
The fuel pressure regulator is not adjustable.
(4) If fuel pressure exceeds 45 psi, check fuel return line/tube for kinks or obstructions.
If the previous tests checked good, fuel pump pressure is correct. If pump pressure was low, proceed as follows:
(5) Release fuel system pressure. Refer to the previous Fuel Pressure Release Procedure in this group.
(6) Disconnect the 5/16 inch fuel return line quickconnect fitting at fuel rail. For procedures, refer to
Fuel Tubes/Lines/Hoses and Clamps. Also refer to
Quick-Connect Fittings. These can be found in the
Fuel Delivery System section of this group.
Connect Fuel Line Pressure Test Adapter Tool number 6539 (5/16 in.) between the disconnected fuel return line and fuel rail (Fig. 10).
WARNING: THE FUEL SYSTEM PRESSURE IN THE
FOLLOWING TEST MAY EXCEED 100 PSI. BEFORE
STARTING TEST, VERIFY GOOD CONNECTIONS AT
ENDS OF ADAPTER TOOL 6539. BE SURE TOOL IS
LOCKED ONTO FUEL RAIL AND FUEL RETURN
LINE. PULL FIRMLY ON ENDS OF TOOL TO VER-
IFY.
(7) To activate the fuel pump and pressurize the system, obtain the DRB scan tool. Refer to the appropriate Powertrain Diagnostic Procedures service manual for DRB operation.
Fig. 10 Adapter Tool—Typical Connection
(8) MOMENTARILY pinch the rubber hose portion of adapter tool 6539. Pressure should rise to approximately 75 psi within two (2) seconds. DO NOT pinch hose for longer than three seconds.
If fuel pump pressure rises to approximately 75 psi within two seconds, pressure is operating at its maximum and is correct.
If fuel pump pressure does not rise to approximately 75 psi within two seconds, proceed as follows:
(9) Release fuel system pressure. Refer to the previous Fuel Pressure Release Procedure in this group.
(10) Raise and support vehicle.
(11) Disconnect fuel supply line at inlet (fuel tank side) of fuel filter. Connect Fuel Line Pressure Test
Adapter Tool number 6631 (3/8 in.) between fuel filter and fuel supply line.
WARNING: THE FUEL SYSTEM PRESSURE IN THE
FOLLOWING TEST MAY EXCEED 100 PSI. BEFORE
STARTING TEST, VERIFY GOOD CONNECTIONS AT
ENDS OF ADAPTER TOOL 6631. BE SURE TOOL IS
LOCKED ONTO FUEL FILTER AND FUEL SUPPLY
LINE. PULL FIRMLY ON ENDS OF TOOL TO VER-
IFY.
(12) To activate the fuel pump and pressurize the system, obtain the DRB scan tool. Refer to the appropriate Powertrain Diagnostic Procedures service manual for DRB operation.
MOMENTARILY pinch the rubber hose portion of adapter tool 6631. Pressure should rise to approximately 75 psi within two (2) seconds. DO NOT pinch hose for longer than three seconds.
If fuel pump pressure now rises to approximately
75 psi within two seconds, but this pressure could not be met at the fuel rail, check for a plugged or restricted fuel filter. Also check the fuel supply line between fuel filter and fuel rail for kinks or obstructions. Proceed to the following Fuel Pump Capacity Test.
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FUEL SYSTEM 14 - 7
FUEL PUMP CAPACITY TEST
Before performing this test, verify fuel pump pressure by performing the previous tests.
(1) Release the fuel system pressure from fuel system. Refer to the previous Fuel Pressure Release
Procedure in this group.
(2) Disconnect the fuel supply line at fuel rail near pressure regulator. For procedures, refer to Fuel
Tubes/Lines/Hoses and Clamps. Also refer to Quick-
Connect Fittings. These can be found in the Fuel Delivery System section of this group.
(3) Connect Fuel Line Pressure Test Adapter Tool number 6631 (3/8 in.) into the disconnected fuel supply line. Insert the other end of tool 6631 into an approved gasoline container.
(4) To activate the fuel pump and pressurize the system, obtain the DRB scan tool. Refer to the appropriate Powertrain Diagnostic Procedures service manual for DRB operation.
A good fuel pump will deliver at least 1 liter of fuel per minute.
FUEL PRESSURE LEAK DOWN TEST
ENGINE OFF
Abnormally long periods of cranking to restart a hot engine that has been shut down for a short period of time may be caused by:
•
Fuel pressure bleeding past the fuel pressure regulator.
• Fuel pressure bleeding past the check valve in the outlet end of the fuel tank mounted fuel pump.
(1) Remove protective cap at fuel rail test port
(Fig. 11). With the engine off, connect an accurate
0-689 kPa (0-100 psi) fuel gauge to the pressure test port fitting on the fuel rail. The fitting on the pressure tester must be in good condition and free of any leaks before performing this test.
(2) Start the vehicle and let engine idle. Check fuel pressure reading on gauge. Fuel pressure should be within specifications. Refer to the previous Fuel
System Pressure Tests.
(3) Shut engine off. Observe and record fuel pressure reading on gauge. Leave fuel pressure gauge connected. Allow engine to set for 30 minutes and then compare the fuel pressure reading on the gauge with the reading taken when engine was shut down.
A pressure drop of up to 138 kPa (20 psi) within 30 minutes is within specifications.
(4) If the fuel pressure drop is within specifications, the fuel pump outlet check valve and fuel pressure regulator are both operating normally.
(5) If fuel pressure drop is greater than 138 kPa
(20 psi), it must be determined if this drop is being caused by (in-tank mounted) fuel pump outlet check valve or fuel pressure regulator. Proceed to next step.
(6) Release the fuel system pressure from fuel system. Refer to the previous Fuel Pressure Release
Procedure in this group.
(7) Disconnect both fuel lines at fuel rail near fuel pressure regulator. For procedures, refer to Fuel
Tubes/Lines/Hoses and Clamps. Also refer to Quick-
Connect Fittings. These can be found in the Fuel Delivery System section of this group.
(8) Connect Fuel Line Pressure Test Adapter Tool number 6631 (3/8 in.) between the disconnected fuel supply line and fuel rail (Fig. 12).
(9) Connect Fuel Line Pressure Test Adapter Tool number 6539 (5/16 in.) between the disconnected fuel return line and fuel rail (Fig. 12).
Fig. 11 Fuel Pressure Test Port—Typical
Fig. 12 Adapter Tools—Typical Connections
(10) Start engine. Observe and record fuel system pressure.
(11) Shut engine off.
(12) Clamp off the rubber hose portion of adapter tool number 6539 connected to the fuel return line.
Allow engine to set for 30 minutes. If pressure has dropped more than 138 kPa (20 psi) in 30 minutes,
14 - 8 FUEL SYSTEM
J pressure is bleeding past the (in-tank mounted) fuel pump outlet check valve. Replace Fuel Pump Module assembly. Refer to Fuel Pump Module removal and installation in this group. If pressure drop is within specifications, proceed to next step.
(13) Clamp off the rubber hose portion of adapter tool number 6631 connected to the fuel supply line.
Allow engine to set for 30 minutes. If pressure has dropped more than 138 kPa (20 psi) in 30 minutes, pressure is bleeding past the fuel pressure regulator.
Replace fuel pressure regulator. Refer to Fuel Rail removal and installation in the Component Removal/
Installation section of this group.
MECHANICAL MALFUNCTIONS
Mechanical malfunctions are more difficult to diagnose with this system. The powertrain control module (PCM) has been programmed to compensate for some mechanical malfunctions such as incorrect cam timing, vacuum leaks, etc. If engine performance problems are encountered and diagnostic trouble codes are not displayed, the problem may be mechanical rather than electronic.
FUEL FILTER
The fuel filter protects the fuel injectors and fuel pressure regulator from dirt, water and other foreign matter. The filter is located under the vehicle along the frame rail (Figs. 13 or 14). Replace fuel filter at intervals specified in the Lubrication and Maintenance Schedule chart found in Group 0, Lubrication and Maintenance.
Fig. 13 Fuel Filter and Shield—YJ Models
REMOVAL
Fig. 14 Fuel Filter—XJ Models
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39
PSI). THIS PRESSURE MUST BE RELEASED BE-
FORE SERVICING THE FUEL FILTER.
(1) Disconnect negative battery cable. Remove fuel filler cap.
WARNING: FUEL PRESSURE MUST BE RELEASED
BEFORE DISCONNECTING ANY FUEL SYSTEM
COMPONENT.
(2) Release fuel system pressure. Refer to Fuel
Pressure Release Procedure in this group.
(3) Raise and support vehicle.
(4) On YJ models remove the fuel filter shield
(Fig. 13).
(5) Remove hoses and clamps from inlet and outlet sides of filter (Figs. 13 or 14). For procedures, refer to
Fuel Tubes/Lines/Hoses and Clamps. Also refer to
Quick-Connect Fittings. These can be found in the
Fuel Delivery System section of this group.
(6) Remove retaining strap bolt.
(7) Remove filter from vehicle.
INSTALLATION
CAUTION: The ends of the fuel filter are marked for correct installation. Install filter with the end marked
IN towards fuel tank and the end marked OUT towards engine.
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FUEL SYSTEM 14 - 9
(1) Place fuel filter in retaining strap with the marked ends in the correct position.
(2) Install retaining strap bolt and tighten to 12
N z m (106 in. lbs.) torque.
(3) Install inlet and outlet hoses and hose clamps.
For procedures, refer to Fuel Tubes/Lines/Hoses and
Clamps. Also refer to Quick-Connect Fittings. These can be found in the Fuel Delivery System section of this group.
(4) On YJ models, install fuel filter shield (Fig. 13).
(5) Lower vehicle.
(6) Connect negative battery cable.
(7) Start engine and check for leaks.
FUEL TUBES/LINES/HOSES AND CLAMPS
Also refer to the proceeding section on Quick-Connect Fittings.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
Inspect all hose connections such as clamps, couplings and fittings to make sure they are secure and leaks are not present. The component should be replaced immediately if there is any evidence of degradation that could result in failure.
Never attempt to repair a plastic fuel line/tube. Replace as necessary.
Avoid contact of any fuel tubes/hoses with other vehicle components that could cause abrasions or scuffing. Be sure that the plastic fuel lines/tubes are properly routed to prevent pinching and to avoid heat sources.
The lines/tubes/hoses used on fuel injected vehicles are of a special construction. This is due to the higher fuel pressures and the possibility of contaminated fuel in this system. If it is necessary to replace these lines/tubes/hoses, only those marked EFM/EFI may be used.
The hose clamps used to secure rubber hoses on fuel injected vehicles are of a special rolled edge construction. This construction is used to prevent the edge of the clamp from cutting into the hose. Only these rolled edge type clamps may be used in this system. All other types of clamps may cut into the hoses and cause high pressure fuel leaks.
Use new original equipment type hose clamps.
Tighten hose clamps to 1 N z m (15 in. lbs.) torque.
QUICK-CONNECT FITTINGS
Also refer to the previous Fuel Tubes/Lines/Hoses and Clamps section.
Different types of quick-connect fittings are used to attach various fuel system components. These are: a single-tab type, a two-tab type or a plastic retainer ring type.
SINGLE-TAB TYPE
This type of fitting is equipped with a single pull tab (Fig. 15). The tab is removable. After the tab is removed, the quick-connect fitting can be separated from the fuel system component.
Fig. 15 Single-Tab Type Fitting
CAUTION: The interior components (O-rings, spacers) of this type of quick-connect fitting are not serviced separately, but new pull tabs are available. Do not attempt to repair damaged fittings or fuel lines/ tubes. If repair is necessary, replace the complete fuel tube/quick-connect fitting assembly.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
DISCONNECTION/CONNECTION
(1) Disconnect negative battery cable from battery.
(2) Perform the fuel pressure release procedure.
Refer to the Fuel Pressure Release Procedure in this section.
(3) Clean the fitting of any foreign material before disassembly.
(4) Press the release tab on the side of fitting to release pull tab (Fig. 15).
14 - 10 FUEL SYSTEM
J
CAUTION: If this release tab is not pressed prior to releasing the pull tab, the pull tab will be damaged.
(5) While pressing the release tab on the side of the fitting, use a screwdriver to pry up the pull tab
(Fig. 16).
(12) Verify a locked condition by firmly pulling on fuel tube and fitting (15-30 lbs.).
(13) Connect negative cable to battery.
(14) Start engine and check for leaks.
TWO-TAB TYPE FITTING
This type of fitting is equipped with tabs located on both sides of the fitting (Fig. 18). These tabs are supplied for disconnecting the quick-connect fitting from component being serviced.
Fig. 16 Disconnecting Single-Tab Type Fitting
(6) Raise the pull tab until it separates from the quick-connect fitting (Fig. 17). Discard the old pull tab.
Fig. 18 Typical Two-Tab Type Quick-Connect Fitting
CAUTION: The interior components (O-rings, spacers) of this type of quick-connect fitting are not serviced separately, but new plastic retainers are available. Do not attempt to repair damaged fittings or fuel lines/tubes. If repair is necessary, replace the complete fuel tube/quick-connect fitting assembly.
Fig. 17 Removing Pull Tab
(7) Disconnect the quick-connect fitting from the fuel system component being serviced.
(8) Inspect the quick-connect fitting body and fuel system component for damage. Replace as necessary.
(9) Prior to connecting the quick-connect fitting to component being serviced, check condition of fitting and component. Clean the parts with a lint-free cloth. Lubricate them with clean engine oil.
(10) Insert the quick-connect fitting into the fuel tube or fuel system component until the built-on stop on the fuel tube or component rests against back of fitting.
(11) Obtain a new pull tab. Push the new tab down until it locks into place in the quick-connect fitting.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
DISCONNECTION/CONNECTION
(1) Disconnect negative battery cable from the battery.
(2) Perform the fuel pressure release procedure.
Refer to the Fuel Pressure Release Procedure in this section.
(3) Clean the fitting of any foreign material before disassembly.
(4) To disconnect the quick-connect fitting, squeeze the plastic retainer tabs against the sides of the quick-connect fitting with your fingers. Tool use is not required for removal and may damage plastic re-
J
FUEL SYSTEM 14 - 11
tainer. Pull the fitting from the fuel system component being serviced. The plastic retainer will remain on the component being serviced after fitting is disconnected. The O-rings and spacer will remain in the quick-connect fitting connector body.
(5) Inspect the quick-connect fitting body and component for damage. Replace as necessary.
CAUTION: When the quick-connect fitting was disconnected, the plastic retainer will remain on the component being serviced. If this retainer must be removed, very carefully release the retainer from the component with two small screwdrivers. After removal, inspect the retainer for cracks or any damage.
(6) Prior to connecting the quick-connect fitting to component being serviced, check condition of fitting and component. Clean the parts with a lint-free cloth. Lubricate them with clean engine oil.
(7) Insert the quick-connect fitting to the component being serviced and into the plastic retainer.
When a connection is made, a click will be heard.
(8) Verify a locked condition by firmly pulling on fuel tube and fitting (15-30 lbs.).
(9) Connect negative cable to battery.
(10) Start engine and check for leaks.
PLASTIC RETAINER RING TYPE FITTING
This type of fitting can be identified by the use of a full-round plastic retainer ring (Fig. 19) usually black in color.
CAUTION: The interior components (O-rings, spacers, retainers) of this type of quick-connect fitting are not serviced separately. Do not attempt to repair damaged fittings or fuel lines/tubes. If repair is necessary, replace the complete fuel tube/quickconnect fitting assembly.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
DISCONNECTION/CONNECTION
(1) Disconnect negative battery cable from the battery.
(2) Perform the fuel pressure release procedure.
Fig. 19 Plastic Retainer Ring Type Fitting
Refer to the Fuel Pressure Release Procedure in this section.
(3) Clean the fitting of any foreign material before disassembly.
(4) To release the fuel system component from the quick-connect fitting, firmly push the fitting towards the component being serviced while firmly pushing the plastic retainer ring into the fitting (Fig. 19).
With the plastic ring depressed, pull the fitting from the component. The plastic retainer ring must be pressed squarely into the fitting body. If this retainer is cocked during removal, it may be difficult to disconnect fitting. Use an open-end wrench on the shoulder of the plastic retainer ring to aid in disconnection.
After disconnection, the plastic retainer ring will remain with the quick-connect fitting connector body.
(5) Inspect fitting connector body, plastic retainer ring and fuel system component for damage. Replace as necessary.
(6) Prior to connecting the quick-connect fitting to component being serviced, check condition of fitting and component. Clean the parts with a lint-free cloth. Lubricate them with clean engine oil.
(7) Insert the quick-connect fitting into the component being serviced until a click is felt.
(8) Verify a locked condition by firmly pulling on fuel tube and fitting (15-30 lbs.).
(9) Connect negative battery cable to battery.
(10) Start engine and check for leaks.
14 - 12 FUEL SYSTEM
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FUEL TANKS
INDEX
page
Fuel Gauge Sending Unit
. . . . . . . . . . . . . . . . . . 15
Fuel Tank
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Fuel Tank Filler Tube Cap
. . . . . . . . . . . . . . . . . 12
Fuel Tank Pressure Relief/Rollover Valve
page
General Information
. . . . . . . . . . . . . . . . . . . . . . . 12
Heat Shields
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
No-Lead Fuel Tank Filler Tube
. . . . . . . . . . . . . . 12
GENERAL INFORMATION
All vehicles pass a full 360 degree rollover test without fuel leakage. To accomplish this, fuel and vapor flow controls are required for all fuel tank connections.
All models are equipped with a pressure relief/rollover valve mounted in the top of the fuel pump module. The return line from the fuel pump to the fuel tank contains a one-way check valve.
An evaporative control system prevents raw fuel vapor from escaping into the atmosphere. Fuel vapors from the fuel tank are collected in the EVAP canister. When the engine is operating, the vapors are drawn into the intake manifold to be used in combustion. Refer to Group 25, Emission Control
System for more information.
Inspect all hose/tube connections for completeness.
Be sure that leaks are not present. Replace any hose that is cracked, scuffed, swelled, has rubbed against other vehicle components or shows any other sign of wear that could lead to failure. If it is necessary to replace a hose, only hose marked EFM/EFI may be used.
When installing hoses, be sure that they are routed away from contact with other vehicle components.
The hose clamps used on fuel injected vehicles are of a special rolled edge construction to prevent the edge of the clamp from cutting into the hose. Only these rolled edge type clamps may be used on this system. Other types of clamps may cut into the hoses and cause high pressure fuel leaks.
FUEL TANK CAPACITIES
NO-LEAD FUEL TANK FILLER TUBE
All vehicles are designed to operate using Unleaded fuels. The diameter of the opening in the fuel tank filler neck is sized to only accept unleaded fuel nozzles. Gasoline station pumps for unleaded and leaded fuels have different size nozzles. Leaded fuel nozzles are larger in diameter than unleaded nozzles.
The fuel tank filler neck opening is also equipped with a deflector, which the smaller unleaded nozzle pushes back upon entering the filler neck. The deflector will prevent the larger diameter leaded fuel nozzles from entering the filler neck and will deflect fuel away from the filler neck. This happens if filling of the tank with leaded fuel is attempted.
A label is attached to the instrument panel under the fuel gauge that reads UNLEADED FUEL ONLY as a reminder to the driver. A similar label is located near the fuel tank filler.
FUEL TANK FILLER TUBE CAP
The loss of any fuel or vapor out of the filler neck is prevented by the use of a safety filler cap. This will release only under pressure of 10.9 to 13.45 kPa
(1.58 to 1.95 psi). The vacuum release is between .97
and 2.0 kPa (.14 and .29 psi). This cap must be replaced by a similar unit if replacement is necessary.
CAUTION: Remove the fuel tank filler tube cap prior to removing or repairing fuel lines to relieve fuel tank pressure.
HEAT SHIELDS
The sheet metal heat shields may have to be removed when servicing the fuel tank, fuel lines or vapor vent line. The heat shields must be installed to protect the lines and tank from the heat of the exhaust system. Refer to Group 11, Exhaust System and Intake Manifold for proper installation.
FUEL TANK
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39
PSI). THIS PRESSURE MUST BE RELEASED BE-
FORE SERVICING FUEL TANK.
J
REMOVAL—XJ MODELS
Perform the preceding Fuel System Pressure Release Procedure.
(1) Disconnect negative battery cable.
(2) Remove the fuel filler cap. Using an approved portable gasoline siphon/storage tank, drain fuel tank.
(3) Raise and support vehicle.
(4) Disconnect fuel fill hose and fill vent hose from filler neck (Fig. 1).
FUEL SYSTEM 14 - 13
Fig. 2 Skid Plate—XJ Models
Fig. 1 Filler Neck Hoses—XJ Models
(5) Disconnect fuel pump module wire connector.
Remove tie straps securing connector harness to fuel supply and return tubes.
WARNING: WRAP SHOP TOWELS AROUND FUEL
HOSES TO ABSORB ANY FUEL SPILLAGE DURING
FUEL TANK REMOVAL.
(6) Disconnect fuel tank vent hose from vent tube.
(7) Disconnect fuel supply and return hoses from tubes.
(8) If equipped, remove skid plate (Fig. 2).
(9) Remove fuel tank shield (Fig. 3).
(10) Center a transmission jack under the fuel tank.
(11) Remove support strap nuts. Move straps away from tank (Fig. 3).
(12) Lower fuel tank on transmission jack.
INSTALLATION—XJ MODELS
(1) Raise fuel tank into position. Connect fuel fill hose and vent hose to filler neck and tighten clamps.
(2) Wrap support straps around tank and over studs.
Tighten strap nuts to 11.3 N z m (100 in. lbs.) torque.
(3) Remove transmission jack.
Fig. 3 Fuel Tank Remove/Install—XJ Models
(4) Install tank shield.
(5) If equipped, install tank skid plate.
(6) Connect vent hose to vent tube.
(7) Connect fuel supply hose to supply tube and fuel return hose to return tube. Tighten hose clamps.
(8) Connect fuel pump module wire connector to harness connector. Secure fuel pump module wire harness to fuel tubes with tie straps.
(9) Lower vehicle.
(10) Fill fuel tank. Install filler cap.
(11) Connect negative battery cable to battery.
(12) Start vehicle and inspect for leaks.
14 - 14 FUEL SYSTEM
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REMOVAL—YJ MODELS
WARNING: EXTINGUISH ALL TOBACCO SMOKING
PRODUCTS BEFORE SERVICING THE FUEL SYS-
TEM. KEEP OPEN FLAME AWAY FROM FUEL SYS-
TEM COMPONENTS.
(1) Disconnect negative battery cable.
(2) Remove the fuel filler cap. Using an approved portable gasoline siphon/storage tank, drain fuel tank.
(3) Raise and support vehicle.
(4) Using a small straight blade screwdriver, pull back the stems of the push clips that secure the fuel filler neck shroud (located at bottom of left rear wheel well) in place (Fig. 4). This unlocks the push clip allowing them to be removed by pulling assembly out of shroud. Remove shroud.
(6) Disconnect fuel tank vent hose from vent tube.
Disconnect fuel supply and return hoses from tubes
(Fig. 6).
Fig. 6 Fuel Tank Hoses—YJ Models
The fuel tank and skid plate are removed as an assembly.
(7) Centrally position a transmission jack under skid plate/fuel tank assembly.
(8) Remove skid plate/fuel tank assembly mounting nuts (Fig. 7). Do not loosen tank strap nuts.
Fig. 4 Fuel Filler Neck Shroud—YJ Models
(5) Disconnect fuel fill hose and fill vent hose from filler neck (Fig. 5).
Fig. 5 Filler Neck Hoses—YJ Models
WARNING: WRAP SHOP TOWELS AROUND FUEL
HOSES TO ABSORB ANY FUEL SPILLAGE DURING
FUEL TANK REMOVAL.
Fig. 7 Fuel Tank—Remove/Install—YJ Models
(9) Lower the skid plate/fuel tank assembly slightly and disconnect the gauge sender wire connector.
(10) Lower the fuel tank on transmission jack.
(11) Remove tank strap nuts to remove tank from skid plate.
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FUEL SYSTEM 14 - 15
INSTALLATION—YJ MODELS
(1) Place tank into skid plate. Wrap straps around tank with strap bolts inserted through holes in skid plate. Tighten strap nuts to 7.3 N z m (65 in. lbs.) torque.
(2) Raise skid plate/fuel tank until gauge sender wire connector can be connected to harness connector.
(3) Finish raising skid plate/fuel tank assembly into position. Tighten mounting nuts to 16 N z m (12 ft. lbs.) torque. Remove transmission jack.
(4) Connect fuel fill hose and fill vent hose to filler neck. Tighten hose clamps.
(5) Connect vent hose to vent tube.
(6) Connect fuel supply hose to the supply tube and fuel return hose to return tube. Tighten hose clamps.
(7) Install fuel filler neck shroud with push clips.
(8) Lower vehicle.
(9) Fill fuel tank. Install filler cap.
(10) Connect negative battery cable to battery.
(11) Start vehicle and inspect for leaks.
FUEL GAUGE SENDING UNIT
The fuel gauge sending unit is attached to the fuel pump module. Refer to Fuel Pump Module in the
Fuel Delivery System section of this group.
FUEL TANK PRESSURE RELIEF/ROLLOVER VALVE
The fuel tank is equipped with a pressure relief/ rollover valve (Fig. 8). The dual function valve will relieve fuel tank pressure and prevent fuel flow through the fuel tank vent tubes in the event of accidental vehicle rollover.
controlled conditions). The plunger seats in the guide plate at the orifice preventing liquid fuel from reaching the EVAP canister. This is done if bottom of plunger is contacted by fuel sloshing in tank when vehicle is cornering.
In the event of accidental vehicle rollover, the valve is inverted. In this position the plunger is forced against the guide plate and raw fuel is prevented from flowing through the valve orifice into the fuel tank vent tube.
Fig. 8 Valve Location—Typical
The valve consists of a plunger, spring and orifice/ guide plate (Fig. 9). The valve is normally open allowing fuel vapor to vent to the EVAP canister. Here it is stored until it can be consumed by the engine (under
Fig. 9 Pressure Relief/Rollover Valve Operation
REMOVAL
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING THE PRESSURE RELIEF/
ROLLOVER VALVE, THE FUEL SYSTEM PRESSURE
MUST BE RELEASED. REFER TO THE FUEL PRES-
SURE RELEASE PROCEDURE IN THIS GROUP.
(1) Disconnect negative battery cable.
(2) Remove the fuel filler cap and drain fuel tank.
Refer to Fuel Tank Removal.
(3) Remove fuel tank. Refer to Fuel Tank Removal.
(4) The rollover valve is seated in a grommet. Remove by prying one side upward and then roll the grommet out of tank (Fig. 8).
INSTALLATION
(1) Start one side of grommet into opening in fuel tank. Using finger pressure only, press valve/grommet into place.
(2) Install fuel tank. Refer to Fuel Tank Installation.
(3) Fill fuel tank. Install fuel tank filler cap.
(4) Connect negative battery cable.
(5) Start vehicle and check for leaks.
14 - 16 FUEL SYSTEM
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ACCELERATOR PEDAL AND THROTTLE CABLE
GENERAL INFORMATION
The accelerator pedal is connected to the throttle body linkage by the throttle cable. The cable is protected by a plastic sheathing and is connected to the throttle body linkage by a ball socket. It is connected to the upper part of the accelerator pedal arm by a plastic retainer (clip)
(Fig. 10). This retainer (clip) snaps into the top of the accelerator pedal arm. Retainer tabs (built into the cable sheathing) (Fig. 10) fasten the cable to the dash panel.
Dual throttle return springs (attached to the throttle shaft) are used to close the throttle.
CAUTION: Never attempt to remove or alter these springs.
ACCELERATOR PEDAL
CAUTION: Be careful not to damage or kink the cable core wire (within the cable sheathing) while servicing the accelerator pedal or throttle cable.
REMOVAL
(1) From inside the vehicle, hold up accelerator pedal.
Remove plastic cable retainer (clip) and throttle cable core wire from upper end of accelerator pedal arm (Fig.
10). Plastic cable retainer (clip) snaps into pedal arm.
(2) Remove accelerator pedal mounting bracket nuts. Remove accelerator pedal assembly.
INSTALLATION
(1) Place accelerator pedal assembly over studs protruding from floor pan. Tighten mounting nuts to
5 N z m (36 in. lbs.) torque.
(2) Slide throttle cable into opening in top of pedal arm. Push plastic cable retainer (clip) into accelerator pedal arm opening until it snaps into place.
(3) Before starting engine, operate accelerator pedal to check for any binding.
THROTTLE CABLE
REMOVAL
(1) From inside the vehicle, hold up accelerator pedal.
Remove plastic cable retainer (clip) and throttle cable core wire from upper end of accelerator pedal arm (Fig.
10). Plastic cable retainer (clip) snaps into pedal arm.
(2) Remove the cable core wire at pedal arm.
(3) From inside the vehicle, pinch both sides of the cable housing retainer tabs (Fig. 10) at the dash panel. Remove cable housing from dash panel and pull into the engine compartment.
(4) Remove cable from clip on the engine cylinder head (valve) cover.
(5) Remove the throttle cable ball end socket at throttle body linkage (snaps off) (Fig. 11).
(6) Remove throttle cable from throttle body mounting bracket by compressing retainer tabs and pushing cable through hole in bracket. Remove throttle cable from vehicle.
INSTALLATION
(1) Slide throttle cable through hole in throttle body bracket until retainer tabs lock into bracket. Connect cable ball end to throttle body linkage ball (snaps on).
(2) Snap cable into clip on the engine cylinder head (valve) cover.
(3) Push other end of cable through opening in dash panel until retaining tabs lock into panel.
(4) From inside drivers compartment, slide throttle cable core wire into opening in top of accelerator pedal arm. Push cable retainer (clip) into pedal arm opening until it snaps in place.
(5) Before starting engine, operate accelerator pedal to check for any binding.
Fig. 10 Accelerator Pedal Mounting—Typical Fig. 11 Throttle (Accelerator) Cable—Typical
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FUEL SYSTEM 14 - 17
MULTI-PORT FUEL INJECTION (MFI)—COMPONENT DESCRIPTION/SYSTEM
OPERATION
INDEX
page
Air Conditioning (A/C) Clutch Relay—PCM Output
Air Conditioning (A/C) Controls—PCM Input
Auto Shut Down (ASD) Relay—PCM Output
Automatic Shut Down (ASD) Sense—PCM Input
Battery Voltage—PCM Input
. . . . . . . . . . . . . . . . 19
Brake Switch—PCM Input
. . . . . . . . . . . . . . . . . . 20
Camshaft Position Sensor—PCM Input
Crankshaft Position Sensor—PCM Input
Data Link Connector—PCM Input
Data Link Connector—PCM Output
EMR Lamp—PCM Output
. . . . . . . . . . . . . . . . . . 24
Engine Coolant Temperature Sensor—PCM Input . 21
Extended Idle Switch—PCM Input
Fuel Injectors—PCM Output
. . . . . . . . . . . . . . . . 25
Fuel Pressure Regulator
. . . . . . . . . . . . . . . . . . . 30
Fuel Pump Relay—PCM Output
Fuel Rail
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
General Information
. . . . . . . . . . . . . . . . . . . . . . . 17
Generator Field—PCM Output
. . . . . . . . . . . . . . . 25
Generator Lamp—PCM Output
. . . . . . . . . . . . . . 25
Idle Air Control (IAC) Motor—PCM Output
Ignition Circuit Sense—PCM Input
Ignition Coil—PCM Output
. . . . . . . . . . . . . . . . . . 26
page
Intake Air Temperature Sensor—PCM Input
Malfunction Indicator Lamp—PCM Output
Manifold Absolute Pressure (MAP) Sensor—
PCM Input
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Open Loop/Closed Loop Modes of Operation
Overdrive/Override Switch
. . . . . . . . . . . . . . . . . . 22
Oxygen (O2S) Sensor—PCM Input
Park/Neutral Switch—PCM Input
Power Ground
. . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Power Steering Pressure Switch—PCM Input
Powertrain Control Module (PCM)
Radiator Fan Relay—PCM Output
SCI Receive—PCM Input
. . . . . . . . . . . . . . . . . . 22
SCI Transmit—PCM Output
. . . . . . . . . . . . . . . . . 26
Sensor Return—PCM Input
. . . . . . . . . . . . . . . . . 23
Shift Indicator—PCM Output
. . . . . . . . . . . . . . . . 26
Speed Control—PCM Input
. . . . . . . . . . . . . . . . . 23
Speed Control—PCM Output
. . . . . . . . . . . . . . . . 27
Tachometer—PCM Output
. . . . . . . . . . . . . . . . . . 27
Throttle Body
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Throttle Position Sensor (TPS)—PCM Input
Torque Converter Clutch Relay—PCM Output
Vehicle Speed Sensor—PCM Input
GENERAL INFORMATION
All 2.5L 4 cylinder and 4.0L 6 cylinder engines are equipped with sequential Multi-Port Fuel Injection
(MFI). The MFI system provides precise air/fuel ratios for all driving conditions.
The Powertrain Control Module (PCM) operates the fuel system. The PCM was formerly referred to as the SBEC or engine controller. The PCM is a preprogrammed, dual microprocessor digital computer.
It regulates ignition timing, air-fuel ratio, emission control devices, charging system, speed control, air conditioning compressor clutch engagement and idle speed. The PCM can adapt its programming to meet changing operating conditions.
Powertrain Control Module (PCM) Inputs represent the instantaneous engine operating conditions.
Air-fuel mixture and ignition timing calibrations for various driving and atmospheric conditions are preprogrammed into the PCM. The PCM monitors and analyzes various inputs. It then computes engine fuel and ignition timing requirements based on these inputs. Fuel delivery control and ignition timing will then be adjusted accordingly.
Other inputs to the PCM are provided by the brake light switch, air conditioning select switch and the speed control switches. All inputs to the PCM are converted into signals.
Electrically operated fuel injectors spray fuel in precise metered amounts into the intake port directly above the intake valve. The injectors are fired in a specific sequence by the PCM. The PCM maintains an air/fuel ratio of 14.7 to 1 by constantly adjusting injector pulse width. Injector pulse width is the length of time that the injector opens and sprays fuel into the chamber. The PCM adjusts injector pulse width by opening and closing the ground path to the injector.
Manifold absolute pressure (air density) and engine rpm (speed) are the primary inputs that determine fuel injector pulse width. The PCM also monitors other inputs when adjusting air-fuel ratio.
Inputs That Effect Fuel Injector Pulse Width
• Exhaust gas oxygen content
•
Engine coolant temperature
• Manifold absolute pressure (MAP)
• Engine speed
• Throttle position
• Battery voltage
• Air conditioning selection
• Transmission gear selection (automatic transmissions only)
• Speed control
The powertrain control module (PCM) adjusts ignition timing by controlling ignition coil operation. The ignition coil receives battery voltage when the ignition key is in the run or starter position. The PCM provides a ground for the ignition coil. The coil dis-
14 - 18 FUEL SYSTEM
J charges when the PCM supplies a ground. By switching the ground path on and off, the PCM regulates ignition timing.
The sensors and switches that provide inputs to the powertrain control module (PCM) comprise the Engine Control System. It is also comprised of the PCM
Outputs (engine control devices that the are operated by the PCM).
SYSTEM DIAGNOSIS
The powertrain control module (PCM) tests many of its own input and output circuits. If a Diagnostic
Trouble Code (DTC) is found in a major system, this information is stored in the PCM memory. Refer to
On-Board Diagnostics in the MFI System—General
Diagnosis section of this group for DTC information.
POWERTRAIN CONTROL MODULE (PCM)
The PCM operates the fuel system. The PCM was formerly referred to as the SBEC or engine controller. The PCM is a pre-programmed, dual microprocessor digital computer. It regulates ignition timing, air-fuel ratio, emission control devices, charging system, speed control, air conditioning compressor clutch engagement and idle speed. The PCM can adapt its programming to meet changing operating conditions.
On XJ models, the PCM is located in the engine compartment next to the air cleaner (Fig. 1). On YJ models, the PCM is located in the engine compartment behind the windshield washer fluid reservoir
(Fig. 2).
Fig. 1 PCM Location—XJ Models
The PCM receives input signals from various switches and sensors. Based on these inputs, the
PCM regulates various engine and vehicle operations through different system components. These components are referred to as PCM Outputs. The sensors and switches that provide inputs to the PCM are considered PCM Inputs.
Fig. 2 PCM Location—YJ Models
The PCM adjusts ignition timing based upon inputs it receives from sensors that react to: engine rpm, manifold absolute pressure, coolant temperature, throttle position, transmission gear selection
(automatic transmission), vehicle speed and the brake switch.
The PCM adjusts idle speed based on inputs it receives from sensors that react to: throttle position, vehicle speed, transmission gear selection, coolant temperature and from inputs it receives from the air conditioning clutch switch and brake switch.
Based on inputs that it receives, the PCM adjusts ignition coil dwell. The PCM also adjusts the generator charge rate through control of the generator field and provides speed control operation.
Powertrain Control Module (PCM) Inputs:
•
Generator output
• A/C request (if equipped with factory A/C)
• A/C select (if equipped with factory A/C)
• Auto shut down (ASD) sense
• Intake air temperature sensor
• Battery voltage
• Brake switch
• Engine coolant temperature sensor
• Crankshaft position sensor
• Ignition circuit sense (ignition switch in run position)
• Manifold absolute pressure sensor
• Overdrive/override switch
• Oxygen sensor
• Park/neutral switch (auto. trans. only)
• SCI receive (DRB scan tool connection)
• Speed control resume switch
• Speed control set switch
• Speed control on/off switch
• Camshaft position sensor signal
• Throttle position sensor
• Vehicle speed sensor
•
Sensor return
•
Power ground
J
• Signal ground
Powertrain Control Module (PCM) Outputs
• A/C clutch relay
• Idle air control (IAC) motor
• Auto shut down (ASD) relay
• Generator field
•
Malfunction indicator lamp
• Fuel injectors
• Fuel pump relay
•
Ignition coil
• SCI transmit (DRB scan tool connection)
• Shift indicator lamp (manual transmission only)
• Speed control vacuum solenoid
•
Speed control vent solenoid
• Tachometer (on instrument panel, if equipped)
• Torque converter clutch relay (3-speed auto. trans.
only)
The PCM contains a voltage convertor. This converts battery voltage to a regulated 8.0 volts. It is used to power the crankshaft position sensor and camshaft position sensor. The PCM also provides a five (5) volt supply for the Manifold Absolute Pressure (MAP) sensor and Throttle Position Sensor
(TPS).
AIR CONDITIONING (A/C) CONTROLS—PCM INPUT
The A/C control system information applies to factory installed air conditioning units only.
A/C SELECT SIGNAL: When the A/C switch is in the ON position and the A/C low pressure switch is closed, an input signal is sent to the powertrain control module (PCM). The signal informs the PCM that the A/C has been selected. The PCM adjusts idle speed to a pre-programmed rpm through the idle air control (IAC) motor to compensate for increased engine load.
A/C REQUEST SIGNAL: Once A/C has been selected, the PCM receives the A/C request signal from the evaporator switch. The input indicates that the evaporator temperature is in the proper range for
A/C application. The PCM uses this input to cycle the A/C compressor clutch (through the A/C relay). It will also determine the correct engine idle speed through the IAC motor position.
If the A/C low pressure switch opens (indicating a low refrigerant level), the PCM will not receive an
A/C select signal. The PCM will then remove the ground from the A/C relay. This will deactivate the
A/C compressor clutch.
If the evaporator switch opens, (indicating that evaporator is not in proper temperature range), the
PCM will not receive the A/C request signal. The
PCM will then remove the ground from the A/C relay, deactivating the A/C compressor clutch.
FUEL SYSTEM 14 - 19
AUTOMATIC SHUT DOWN (ASD) SENSE—PCM
INPUT
A 12 volt signal at this input indicates to the PCM that the ASD has been activated. The ASD relay is located in the power distribution center (PDC) in the engine compartment (Figs. 3 or 4). It is used to connect oxygen sensor heater element, ignition coil, generator field winding and fuel injectors to 12 volt + power supply. Also refer to Automatic Shut Down
Relay—PCM Output.
Fig. 3 Power Distribution Center—YJ Models
Fig. 4 Power Distribution Center—XJ Models
This input is used only to sense that the ASD relay is energized. If the PCM does not see 12 volts at this input when the ASD should be activated, it will set a
Diagnostic Trouble Code (DTC).
BATTERY VOLTAGE—PCM INPUT
The battery voltage input provides power to the powertrain control module (PCM). It also informs the
PCM what voltage level is supplied to the ignition coil and fuel injectors.
If battery voltage is low, the PCM will increase injector pulse width (period of time that the injector is
14 - 20 FUEL SYSTEM
energized). This is done to compensate for the reduced flow through injector caused by the lowered voltage.
BRAKE SWITCH—PCM INPUT
When the brake light switch is activated, the powertrain control module (PCM) receives an input indicating that the brakes are being applied. After receiving this input, the PCM maintains idle speed to a scheduled rpm through control of the idle air control (IAC) motor. The brake switch input is also used to operate the speed control system.
CAMSHAFT POSITION SENSOR—PCM INPUT
A sync signal is provided by the camshaft position sensor located in the ignition distributor (Fig. 5). The sync signal from this sensor works in conjunction with the crankshaft position sensor to provide the powertrain control module (PCM) with inputs. This is done to establish and maintain correct injector firing order.
Refer to Camshaft Position Sensor in Group 8D, Ignition System for more information.
Fig. 6 Data Link Connector—YJ Models—Typical
J
Fig. 5 Camshaft Position Sensor
DATA LINK CONNECTOR—PCM INPUT
The data link connector (diagnostic scan tool connector) links the DRB scan tool with the powertrain control module (PCM). The data link connector is located in the engine compartment (Figs. 6 or 7). For operation of the DRB scan tool, refer to the appropriate Powertrain Diagnostic Procedures service manual.
The data link connector uses two different pins on the PCM. One is for Data Link Transmit and the other is for Data Link Receive.
Fig. 7 Data Link Connector—XJ Models—Typical
INTAKE AIR TEMPERATURE SENSOR—PCM INPUT
The intake manifold air temperature sensor is installed in the intake manifold with the sensor element extending into the air stream (Figs. 8 or 9).
The sensor provides an input voltage to the powertrain control module (PCM) indicating intake manifold air temperature. The input is used along with inputs from other sensors to determine injector pulse width. As the temperature of the air-fuel stream in the manifold varies, the sensor resistance changes.
This results in a different input voltage to the PCM.
CRANKSHAFT POSITION SENSOR—PCM INPUT
This sensor is a Hall Effect device that detects notches in the flywheel (manual transmission), or flexplate (automatic transmission).
This sensor is used to indicate to the powertrain control module (PCM) that a spark and or fuel injection event is to be required. The output from this sensor, in conjunction with the camshaft position sensor signal, is used to differentiate between fuel injection and spark events. It is also used to synchronize the fuel injectors with their respective cylinders.
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FUEL SYSTEM 14 - 21
Fig. 8 Sensor Location—4.0L Engine
Fig. 9 Sensor Location—2.5L Engine
Refer to Group 8D, Ignition System for more crankshaft position sensor information.
The engine will not operate if the PCM does not receive a crankshaft position sensor input.
ENGINE COOLANT TEMPERATURE SENSOR—PCM
INPUT
The coolant temperature sensor is installed in the thermostat housing (Fig. 10) and protrudes into the water jacket. The sensor provides an input voltage to the powertrain control module (PCM) relating coolant temperature. The PCM uses this input along with inputs from other sensors to determine injector pulse width and ignition timing. As coolant temperature varies, the coolant temperature sensor’s resistance changes. The change in resistance results in a different input voltage to the PCM.
When the engine is cold, the PCM will operate in
Open Loop cycle. It will demand slightly richer airfuel mixtures and higher idle speeds. This is done until normal operating temperatures are reached.
Refer to Open Loop/Closed Loop Modes of Operation in this section of the group for more information.
Fig. 10 Coolant Temperature Sensor—Typical
EXTENDED IDLE SWITCH—PCM INPUT
OPTIONAL POLICE PACKAGE ONLY
The extended idle switch is used to raise the engine idle speed to approximately 1000 rpm. This is when the shifter is in either the Park or Neutral position. A rocker-type 2-wire switch (extended idle switch) is mounted to the instrument panel. This switch will supply a ground circuit to the powertrain control module (PCM). The switch is available only with 4.0L engine when supplied with the optional police package.
For testing and diagnosis of this switch and its circuit, refer to the MFI System—General Diagnosis section of this group.
IGNITION CIRCUIT SENSE—PCM INPUT
The ignition circuit sense input tells the powertrain control module (PCM) the ignition switch has energized the ignition circuit. Refer to the wiring diagrams for circuit information.
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR—PCM INPUT
The MAP sensor reacts to absolute pressure in the intake manifold. It provides an input voltage to the powertrain control module (PCM). As engine load changes, manifold pressure varies. The change in manifold pressure causes MAP sensor voltage to change. The change in MAP sensor voltage results in a different input voltage to the PCM. The input voltage level supplies the PCM with information about ambient barometric pressure during engine start-up
(cranking) and engine load while the engine is running. The PCM uses this input along with inputs from other sensors to adjust air-fuel mixture.
The MAP sensor is mounted on the dash panel.
The sensor is connected to the throttle body with a vacuum hose and to the PCM electrically.
14 - 22 FUEL SYSTEM
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OVERDRIVE/OVERRIDE SWITCH
On vehicles equipped with overdrive, the powertrain control module (PCM) regulates the 3-4 overdrive up-shift and down-shift through the overdrive solenoid.
Refer to Group 21 for more information.
OXYGEN (O2S) SENSOR—PCM INPUT
The O2S sensor is located in the exhaust down pipe
(Fig. 11). It provides an input voltage to the powertrain control module (PCM) relating the oxygen content of the exhaust gas.
The PCM uses this information to fine tune the air-fuel ratio by adjusting injector pulse width.
The O2S sensor produces voltages from 0 to 1 volt.
This voltage will depend upon the oxygen content of the exhaust gas in the exhaust manifold. When a large amount of oxygen is present (caused by a lean air-fuel mixture), the sensor produces a low voltage.
When there is a lesser amount present (rich air-fuel mixture) it produces a higher voltage. By monitoring the oxygen content and converting it to electrical voltage, the sensor acts as a rich-lean switch.
The oxygen sensor is equipped with a heating element that keeps the sensor at proper operating temperature during all operating modes. Maintaining correct sensor temperature at all times allows the system to enter into closed loop operation sooner.
In Closed Loop operation, the powertrain control module (PCM) monitors the O2S sensor input (along with other inputs). It then adjusts the injector pulse width accordingly. During Open Loop operation, the
PCM ignores the O2S sensor input and adjusts injector pulse width to a preprogrammed value (based on other sensor inputs).
gear selection. This input is used to determine idle speed (varying with gear selection), fuel injector pulse width and ignition timing advance. Refer to
Group 21, Transmissions, for testing, replacement and adjustment information.
POWER GROUND
The power ground is used to control ground circuits for the following powertrain control module (PCM) loads:
•
Generator Field Winding
• 8 volt (PCM) power supply
• Fuel Injectors
• Ignition Coil
POWER STEERING PRESSURE SWITCH—PCM
INPUT
A pressure sensing switch is included in the power steering system (mounted on the high-pressure line).
This switch will be on vehicles equipped with a 2.5L
engine and power steering. The switch (Fig. 12 YJ
Models or Fig. 13 XJ Models) provides an input to the PCM. This input is provided during periods of high pump load and low engine rpm; such as during parking maneuvers. The PCM will then increase the idle speed through the idle air control (IAC) motor.
This is done to prevent the engine from stalling under the increased load.
When steering pump pressure exceeds 1896 kPa
6
172 kPa (275 6 25 psi) the PCM will increase the engine idle speed. This will prevent the engine from stalling.
Fig. 11 Heated Oxygen Sensor Location—Typical
PARK/NEUTRAL SWITCH—PCM INPUT
The park/neutral switch is located on the transmission housing and provides an input to the powertrain control module (PCM). This will indicate that the automatic transmission is in Park, Neutral or a drive
Fig. 12 Power Steering Pump Pressure Switch—YJ
Models
SCI RECEIVE—PCM INPUT
SCI Receive is the serial data communication receive circuit for the DRB scan tool. The powertrain control module (PCM) receives data from the DRB through the SCI Receive circuit.
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FUEL SYSTEM 14 - 23
rent engine operating conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing.
Fig. 13 Power Steering Pump Pressure Switch—XJ
Models
SPEED CONTROL—PCM INPUT
The speed control system provides three separate inputs to the powertrain control module (PCM); On/
Off, Set and Resume. The On/Off input informs the
PCM that the speed control system has been activated. The Set input informs the PCM that a fixed vehicle speed has been selected. The Resume input indicates to the PCM that the previous fixed speed is requested.
The speed control operating range is from 50 km/h to 142 km/h (35 to 85 mph). Inputs that effect speed control operation are:
•
Park/neutral switch
• Vehicle speed sensor
• Throttle position sensor
Refer to Group 8H for further speed control information.
SENSOR RETURN—PCM INPUT
Sensor Return provides a low noise ground reference for all system sensors.
THROTTLE POSITION SENSOR (TPS)—PCM INPUT
The Throttle Position Sensor (TPS) is mounted on the throttle body (Figs. 14 or 15). The TPS is a variable resistor that provides the powertrain control module (PCM) with an input signal (voltage) that represents throttle blade position. The sensor is connected to the throttle blade shaft. As the position of the throttle blade changes, the resistance of the TPS changes.
The PCM supplies approximately 5 volts to the
TPS. The TPS output voltage (input signal to the
PCM) represents the throttle blade position. The
PCM receives an input signal voltage from the TPS.
This will vary in an approximate range of from 1 volt at minimum throttle opening (idle), to 4 volts at wide open throttle. Along with inputs from other sensors, the PCM uses the TPS input to determine cur-
Fig. 14 Throttle Position Sensor—2.5L Engine
Fig. 15 Throttle Position Sensor—4.0L Engine
VEHICLE SPEED SENSOR—PCM INPUT
The vehicle speed sensor (Fig. 16) is located in the extension housing of the transmission (2 wheel drive) or on the transfer case extension housing (4 wheel drive). The sensor input is used by the powertrain control module (PCM) to determine vehicle speed and distance traveled.
The speed sensor generates 8 pulses per sensor revolution. These signals, in conjunction with a closed throttle signal from the throttle position sensor, indicate a closed throttle deceleration to the PCM. When the vehicle is stopped at idle, a closed throttle signal is received by the PCM (but a speed sensor signal is not received).
Under deceleration conditions, the PCM adjusts the idle air control (IAC) motor to maintain a desired
MAP value. Under idle conditions, the PCM adjusts the IAC motor to maintain a desired engine speed.
14 - 24 FUEL SYSTEM
J
Fig. 16 Vehicle Speed Sensor—Typical
AIR CONDITIONING (A/C) CLUTCH RELAY—PCM
OUTPUT
The powertrain control module (PCM) activates the
A/C compressor through the A/C clutch relay. The
PCM regulates A/C compressor operation by switching the ground circuit for the A/C clutch relay on and off. The relay is located in the Power Distribution Center (PDC) (Figs. 17 or 18). For the location of the relay within the PDC, refer to label on PDC cover.
Fig. 17 PDC—YJ Models
When the PCM receives a request for A/C from A/C evaporator switch, it will adjust idle air control (IAC) motor position. This is done to increase idle speed.
The PCM will then activate the A/C clutch through the A/C clutch relay. The PCM adjusts idle air control (IAC) stepper motor position to compensate for increased engine load from the A/C compressor.
By switching the ground path for the relay on and off, the PCM is able to cycle the A/C compressor clutch. This is based on changes in engine operating conditions. If, during A/C operation, the PCM senses low idle speeds or a wide open throttle condition, it
Fig. 18 PDC—XJ Models will de-energize the relay. This prevents A/C clutch engagement. The relay will remain de-energized until the idle speed increases or the wide open throttle condition exceeds 15 seconds or no longer exists. The
PCM will also de-energize the relay if coolant temperature exceeds 125°C (257°F).
AUTO SHUT DOWN (ASD) RELAY—PCM OUTPUT
The ASD relay is located in the Power Distribution
Center (PDC) (Figs. 17 or 18). For the location of this relay within the PDC, refer to label on PDC cover.
The ASD supplies battery voltage to the fuel pump, fuel injector, ignition coil, generator field winding and oxygen (O2S) sensor heating element. The ground circuit for the coil in the ASD relay is controlled by the powertrain control module (PCM). The
PCM operates the relay by switching the ground circuit on and off.
The fuel pump relay is controlled by the PCM through same circuit that the ASD relay is controlled.
The powertrain control module (PCM) energizes the fuel pump through the fuel pump relay. (The
PCM was formerly referred to as the SBEC or engine controller). Battery voltage is applied to the relay from the ignition switch. The relay is energized when a ground is provided by the PCM. The relay is located in the Power Distribution Center (PDC) (Figs.
17 or 18). For the location of fuel pump relay within
PDC, refer to label on PDC cover.
For the 1994 model year, the ballast resistor and ballast resistor bypass relay are no longer used to control the fuel pump circuit.
DATA LINK CONNECTOR—PCM OUTPUT
Refer to the previous paragraphs on Data Link
Connector—PCM Input for information.
EMR LAMP—PCM OUTPUT
The EMR lamp is not used for the 1994 model year.
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FUEL SYSTEM 14 - 25
FUEL PUMP RELAY—PCM OUTPUT
The PCM energizes the fuel pump through the fuel pump relay. Battery voltage is applied to the relay from the ignition switch. The relay is energized when a ground is provided by the PCM. Refer to Automatic
Shut Down Relay for additional information.
FUEL INJECTORS—PCM OUTPUT
Six individual fuel injectors are used with the 4.0L
6 cylinder engine. Four individual fuel injectors are used with the 2.5L 4 cylinder engine. The injectors are attached to the fuel rail (Fig. 19).
The nozzle ends of the injectors are positioned into openings in the intake manifold just above the intake valve ports of the cylinder head. The engine wiring harness connector for each fuel injector is equipped with an attached numerical tag (INJ 1, INJ
2 etc.). This is used to identify each fuel injector.
The injectors are energized individually in a sequential order by the powertrain control module
(PCM). The PCM will adjust injector pulse width by switching the ground path to each individual injector on and off. Injector pulse width is the period of time that the injector is energized. The PCM will adjust injector pulse width based on various inputs it receives.
During start up, battery voltage is supplied to the injectors through the ASD relay. When the engine is operating, voltage is supplied by the charging system. The PCM determines injector pulse width based on various inputs.
GENERATOR LAMP—PCM OUTPUT
IF EQUIPPED
If the powertrain control module (PCM) senses a low charging condition in the charging system, it will illuminate the generator lamp on the instrument panel. For example, during low idle with all accessories turned on, the light may momentarily go on.
Once the PCM corrects idle speed to a higher rpm, the light will go out. Refer to Group 8A, Battery/
Starting/Charging Systems for charging system information.
IDLE AIR CONTROL (IAC) MOTOR—PCM OUTPUT
The IAC motor is mounted on the throttle body
(Figs. 20 or 21) and is controlled by the powertrain control module (PCM).
Fig. 20 IAC Motor—4.0L Engine
Fig. 19 Fuel Injectors—Typical
GENERATOR FIELD—PCM OUTPUT
The powertrain control module (PCM) regulates the charging system voltage within a range of 12.9 to
15.0 volts. Refer to Group 8A for charging system information.
Fig. 21 IAC Motor—2.5L Engine
The throttle body has an air control passage that provides air for the engine at idle (the throttle plate is closed). The IAC motor pintle protrudes into the air control passage and regulates air flow through it.
Based on various sensor inputs, the powertrain control module (PCM) adjusts engine idle speed by mov-
14 - 26 FUEL SYSTEM
J ing the IAC motor pintle in and out of the air control passage. The IAC motor is positioned when the ignition key is turned to the On position.
A (factory adjusted) set screw is used to mechanically limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle
speed using this screw. All idle speed functions are controlled by the PCM.
IGNITION COIL—PCM OUTPUT
System voltage is supplied to the ignition coil positive terminal. The powertrain control module (PCM) operates the ignition coil. Base (initial) ignition
timing is not adjustable. The PCM adjusts ignition timing to meet changing engine operating conditions.
The ignition coil is located near the ignition distributor (Fig. 22).
Refer to Group 8D, Ignition System for additional information.
RADIATOR FAN RELAY—PCM OUTPUT
XJ MODELS ONLY
The electric radiator cooling fan used in XJ models
(equipped with 4.0L engine, heavy duty cooling and/or air conditioning) is controlled by the powertrain control module (PCM) through radiator fan relay. The relay is energized when coolant temperature is above 103°C (217°F). It will then de-energize when coolant temperature drops to 98°C (208°F). Refer to
Group 7, Cooling Systems for more information.
The relay is located in the power distribution center (PDC) (Fig. 23).
The electric radiator cooling fan is not used on YJ models.
Fig. 22 Ignition Coil—Typical
MALFUNCTION INDICATOR LAMP—PCM OUTPUT
The Malfunction Indicator Lamp (formerly referred to as the Check Engine Lamp) illuminates on the instrument panel each time the ignition key is turned on. It will stay on for three seconds as a bulb test.
If the powertrain control module (PCM) receives an incorrect signal, or no signal from certain sensors or emission related systems, the lamp is turned on. This is a warning that the PCM has recorded a system or sensor malfunction. In some cases, when a problem is declared, the PCM will go into a limp-in mode. This is an attempt to keep the system operating. It signals an immediate need for service.
The lamp can also be used to display a Diagnostic
Trouble Code (DTC). Cycle the ignition switch On-
Off-On-Off-On within three seconds and any codes stored in the PCM memory will be displayed. This is done in a series of flashes representing digits. Refer to On-Board Diagnostics in the General Diagnosis section of this group for more information.
Fig. 23 PDC—XJ Models
SCI TRANSMIT—PCM OUTPUT
SCI Transmit is the serial data communication transmit circuit for the DRB scan tool. The powertrain control module (PCM) transmits data to the
DRB through the SCI Transmit circuit.
SHIFT INDICATOR—PCM OUTPUT
Vehicles equipped with manual transmissions have an Up-Shift indicator lamp. The lamp is controlled by the powertrain control module (PCM). The lamp illuminates on the instrument panel to indicate when the driver should shift to the next highest gear for best fuel economy. The PCM will turn the lamp OFF after 3 to 5 seconds if the shift of gears is not performed. The up-shift light will remain off until vehicle stops accelerating and is brought back to range of up-shift light operation. This will also happen if vehicle is shifted into fifth gear.
The indicator lamp is normally illuminated when the ignition switch is turned on and it is turned off when the engine is started up. With the engine running, the lamp is turned on/off depending upon engine speed and load.
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FUEL SYSTEM 14 - 27
SPEED CONTROL—PCM OUTPUT
Speed control operation is regulated by the powertrain control module (PCM). The PCM controls the vacuum to the throttle actuator through the speed control vacuum and vent solenoids. Refer to Group
8H for speed control information.
TACHOMETER—PCM OUTPUT
The powertrain control module (PCM) supplies engine rpm values to the instrument cluster tachometer (if equipped). Refer to Group 8E for tachometer information.
TORQUE CONVERTER CLUTCH RELAY—PCM
OUTPUT
ALL 2.5L 4 CYL. WITH 3-SPEED AUTO. TRANS
4.0L 6 CYL. YJ MODELS WITH 3-SPEED AUTO.
TRANS
The transmission mounted torque converter clutch
(TCC) solenoid is used to control the torque converter. The solenoid is controlled through the powertrain control module (PCM) and by the TCC relay.
This relay is used only on vehicles equipped with a
3-speed automatic transmission.
An electrical output signal is sent from the PCM to the TCC relay after the PCM receives information from the vehicle speed, MAP, throttle position and engine coolant temperature sensors. After the TCC relay receives this necessary information, it will send a signal to the torque converter clutch solenoid to control the torque converter.
On YJ models the TCC relay is located in the engine compartment, on the cowl panel and near the battery (Fig. 24). On XJ models the TCC relay is located in the power distribution center (PDC) (Fig.
23).
Fig. 24 TCC Relay Location—YJ Models
OPEN LOOP/CLOSED LOOP MODES OF
OPERATION
As input signals to the powertrain control module
(PCM) change, the PCM adjusts its response to the output devices. For example, the PCM must calculate different injector pulse width and ignition timing for idle than it does for wide open throttle (WOT). There are several different modes of operation that determine how the PCM responds to the various input signals.
MODES
• Open Loop
• Closed Loop
During Open Loop modes, the powertrain control module (PCM) receives input signals and responds only according to preset PCM programming. Input from the oxygen (O2S) sensor is not monitored during Open Loop modes.
During Closed Loop modes, the PCM will monitor the oxygen (O2S) sensor input. This input indicates to the PCM whether or not the calculated injector pulse width results in the ideal air-fuel ratio. This ratio is 14.7 parts air-to-1 part fuel. By monitoring the exhaust oxygen content through the O2S sensor, the PCM can fine tune the injector pulse width. This is done to achieve optimum fuel economy combined with low emission engine performance.
The fuel injection system has the following modes of operation:
• Ignition switch ON
• Engine start-up (crank)
• Engine warm-up
• Idle
•
Cruise
•
Acceleration
•
Deceleration
•
Wide open throttle (WOT)
•
Ignition switch OFF
The ignition switch On, engine start-up (crank), engine warm-up, acceleration, deceleration and wide open throttle modes are Open Loop modes. The idle and cruise modes, (with the engine at operating temperature) are Closed Loop modes.
IGNITION SWITCH (KEY-ON) MODE
This is an Open Loop mode. When the fuel system is activated by the ignition switch, the following actions occur:
• The powertrain control module (PCM) pre-positions the idle air control (IAC) motor.
• The PCM determines atmospheric air pressure from the MAP sensor input to determine basic fuel strategy.
• The PCM monitors the engine coolant temperature sensor input. The PCM modifies fuel strategy based on this input.
14 - 28 FUEL SYSTEM
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• Intake manifold air temperature sensor input is monitored
• Throttle position sensor (TPS) is monitored
• The auto shut down (ASD) relay is energized by the PCM for approximately three seconds.
• The fuel pump is energized through the fuel pump relay by the PCM. The fuel pump will operate for approximately one second unless the engine is operating or the starter motor is engaged
• The O2S sensor heater element is energized through the fuel pump relay. The O2S sensor input is not used by the PCM to calibrate air-fuel ratio during this mode of operation.
•
The up-shift indicator light is illuminated (manual transmission only).
ENGINE START-UP MODE
This is an Open Loop mode. The following actions occur when the starter motor is engaged.
The powertrain control module (PCM) receives inputs from:
• Battery voltage
• Engine coolant temperature sensor
• Crankshaft position sensor
• Intake manifold air temperature sensor
• Manifold absolute pressure (MAP) sensor
• Throttle position sensor (TPS)
• Starter motor relay
• Camshaft position sensor signal
The PCM monitors the crankshaft position sensor.
If the PCM does not receive a crankshaft position sensor signal within 3 seconds of cranking the engine, it will shut down the fuel injection system.
The fuel pump is activated by the PCM through the fuel pump relay.
Voltage is applied to the fuel injectors with the
PCM. The PCM will then control the injection sequence and injector pulse width by turning the ground circuit to each individual injector on and off.
The PCM determines the proper ignition timing according to input received from the crankshaft position sensor.
ENGINE WARM-UP MODE
This is an Open Loop mode. During engine warmup, the powertrain control module (PCM) receives inputs from:
• Battery voltage
• Crankshaft position sensor
• Engine coolant temperature sensor
• Intake manifold air temperature sensor
• Manifold absolute pressure (MAP) sensor
• Throttle position sensor (TPS)
• Camshaft position sensor signal (in the distributor)
• Park/Neutral Switch (Gear indicator signal—auto.
trans. only)
• Air conditioning select signal (if equipped)
• Air conditioning request signal (if equipped)
Based on these inputs the following occurs:
• Voltage is applied to the fuel injectors with the powertrain control module (PCM). The PCM will then control the injection sequence and injector pulse width by turning the ground circuit to each individual injector on and off.
• The PCM adjusts engine idle speed through the idle air control (IAC) motor and adjusts ignition timing.
• The PCM operates the A/C compressor clutch through the clutch relay. This is done if A/C has been selected by the vehicle operator and requested by the A/C thermostat.
•
If the vehicle has a manual transmission, the upshift light is operated by the PCM.
• When engine has reached operating temperature, the PCM will begin monitoring O2S sensor input.
The system will then leave the warm-up mode and go into closed loop operation.
IDLE MODE
When the engine is at operating temperature, this is a Closed Loop mode. At idle speed, the powertrain control module (PCM) receives inputs from:
• Air conditioning select signal (if equipped)
• Air conditioning request signal (if equipped)
• Battery voltage
• Crankshaft position sensor
• Engine coolant temperature sensor
• Intake manifold air temperature sensor
• Manifold absolute pressure (MAP) sensor
• Throttle position sensor (TPS)
• Camshaft position sensor signal (in the distributor)
• Battery voltage
• Park/Neutral Switch (gear indicator signal—auto.
trans. only)
•
Oxygen sensor
Based on these inputs, the following occurs:
•
Voltage is applied to the fuel injectors with the powertrain control module (PCM). The PCM will then control injection sequence and injector pulse width by turning the ground circuit to each individual injector on and off.
• The PCM monitors the O2S sensor input and adjusts air-fuel ratio by varying injector pulse width. It also adjusts engine idle speed through the idle air control (IAC) motor.
• The PCM adjusts ignition timing by increasing and decreasing spark advance.
• The PCM operates the A/C compressor clutch through the clutch relay. This happens if A/C has been selected by the vehicle operator and requested by the A/C thermostat.
The optional Extended Idle Switch is used to raise the engine idle speed to approximately 1000 rpm.
This is when the shifter is in either the Park or Neutral position. A rocker-type 2-wire switch (extended idle switch) is mounted to the instrument panel. This
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FUEL SYSTEM 14 - 29
switch will supply a ground circuit to the powertrain control module (PCM). The switch is available only with 4.0L engine when supplied with the optional police package.
CRUISE MODE
When the engine is at operating temperature, this is a Closed Loop mode. At cruising speed, the powertrain control module (PCM) receives inputs from:
• Air conditioning select signal (if equipped)
•
Air conditioning request signal (if equipped)
•
Battery voltage
•
Engine coolant temperature sensor
•
Crankshaft position sensor
• Intake manifold air temperature sensor
• Manifold absolute pressure (MAP) sensor
• Throttle position sensor (TPS)
• Camshaft position sensor signal (in the distributor)
• Park/Neutral switch (gear indicator signal—auto.
trans. only)
• Oxygen (O2S) sensor
Based on these inputs, the following occurs:
• Voltage is applied to the fuel injectors with the
PCM. The PCM will then adjust the injector pulse width by turning the ground circuit to each individual injector on and off.
• The PCM monitors the O2S sensor input and adjusts air-fuel ratio. It also adjusts engine idle speed through the idle air control (IAC) motor.
• The PCM adjusts ignition timing by turning the ground path to the coil on and off.
• The PCM operates the A/C compressor clutch through the clutch relay. This happens if A/C has been selected by the vehicle operator and requested by the A/C thermostat.
ACCELERATION MODE
This is an Open Loop mode. The powertrain control module (PCM) recognizes an abrupt increase in throttle position or MAP pressure as a demand for increased engine output and vehicle acceleration.
The PCM increases injector pulse width in response to increased throttle opening.
DECELERATION MODE
When the engine is at operating temperature, this is an Open Loop mode. During hard deceleration, the powertrain control module (PCM) receives the following inputs.
• Air conditioning select signal (if equipped)
• Air conditioning request signal (if equipped)
• Battery voltage
• Engine coolant temperature sensor
• Crankshaft position sensor
• Intake manifold air temperature sensor
• Manifold absolute pressure (MAP) sensor
• Throttle position sensor (TPS)
• Camshaft position sensor signal (in the distributor)
• Park/Neutral switch (gear indicator signal—auto.
trans. only)
If the vehicle is under hard deceleration with the proper rpm and closed throttle conditions, the PCM will ignore the oxygen sensor input signal. The PCM will enter a fuel cut-off strategy in which it will not supply battery voltage to the injectors. If a hard deceleration does not exist, the PCM will determine the proper injector pulse width and continue injection.
Based on the above inputs, the PCM will adjust engine idle speed through the idle air control (IAC) motor.
The PCM adjusts ignition timing by turning the ground path to the coil on and off.
The PCM opens the ground circuit to the A/C clutch relay to disengage the A/C compressor clutch.
This is done until the vehicle is no longer under deceleration (if the A/C system is operating).
WIDE OPEN THROTTLE MODE
This is an Open Loop mode. During wide open throttle operation, the powertrain control module
(PCM) receives the following inputs.
• Battery voltage
• Crankshaft position sensor
• Engine coolant temperature sensor
• Intake manifold air temperature sensor
• Manifold absolute pressure (MAP) sensor
• Throttle position sensor (TPS)
• Camshaft position sensor signal (in the distributor)
During wide open throttle conditions, the following occurs:
• Voltage is applied to the fuel injectors with the powertrain control module (PCM). The PCM will then control the injection sequence and injector pulse width by turning the ground circuit to each individual injector on and off. The PCM ignores the oxygen sensor input signal and provides a predetermined amount of additional fuel. This is done by adjusting injector pulse width.
• The PCM adjusts ignition timing by turning the ground path to the coil on and off.
• The PCM opens the ground circuit to the A/C clutch relay to disengage the A/C compressor clutch.
This will be done for approximately 15 seconds (if the air conditioning system is operating).
If the vehicle has a manual transmission, the upshift light is operated by the PCM.
IGNITION SWITCH OFF MODE
When ignition switch is turned to OFF position, the PCM stops operating the injectors, ignition coil,
ASD relay and fuel pump relay.
THROTTLE BODY
Filtered air from the air cleaner enters the intake manifold through the throttle body (Fig. 25). Fuel does not enter the intake manifold through the throt-
14 - 30 FUEL SYSTEM
J tle body. Fuel is sprayed into the manifold by the fuel injectors. The throttle body is mounted on the intake manifold. It contains an air control passage (Fig. 26) controlled by an Idle Air Control (IAC) motor. The air control passage is used to supply air for idle conditions. A throttle valve (plate) is used to supply air for above idle conditions.
pressure regulator is attached to the rail and the fuel pressure test port is integral with the rail. The fuel rail is not repairable.
Fig. 25 Throttle Body—Typical
Fig. 27 Fuel Rail—Typical
FUEL PRESSURE REGULATOR
The fuel pressure regulator (Fig. 28) is a mechanical device that is not controlled by the powertrain control module (PCM).
Fig. 26 Idle Air Control Passage
The throttle position sensor (TPS) and idle air control (IAC) motor are attached to the throttle body.
The accelerator pedal cable, speed control cable and transmission control cable (when equipped) are connected to the throttle arm.
A (factory adjusted) set screw is used to mechanically limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle
speed using this screw. All idle speed functions are controlled by the PCM.
FUEL RAIL
The fuel rail supplies fuel to the injectors and is mounted to the intake manifold (Fig. 27). The fuel
Fig. 28 Fuel Pressure Regulator—Typical
The fuel pressure regulator used is a vacuum balanced, nonadjustable type. The regulator is mounted on the output end of the fuel rail and is connected to intake manifold vacuum. The fuel return tube (to the fuel tank) is connected to the fuel pressure regulator.
The regulator is calibrated to maintain fuel system pressure at approximately 214 kPa (31 psi). This is with vacuum applied while the engine is at idle. Fuel pressure will be 55-69 kPa (8-10 psi) higher if vacuum is not applied to the regulator.
The pressure regulator contains a diaphragm, calibrated spring and a fuel return valve (Fig. 29). Fuel pressure operates on one side of the regulator, while spring pressure and intake manifold vacuum operate on the other side. Spring pressure on one side of the
J diaphragm tries to force the return valve closed. Fuel pressure on other side of diaphragm, with assistance from manifold vacuum on spring side of diaphragm, act against spring pressure to open the return valve.
System fuel pressure is the amount of fuel pressure required to force against spring pressure and unseat the return valve.
Without vacuum applied to the spring side of the regulator, the spring is calibrated to open the fuel return outlet. This happens when the pressure differential between the fuel injectors and the intake manifold reaches approximately 269 kPa (39 psi).
Since manifold vacuum varies with engine operating conditions, the amount of vacuum applied to the spring side of the diaphragm varies. For this reason, fuel pressure varies, depending upon intake manifold vacuum. With low vacuum, such as during wide open throttle conditions, minimal vacuum assistance is available. Full spring pressure is exerted to seal the fuel outlet. This causes the system pressure to increase. With high vacuum, such as at engine idle or during vehicle deceleration, fuel pressure on one side of the diaphragm is balanced by intake manifold pressure. This is done on the spring side of the diaphragm and results in lower system fuel pressure.
FUEL SYSTEM 14 - 31
Fig. 29 Fuel Pressure Regulator Operation—Typical
14 - 32 FUEL SYSTEM
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MULTI-PORT FUEL INJECTION (MFI)—GENERAL DIAGNOSIS
INDEX
page
Automatic Shutdown (ASD) Relay Testing
Camshaft Position Sensor Test
. . . . . . . . . . . . . . 43
Crankshaft Position Sensor Test
Diagnostic Trouble Code (DTC)
. . . . . . . . . . . . . . 51
DRB Scan Tool
. . . . . . . . . . . . . . . . . . . . . . . . . . 51
Engine Coolant Temperature Sensor Test
Extended Idle Switch Test
. . . . . . . . . . . . . . . . . . 45
Fuel Pump Relay Testing
. . . . . . . . . . . . . . . . . . 44
Fuel System Pressure Test
. . . . . . . . . . . . . . . . . 48
General Information
. . . . . . . . . . . . . . . . . . . . . . . 32
Idle Air Control Motor Test
. . . . . . . . . . . . . . . . . 46
Injector Test
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Intake Air Temperature Sensor Test
page
Manifold Absolute Pressure (MAP) Sensor Test
On-Board Diagnostics (OBD)
. . . . . . . . . . . . . . . . 48
Oxygen Sensor (O2S) Heating Element Test
Powertrain Control Module (PCM) 60-Way
Connector
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Relays—Operation/Testing
. . . . . . . . . . . . . . . . . . 47
Starter Motor Relay Test
. . . . . . . . . . . . . . . . . . . 48
System Schematics
. . . . . . . . . . . . . . . . . . . . . . . 38
Throttle Position Sensor (TPS) Test
Torque Converter Clutch Relay Test
Vehicle Speed Sensor Test
. . . . . . . . . . . . . . . . . 45
Visual Inspection
. . . . . . . . . . . . . . . . . . . . . . . . . 32
GENERAL INFORMATION
All 2.5L 4 cylinder and 4.0L 6 cylinder engines are equipped with sequential Multi-Port Fuel Injection
(MFI). The MFI system provides precise air/fuel ratios for all driving conditions.
VISUAL INSPECTION
A visual inspection for loose, disconnected, or incorrectly routed wires and hoses should be made. This should be done before attempting to diagnose or service the fuel injection system. A visual check will help spot these faults and save unnecessary test and diagnostic time. A thorough visual inspection will include the following checks:
(1) Verify that the 60-way connector is fully inserted into the connector of the Powertrain Control Module
(PCM) (Figs. 1 or 2). Verify that the connector mounting bolt is tightened to 4 N z m (35 in. lbs.) torque.
Fig. 2 PCM—XJ Models radiator fan relay (if equipped) connections. Inspect starter motor relay connections. Inspect relays for signs of physical damage and corrosion. The relays are installed in the
Power Distribution Center (PDC) (Figs. 3 or 4).
Fig. 1 PCM—YJ Models
(2) Inspect the battery cable connections. Be sure they are clean and tight.
(3) Inspect fuel pump relay and air conditioning compressor clutch relay (if equipped). Inspect ASD relay and
Fig. 3 PDC—YJ Models
J
Fig. 4 PDC—XJ Models
(4) Inspect ignition coil connections. Verify that coil secondary cable is firmly connected to coil (Figs.
5 or 6).
FUEL SYSTEM 14 - 33
(5) Verify that distributor cap is correctly attached to distributor. Be sure that spark plug cables are firmly connected to the distributor cap and the spark plugs in their correct firing order. Be sure that coil cable is firmly connected to distributor cap and coil.
Be sure that camshaft position sensor wire connector is firmly connected to harness connector (Figs. 7 or
8). Inspect spark plug condition. Refer to Group 8D,
Ignition System. Connect vehicle to an oscilloscope and inspect spark events for fouled or damaged spark plugs or cables.
Fig. 7 Distributor and Wiring—2.5L Engine
Fig. 5 Ignition Coil—2.5L Engine
Fig. 6 Ignition Coil—4.0L Engine
Fig. 8 Distributor and Wiring—4.0L Engine
(6) Verify that generator output wire, generator connector and ground wire are firmly connected to the generator (Fig. 9).
(7) Inspect the system ground connections at the cylinder block behind the engine oil dipstick tube
(Fig. 10).
14 - 34 FUEL SYSTEM
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Fig. 9 Generator Connector and Output Wire
Connections—Typical
Fig. 12 CCV System—4.0L Engine
(9) Verify that vacuum hose is firmly connected to fuel pressure regulator and manifold fitting (Figs. 13 or 14).
Fig. 10 System Ground Connections—Typical
(8) Verify that crankcase ventilation (CCV) fresh air hose is firmly connected to cylinder head and air cleaner covers (Figs. 11 or 12).
Fig. 13 Pressure Regulator Vacuum Hose—2.5L
Engine
Fig. 11 CCV System—2.5L Engine Fig. 14 Pressure Regulator Vacuum Hose—4.0L
Engine
J
(10) Inspect fuel tube quick-connect fitting-to-fuel rail connections (Fig. 15).
FUEL SYSTEM 14 - 35
Fig. 15 Fuel Supply Tube—Typical
(11) Verify that hose connections to all ports of vacuum fittings on intake manifold are tight and not leaking.
(12) Inspect accelerator cable, transmission throttle cable (if equipped) and cruise control cable connections (if equipped). Check their connections to the throttle arm of throttle body for any binding or restrictions (Fig. 16).
Fig. 17 Brake Vacuum Booster Hose—Typical
Fig. 16 Throttle Body Cables—Typical
(13) If equipped with vacuum brake booster, verify that vacuum booster hose is firmly connected to fitting on intake manifold. Also check connection to brake vacuum booster (Fig. 17).
(14) On XJ models equipped with 4.0L engine and
A/C, verify that auxiliary cooling fan wire connector is firmly connected to harness (Fig. 18).
(15) Inspect the air cleaner inlet and air filter element for restrictions.
(16) Inspect radiator grille area, radiator fins and air conditioning condenser for restrictions.
Fig. 18 Auxiliary Cooling Fan Connector—XJ with
4.0L Engine
(17) Verify that intake manifold air temperature sensor wire connector is firmly connected to harness connector (Figs. 19 or 20).
(18) Inspect engine ground strap connections at dash panel and rear cylinder head bolt (Fig. 21).
(19) Verify that MAP sensor electrical connector is firmly connected to MAP sensor (Fig. 22). Verify that vacuum hose is firmly connected to MAP sensor and to the intake manifold.
(20) Verify that fuel injector wire harness connectors are firmly connected to the fuel injectors in the correct order. Each harness connector is tagged with the number of its corresponding fuel injector (Fig.
23).
14 - 36 FUEL SYSTEM
Fig. 19 Sensor Location—4.0L Engine Fig. 22 MAP Sensor—Typical
Fig. 20 Sensor Location—2.5L Engine
Fig. 23 Fuel Injector Wire Harness—Typical
Fig. 21 Engine Ground Strap Connections—Typical
(21) Verify that harness connectors are firmly connected to idle air control (IAC) motor and throttle position sensor (TPS) (Figs. 19, 20 or 24).
Fig. 24 IAC Motor and TPS—2.5L Engine
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FUEL SYSTEM 14 - 37
(22) Verify that wire harness connector is firmly connected to the coolant temperature sensor (Fig.
25).
(24) Raise and support the vehicle.
(25) Inspect for pinched or leaking fuel tubes. Inspect for pinched cracked or leaking fuel hoses.
(26) Inspect for exhaust system restrictions such as pinched exhaust pipes, collapsed muffler or plugged catalytic convertor.
(27) If equipped with automatic transmission, verify that electrical harness is firmly connected to park/neutral safety switch.
Refer to Automatic
Transmission section of Group 21.
(28) Verify that the harness connector is firmly connected to the vehicle speed sensor (Fig. 27).
Fig. 25 Coolant Temperature Sensor—Typical
(23) Verify that oxygen sensor wire connector is firmly connected to the sensor. Inspect sensor and connector for damage (Fig. 26).
Fig. 27 Vehicle Speed Sensor—Typical
Fig. 26 Oxygen Sensor Location—Typical
14 - 38 FUEL SYSTEM
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Fig. 28 Fuel Pump Module Connector and Fuel Hoses—Typical
(29) Verify that fuel pump module wire connector is firmly connected to harness connector.
(30) Inspect fuel hoses at fuel pump module for cracks or leaks (Fig. 28).
(31) Inspect transmission torque convertor housing
(automatic transmission) or clutch housing (manual transmission) for damage to timing ring on drive plate/flywheel.
(32) Verify that battery cable and solenoid feed wire connections to the starter solenoid are tight and clean. Inspect for chaffed wires or wires rubbing up against other components (Fig. 29).
POWERTRAIN CONTROL MODULE (PCM) 60-WAY
CONNECTOR
For PCM 60-way connector wiring schematics, refer to Group 8W, Wiring Diagrams.
Fig. 29 Starter Solenoid Connections—Typical
SYSTEM SCHEMATICS
Fuel system schematics for the 2.5L 4 cylinder and
4.0L 6 cylinder engines are shown in figures 30, 31,
32 and 33.
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FUEL SYSTEM 14 - 39
14 - 40 FUEL SYSTEM
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FUEL SYSTEM 14 - 41
14 - 42 FUEL SYSTEM
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FUEL SYSTEM 14 - 43
AUTOMATIC SHUT DOWN (ASD) RELAY TESTING
To perform a complete test of the ASD relay and its circuitry, refer to the DRB scan tool and appropriate Powertrain Diagnostics Procedures manual. To test the relay only, refer to Relays—Operation/Testing in this section of the group.
CAMSHAFT POSITION SENSOR TEST
Refer to Group 8D, Ignition Systems, for Camshaft
Position Sensor testing.
ENGINE COOLANT TEMPERATURE SENSOR TEST
To perform a complete test of the engine coolant temperature sensor and its circuitry, refer to DRB scan tool and appropriate Powertrain Diagnostics
Procedures manual. To test the sensor only, refer to the following:
Disconnect wire harness connector from engine coolant temperature sensor (Fig. 34).
SENSOR RESISTANCE (OHMS)—COOLANT
TEMPERATURE SENSOR/MANIFOLD AIR TEM-
PERATURE
Disconnect the wire harness connector from the intake manifold air temperature sensor (Figs. 35 or
36).
Fig. 34 Coolant Temperature Sensor—Typical
Test the resistance of the sensor with a high input impedance (digital) volt-ohmmeter. The resistance should be less than 1000 ohms with the engine at its correct operating temperature. Refer to the Coolant
Temperature Sensor/Manifold Air Temperature Sensor resistance chart. Replace the sensor if it is not within the range of resistance specified in the chart.
Test continuity of the wire harness. Do this between the Powertrain Control Module (PCM) wire harness connector terminal-2 and the sensor connector terminal. Also test continuity of wire harness terminal-4 to the sensor connector terminal. Repair the wire harness if an open circuit is indicated.
INTAKE AIR TEMPERATURE SENSOR TEST
To perform a complete test of the sensor and its circuitry, refer to DRB scan tool and appropriate Powertrain Diagnostics Procedures manual. To test the sensor only, refer to the following:
Fig. 35 Air Temperature Sensor—2.5L Engine
Test the resistance of the sensor with an input impedance (digital) volt-ohmmeter.
The resistance should be less than 4000 ohms with the engine at operating temperature. The longer the engine idles, the warmer the intake manifold temperature will become. Refer to the Coolant Temperature Sensor/Manifold Air Temperature Sensor resistance chart.
Replace the sensor if it is not within the range of resistance specified in the chart.
Test the resistance of the wire harness. Do this between the Powertrain Control Module (PCM) wire
14 - 44 FUEL SYSTEM
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Test the MAP sensor output voltage at the MAP sensor connector between terminals A and B (as marked on the sensor body) (Fig. 38). With the ignition switch ON and the engine OFF, output voltage should be 4-to-5 volts. The voltage should drop to 1.5to-2.1 volts with a neutral-hot idle speed condition.
Fig. 36 Air Temperature Sensor—4.0L Engine harness connector terminal-2 and the sensor connector terminal. Also test terminal-4 to the sensor connector terminal.
Repair the wire harness as necessary if the resistance is greater than 1 ohm.
FUEL PUMP RELAY TESTING
For testing this relay, refer to Relays—Operation/
Testing in this section of the group.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
TEST
To perform a complete test of the MAP sensor and its circuitry, refer to DRB scan tool and appropriate
Powertrain Diagnostics Procedures manual. To test the sensor only, refer to the following:
Inspect the MAP sensor vacuum hose connections at the throttle body and sensor. Repair as necessary.
CAUTION: When testing, do not remove the electrical connector from MAP sensor (Fig. 37). Be sure that the MAP sensor harness wires are not damaged by the test meter probes.
Fig. 38 MAP Sensor Connector Terminals—Typical
Test Powertrain Control Module (PCM) (terminal-5) for the same voltage described above to verify the wire harness condition. Repair as necessary.
Test MAP sensor supply voltage at sensor connector between terminals A and C (Fig. 38) with the ignition ON and engine OFF. The voltage should be approximately 5 volts ( 6 0.5V). Five volts ( 6 0.5V) should also be at terminal-6 of the PCM wire harness connector. Repair or replace the wire harness as necessary.
Test the MAP sensor ground circuit at sensor connector terminal-A (Fig. 38) and PCM connector terminal-4. Repair the wire harness if necessary.
Test the MAP sensor ground circuit at the PCM connector between terminal-4 and terminal-11 with an ohmmeter. If the ohmmeter indicates an open circuit, inspect for a defective sensor ground connection.
Refer to Group 8W, Wiring for location of engine grounds. If the ground connection is good, replace the
PCM. If terminal-4 has a short circuit to 12 volts, correct this condition before replacing the PCM.
CRANKSHAFT POSITION SENSOR TEST
Refer to Group 8D, Ignition Systems for test procedures.
Fig. 37 MAP Sensor—Typical
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FUEL SYSTEM 14 - 45
EXTENDED IDLE SWITCH TEST
OPTIONAL POLICE PACKAGE ONLY
OPERATION
The extended idle switch is used to raise the engine idle speed to approximately 1000 rpm when the shifter is in either the Park or Neutral position. A rocker-type 2-wire switch (extended idle switch) is mounted to the instrument panel. This switch is available only with 4.0L engine when supplied with the optional police package.
TESTING
The extended idle switch will control a ground circuit going to the powertrain control module (PCM).
When a ground signal (through this switch) has been received at pin number 10 in the PCM, engine idle speed will increase.
Bring the engine to normal operating temperature and turn the extended idle switch to the ON position.
Engine speed should now increase to approximately
1000 rpm when the shifter is in either the Park or
Neutral position. If engine speed does not increase, apply a good ground to pin number 10 at the PCM using a small paper clip. Be careful not to damage the wiring with the paper clip. If the engine speed now increases, it can be assumed that the PCM is functioning correctly. Check the instrument panel mounted switch for a closed ground circuit when in the ON position. If the engine speed will not increase after applying a ground to pin number 10, replace the PCM. Refer to Group 8W, Wiring Diagrams for circuit and wiring information.
THROTTLE POSITION SENSOR (TPS) TEST
To perform a complete test of the sensor and its circuitry, refer to DRB scan tool and appropriate Powertrain Diagnostics Procedures manual. To test the sensor only, refer to the following:
The throttle position sensor (TPS) can be tested with a digital voltmeter. The center terminal of the
TPS is the output terminal (Figs. 39 or 40).
With the ignition key in the ON position, backprobe the TPS connector. Check the TPS output voltage at the center terminal wire of the connector.
Check this at idle (throttle plate closed) and at wide open throttle (WOT). At idle, TPS output voltage should must be greater than 200 millivolts. At wide open throttle, TPS output voltage must be less than
4.8 volts. The output voltage should increase gradually as the throttle plate is slowly opened from idle to
WOT.
TORQUE CONVERTER CLUTCH RELAY TEST
To test the relay only, refer to Relays—Operation/
Testing in this section of the group. To test the torque converter clutch circuit and related compo-
Fig. 39 TPS Testing—2.5L Engine
Fig. 40 TPS Testing—4.0L Engine nents, refer to the appropriate Powertrain Diagnostic
Procedures manual for operation of the DRB scan tool.
VEHICLE SPEED SENSOR TEST
To perform a complete test of the sensor and its circuitry, refer to DRB scan tool and appropriate Powertrain Diagnostics Procedures manual.
OXYGEN SENSOR (O2S) HEATING ELEMENT TEST
To perform a complete test of the O2S sensor (Fig.
41) and its circuitry, refer to DRB scan tool and appropriate Powertrain Diagnostics Procedures manual.
To test the sensor only, refer to the following:
The oxygen sensor heating element can be tested with an ohmmeter as follows:
With the sensor at room temperature 25 degrees C
(77 degrees F), disconnect the O2S sensor connector.
Connect the ohmmeter test leads across the white wire terminals of the sensor connector. Resistance should be between 5 and 7 ohms. Replace the sensor if the ohmmeter displays an infinity (open) reading.
14 - 46 FUEL SYSTEM
Fig. 41 Oxygen Sensor—Typical
IDLE AIR CONTROL MOTOR TEST
Idle Air Control (IAC) Motor operation can be tested using special exerciser tool number 7558 (Fig.
42).
J negative battery terminal. The red light on the exerciser tool will flash when the tool is properly connected.
(4) Start engine.
When the switch on the tool is in the HIGH or
LOW position, the light on the tool will flash. This indicates that voltage pulses are being sent to the
IAC stepper motor.
(5) Move the switch to the HIGH position. The engine speed should increase. Move the switch to the
LOW position. The engine speed should decrease.
(a) If the engine speed changes while using the exerciser tool, the IAC motor is functioning properly. Disconnect the exerciser tool and connect the
IAC motor wire connector to the stepper motor.
(b) If the engine speed does not change, turn the ignition OFF and proceed to step (6). Do not disconnect exerciser tool from the IAC motor.
(6) Remove the IAC motor from the throttle body.
Do not remove IAC motor housing from throttle body.
CAUTION: When checking IAC motor operation with the motor removed from the throttle body, do not extend the pintle (Fig. 43) more than 6.35 mm (.250
in). If the pintle is extended more than this amount, it may separate from the IAC motor. The IAC motor must be replaced if the pintle separates from the motor.
Fig. 42 IAC Motor Testing—Typical
CAUTION: Proper safety precautions must be taken when testing the idle air control motor:
•
Set the parking brake and block the drive wheels
• Route all tester cables away from the cooling fans, drive belt, pulleys and exhaust components
• Provide proper ventilation while operating the engine
• Always return the engine idle speed to normal before disconnecting the exerciser tool
(1) With the ignition OFF, disconnect the IAC motor wire connector at throttle body (Fig. 42).
(2) Plug the exerciser tool number 7558 harness connector into the IAC motor.
(3) Connect the red clip of exerciser tool 7558 to battery positive terminal. Connect the black clip to
Fig. 43 Idle Air Control (IAC) Motor Pintle
(7) With the ignition OFF, cycle the exerciser tool switch between the HIGH and LOW positions. Observe the pintle. The pintle should move in-and-out of the motor.
(a) If the pintle does not move, replace the idle air control motor. Start the engine and test the replacement motor operation as described in step (5).
(b) If the pintle operates properly, check the idle air control motor bore in the throttle body bore for blockage and clean as necessary. Reinstall the idle air control motor and retest. If blockage is not
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FUEL SYSTEM 14 - 47
found, refer to the DRB scan tool and the appropriate Powertrain Diagnostics Procedures service manual.
RELAYS—OPERATION/TESTING
OPERATION
The following operations/tests apply to these
relays only: automatic shut down (ASD), fuel pump and torque converter clutch. For operations/tests on all other relays, refer to the appropriate section of this service manual.
The relay terminal numbers from (Fig. 44) can be found on the bottom of the relay:
• Terminal number 30 is connected to battery voltage and can be switched or B+ (hot) at all times.
•
Terminal number 87A is connected (a circuit is formed) to terminal 30 in the de-energized (normally
OFF) position.
•
Terminal number 87 is connected (a circuit is formed) to terminal 30 in the energized (ON) position. Terminal number 87 then supplies battery voltage to the component being operated.
• Terminal number 86 is connected to a switched (+) power source.
• Terminal number 85 is grounded by the powertrain control module (PCM).
TESTING
(1) Remove relay before testing.
(2) Using an ohmmeter, perform a resistance test between terminals 85 and 86. Resistance value
(ohms) should be 75 6 5 ohms for resistor equipped relays.
(3) Connect the ohmmeter between terminals number 87A and 30. Continuity should be present at this time.
(4) Connect the ohmmeter between terminals number 87 and 30. Continuity should not be present at this time.
(5) Use a set of jumper wires (16 gauge or smaller). Connect one jumper wire between terminal number 85 (on the relay) to the ground side (-) of a 12
Volt power source.
(6) Attach the other jumper wire to the positive side (+) of a 12V power source. Do not connect the jumper wire to relay at this time.
CAUTION: DO NOT ALLOW THE OHMMETER TO
CONTACT TERMINALS 85 OR 86 DURING THESE
TESTS. DAMAGE TO OHMMETER MAY RESULT.
(7) Attach the other jumper wire (12V +) to terminal number 86. This will activate the relay. Continuity should now be present between terminals number
Fig. 44 Relay Terminals
14 - 48 FUEL SYSTEM
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87 and 30. Continuity should not be present between terminals number 87A and 30.
(8) Disconnect jumper wires from relay and 12
Volt power source.
If continuity or resistance tests did not pass, replace relay. If tests passed, refer to Group 8W, Wiring Diagrams for additional circuit information. Also refer to the appropriate Powertrain Diagnostic Procedures manual for operation of the DRB scan tool.
STARTER MOTOR RELAY TEST
Refer to Group 8A, Battery/Starting/Charging/System Diagnostics, for starter motor relay testing.
INJECTOR TEST
Disconnect the injector wire connector from the injector. Place an ohmmeter on the injector terminals.
Resistance reading should be approximately 14.5
ohms
6
1.2 ohms at 20°C (68°F). Proceed to following
Injector Diagnosis chart.
FUEL SYSTEM PRESSURE TEST
Refer to the Fuel Delivery System section of this group. See Fuel System Pressure Test.
ON-BOARD DIAGNOSTICS (OBD)
The Powertrain Control Module (PCM) has been programmed to monitor many different circuits of the fuel injection system. If a problem is sensed in a monitored circuit often enough to indicate an actual problem, a Diagnostic Trouble Code (DTC) is stored.
The DTC will be stored in the PCM memory for eventual display to the service technician. If the problem is repaired or ceases to exist, the PCM cancels the DTC after 51 engine starts.
Certain criteria must be met for a diagnostic trouble code (DTC) to be entered into PCM memory. The criteria may be a specific range of engine rpm, engine temperature and/or input voltage to the PCM.
It is possible that a DTC for a monitored circuit may not be entered into memory even though a malfunction has occurred. This may happen because one of the DTC criteria for the circuit has not been met.
Example: assume that one of the criteria for the
MAP sensor circuit is that the engine must be operating between 750 and 2000 rpm to be monitored for a DTC. If the MAP sensor output circuit shorts to ground when the engine rpm is above 2400 rpm, a 0 volt input will be seen by the PCM. A DTC will not be entered into memory because the condition does not occur within the specified rpm range.
A DTC indicates that the powertrain control module (PCM) has recognized an abnormal signal in a circuit or the system. A DTC may indicate the result of a failure, but never identify the failed component directly.
There are several operating conditions that the
PCM does not monitor and set a DTC for. Refer to the following Monitored Circuits and Non-Monitored
Circuits in this section.
MONITORED CIRCUITS
The powertrain control module (PCM) can detect certain problems in the fuel injection system.
Open or Shorted Circuit - The PCM can determine if sensor output (which is the input to PCM) is within proper range. It also determines if the circuit is open or shorted.
Output Device Current Flow - The PCM senses whether the output devices are hooked up.
If there is a problem with the circuit, the PCM senses whether the circuit is open, shorted to ground
(-), or shorted to (+) voltage.
Oxygen Sensor - The PCM can determine if the oxygen sensor is switching between rich and lean.
This is, once the system has entered Closed Loop. Refer to Open Loop/Closed Loop Modes Of Operation in the Component Description/System Operation section for an explanation of Closed (or Open) Loop operation.
NON-MONITORED CIRCUITS
The PCM does not monitor the following circuits, systems or conditions that could have malfunctions that result in driveability problems. A Diagnostic
Trouble Code (DTC) may not be displayed for these conditions.
Fuel Pressure: Fuel pressure is controlled by the vacuum assisted fuel pressure regulator. The PCM cannot detect a clogged fuel pump inlet filter, clogged in-line fuel filter, or a pinched fuel supply or return line. However, these could result in a rich or lean condition causing an oxygen sensor DTC to be stored in the PCM.
Secondary Ignition Circuit: The PCM cannot detect an inoperative ignition coil, fouled or worn spark plugs, ignition cross firing, or open circuited spark plug cables.
Engine Timing: The PCM cannot detect an incorrectly indexed timing chain, camshaft sprocket or crankshaft sprocket. The PCM also cannot detect an incorrectly indexed distributor. However, these could result in a rich or lean condition causing an oxygen sensor DTC to be stored in the PCM.
Cylinder Compression: The PCM cannot detect uneven, low, or high engine cylinder compression.
Exhaust System: The PCM cannot detect a plugged, restricted or leaking exhaust system.
Fuel Injector Malfunctions: The PCM cannot determine if the fuel injector is clogged, or the wrong injector is installed. However, these could result in a rich or lean condition causing an oxygen sensor DTC to be stored in the PCM.
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FUEL SYSTEM 14 - 49
INJECTOR DIAGNOSIS—VEHICLE RUNS ROUGH AND/OR HAS A MISS
14 - 50 FUEL SYSTEM
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Excessive Oil Consumption: Although the PCM monitors exhaust stream oxygen content through oxygen sensor (closed loop), it cannot determine excessive oil consumption.
Throttle Body Air Flow: The PCM cannot detect a clogged or restricted air cleaner inlet or air filter element.
Evaporative System: The PCM will not detect a restricted, plugged or loaded EVAP canister.
Vacuum Assist: Leaks or restrictions in the vacuum circuits of vacuum assisted engine control system devices are not monitored by the PCM. However, a vacuum leak at the MAP sensor will be monitored and a diagnostic trouble code (DTC) will be generated by the PCM.
Powertrain Control Module (PCM) System
Ground: The PCM cannot determine a poor system ground. However, a DTC may be generated as a result of this condition.
Powertrain Control Module (PCM) Connector
Engagement: The PCM cannot determine spread or damaged connector pins. However, a DTC may be generated as a result of this condition.
HIGH AND LOW LIMITS
The powertrain control module (PCM) compares input signal voltages from each input device. It will establish high and low limits that are programmed into it for that device. If the input voltage is not within specifications and other Diagnostic Trouble Code
(DTC) criteria are met, a DTC will be stored in memory. Other DTC criteria might include engine rpm limits or input voltages from other sensors or switches. The other inputs might have to be sensed by the PCM when it senses a high or low input voltage from the control system device in question.
ACCESSING DIAGNOSTIC TROUBLE CODES
A stored Diagnostic Trouble Code (DTC) can be displayed by cycling the ignition key On-Off-On-Off-On within three seconds and observing the Malfunction
Indicator Lamp. This lamp was formerly referred to as the Check Engine Lamp. The lamp is located on the instrument panel.
They can also be displayed through the use of the
Diagnostic Readout Box (DRB) scan tool. The DRB scan tool connects to the data link connector in the engine compartment (Figs. 45 or 46). For operation of the DRB, refer to the appropriate Powertrain Diagnostic Procedures service manual.
EXAMPLES:
• If the lamp flashes 4 times, pauses and flashes 1 more time, a flashing Diagnostic Trouble Code (DTC) number 41 is indicated.
• If the lamp flashes 4 times, pauses and flashes 6 more times, a flashing Diagnostic Trouble Code
(DTC) number 46 is indicated.
Fig. 45 Data Link Connector—YJ Models—Typical
Fig. 46 Data Link Connector—XJ Models—Typical
After any stored DTC information has been observed, the display will end with a flashing DTC number 55. This will indicate the end of all stored information.
Refer to the Diagnostic Trouble Code (DTC) charts for DTC identification.
If the problem is repaired or ceases to exist, the
Powertrain Control Module (PCM) cancels the DTC after 51 engine starts.
Diagnostic Trouble Codes indicate the results of a failure, but never identify the failed component directly.
The circuits of the data link connector are shown in (Fig. 47).
ERASING TROUBLE CODES
After the problem has been repaired, use the DRB scan tool to erase a Diagnostic Trouble Code (DTC).
Refer to the appropriate Powertrain Diagnostic Procedures service manual for operation of the DRB scan tool.
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Fig. 47 Data Link Connector Schematic
FUEL SYSTEM 14 - 51
DRB SCAN TOOL
For operation of the DRB scan tool, refer to the appropriate Powertrain Diagnostic Procedures service manual.
DIAGNOSTIC TROUBLE CODE (DTC)
On the following pages, a list of diagnostic trouble codes is provided for the 2.5L 4 cylinder and 4.0L 6 cylinder engines. A DTC indicates that the powertrain control module (PCM) has recognized an abnormal signal in a circuit or the system. A DTC may indicate the result of a failure, but never identify the failed component directly.
Diagnostic
Trouble
Code
DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
DRB Scan Tool
Display
Description of Diagnostic Trouble Code
11* . . . . . . . . . .
No Crank Reference
Signal at PCM
12* . . . . . . . . . .
Battery Disconnect
No crank reference signal detected during engine cranking.
13** . . . . . . . . . .
No Change in MAP From
Start to Run
14** . . . . . . . . . .
MAP Sensor Voltage Too
Low or
MAP Sensor Voltage Too
High
15** . . . . . . . . . .
No Vehicle Speed Sensor
Signal
17* . . . . . . . . . .
Engine is Cold Too Long
Direct battery input to PCM was disconnected within the last 50 Key-on cycles.
No difference recognized between the engine MAP reading and the barometric (atmospheric) pressure reading at start-up.
MAP sensor input below minimum acceptable voltage.
MAP sensor input above maximum acceptable voltage.
No vehicle distance (speed) sensor signal detected during road load conditions.
Engine coolant temperature remains below normal operating temperatures during vehicle travel (thermostat).
Neither rich or lean condition detected from the oxygen sensor input.
21** . . . . . . . . . .
O2S Stays at Center or
O2S Shorted to Voltage
22** . . . . . . . . . .
ECT Sensor Voltage Too
High or
Oxygen sensor input voltage maintained above the normal operating range.
Engine coolant temperature sensor input above maximum acceptable voltage.
ECT Sensor Voltage Too
Low
Engine coolant temperature sensor input below minimum acceptable voltage.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded. Cycle Ignition key as described in manual and observe code flashed by Check Engine lamp.
** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
14 - 52 FUEL SYSTEM
Diagnostic
Trouble
Code
DIAGNOSTIC TROUBLE CODE DESCRIPTIONS—CONTINUED
DRB Scan Tool
Display
Description of Diagnostic Trouble Code
23** . . . . . . . . . .
Intake Air Temp Sensor
Voltage Low or
Intake Air Temp Sensor
Voltage High
24** . . . . . . . . . .
Throttle Position Sensor
Voltage High or
Throttle Position Sensor
Voltage Low
25** . . . . . . . . . .
Idle Air Control Motor
Circuits
27* . . . . . . . . . .
Injector #1 Control Circuit or
Injector #2 Control Circuit or
Injector #3 Control Circuit or
Intake air temperature sensor input below the minimum acceptable voltage.
Intake air temperature sensor input above the maximum acceptable voltage.
Throttle position sensor input above the maximum acceptable voltage.
Throttle position sensor input below the minimum acceptable voltage.
A shorted condition detected in one or more of the idle air control motor circuits.
Injector #1 output driver does not respond properly to the control signal.
Injector #2 output driver does not respond properly to the control signal.
Injector #3 output driver does not respond properly to the control signal.
Injector #4 Control Circuit or
Injector #5 Control Circuit or
Injector #6 Control Circuit
33* . . . . . . . . . .
A/C Clutch Relay Circuit
34* . . . . . . . . . .
Speed Control Solenoid
Circuits or
Injector #4 output driver does not respond properly to the control signal.
Injector #5 output driver does not respond properly to the control signal.
Injector #6 output driver does not respond properly to the control signal.
An open or shorted condition detected in the A/C clutch relay circuit.
An open or shorted condition detected in the Speed Control vacuum or vent solenoid circuits.
Speed Control Switch
Always Low or
Speed Control Switch
Always High
35* (XJ Only) . . . .
Rad Fan Control Relay
Circuits
Speed Control switch input below the minimum acceptable voltage.
Speed Control switch input above the maximum acceptable voltage.
An open or shorted condition detected in the radiator fan relay circuit.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded. Cycle Ignition key as described in manual and observe code flashed by Check Engine lamp.
** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
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FUEL SYSTEM 14 - 53
Diagnostic
Trouble
Code
DIAGNOSTIC TROUBLE CODE DESCRIPTIONS—CONTINUED
DRB Scan Tool
Display
Description of Diagnostic Trouble Code
41** . . . . . . . . . .
Generator Field Not
Switching Properly
42* . . . . . . . . . .
Auto Shutdown Relay
Control Circuit
44* . . . . . . . . . .
46** . . . . . . . . . .
47** . . . . . . . . . .
Battery Temp Sensor
Volts out of Limit
Charging System Voltage
Too High
Charging System Voltage
Too Low
51** . . . . . . . . . .
O2S Signal Stays Below
Center (Lean)
52** . . . . . . . . . .
O2S Signal Stays Above
Center (Rich)
53* . . . . . . . . . .
Internal PCM Failure or
An open or shorted condition detected in the generator field control circuit.
An open or shorted condition detected in the auto shutdown relay circuit.
An open or shorted condition exists in the engine coolant temperature sensor circuit or a problem exists in the PCM’s battery temperature voltage circuit.
Battery voltage sense input above target charging voltage during engine operation.
Battery voltage sense input below target charging during engine operation.
Also, no significant change detected in battery voltage during active test of generator output.
Oxygen sensor signal input indicates lean air/fuel ratio condition during engine operation.
Oxygen sensor signal input indicates rich air/fuel ratio condition during engine operation.
PCM Internal fault condition detected.
PCM Failure SPI
Communications
54* . . . . . . . . . .
No Cam Sync Signal at
PCM
55* . . . . . . . . . .
N/A
PCM Internal fault condition detected.
No fuel sync (camshaft signal) detected during engine cranking.
Completion of diagnostic trouble code display on the Malfunction Indicator
Lamp (Check Engine Lamp).
Unsuccessful attempt to update SPI miles in the PCM EEPROM.
62* . . . . . . . . . .
PCM Failure SPI miles not stored
63* . . . . . . . . . .
PCM Failure EEPROM
Write Denied
Unsuccessful attempt to write to an EEPROM location by the PCM.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded. Cycle Ignition key as described in manual and observe code flashed by Check Engine lamp.
** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
14 - 54 FUEL SYSTEM
MULTI-PORT FUEL INJECTION (MFI)—COMPONENT REMOVAL/INSTALLATION
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INDEX
page
Accelerator Pedal and Throttle Cable
Air Cleaner Housing
. . . . . . . . . . . . . . . . . . . . . . 54
Air Conditioning (A/C) Clutch Relay
Air Filter
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Automatic Shut Down (ASD) Relay
Brake Switch
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Camshaft Position Sensor
. . . . . . . . . . . . . . . . . . 54
Crankshaft Position Sensor
. . . . . . . . . . . . . . . . . 55
Engine Coolant Temperature Sensor
Fuel Filter
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Fuel Injector
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Fuel Pump Module
. . . . . . . . . . . . . . . . . . . . . . . 56
Fuel Pump Relay
. . . . . . . . . . . . . . . . . . . . . . . . 56
Fuel Rail Assembly
. . . . . . . . . . . . . . . . . . . . . . . 56
Fuel System Pressure Release Procedure
Fuel Tank Pressure Relief/Rollover Valve
Fuel Tanks
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
page
Fuel Tubes/Lines/Hoses and Clamps
Idle Air Control (IAC) Motor
. . . . . . . . . . . . . . . . . 56
Ignition Coil
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Intake Air Temperature Sensor
. . . . . . . . . . . . . . 54
Intake Manifold
. . . . . . . . . . . . . . . . . . . . . . . . . . 57
Manifold Absolute Pressure (MAP) Sensor
Oxygen (O2S) Sensor
. . . . . . . . . . . . . . . . . . . . . 57
Park Neutral Switch
. . . . . . . . . . . . . . . . . . . . . . . 58
Power Steering Pressure Switch—2.5L
Engine Only
. . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Powertrain Control Module (PCM)
Quick-Connect Fittings
. . . . . . . . . . . . . . . . . . . . . 59
Throttle Body
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Throttle Position Sensor (TPS)
. . . . . . . . . . . . . . 59
Torque Converter Clutch Relay
. . . . . . . . . . . . . . 60
Vehicle Speed Sensor
. . . . . . . . . . . . . . . . . . . . . 60
ACCELERATOR PEDAL AND THROTTLE CABLE
Refer to the Accelerator Pedal and Throttle Cable section of this group for removal/installation procedures.
AIR CONDITIONING (A/C) CLUTCH RELAY
The A/C clutch relay is located in the Power Distribution Center (PDC) (Figs. 1 or 2). For location of this relay within the PDC, refer to label on PDC cover.
Fig. 1 PDC—YJ Models
AIR CLEANER HOUSING
Refer to Group 25, Emission Control System.
AIR FILTER
Refer to Group 25, Emission Control System.
Fig. 2 PDC—XJ Models
AUTOMATIC SHUT DOWN (ASD) RELAY
The ASD relay is located in the Power Distribution
Center (Figs. 1 or 2) (PDC). For location of this relay within the PDC, refer to label on PDC cover.
BRAKE SWITCH
Refer to Group 5, Brakes for removal/installation procedures.
CAMSHAFT POSITION SENSOR
For removal/installation procedures, refer to Group
8D, Ignition System. See Camshaft Position Sensor.
INTAKE AIR TEMPERATURE SENSOR
The intake manifold air temperature sensor is installed into the intake manifold plenum (Figs. 3 or
4).
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FUEL SYSTEM 14 - 55
Fig. 3 Sensor Location—2.5L Engine
Fig. 4 Sensor Location—4.0L Engine
REMOVAL
(1) Disconnect the electrical connector from the sensor.
(2) Remove the sensor from the intake manifold.
INSTALLATION
(1) Install the sensor into the intake manifold.
Tighten the sensor to 28 N z m (20 ft. lbs.) torque.
(2) Connect the electrical connector to the sensor.
CRANKSHAFT POSITION SENSOR
For description, operation and removal/installation procedures, refer to Group 8D, Ignition Systems in this manual.
ENGINE COOLANT TEMPERATURE SENSOR
The coolant temperature sensor is installed in the thermostat housing (Fig. 5).
REMOVAL
(1) Drain cooling system until the coolant level is below the cylinder head. Observe the WARNINGS in
Group 7, Cooling.
Fig. 5 Engine Coolant Temperature Sensor—Typical
(2) Disconnect the coolant temperature sensor wire connector.
(3) Remove the sensor from the thermostat housing (Fig. 5).
INSTALLATION
(1) Install coolant temperature sensor into the cylinder block. Tighten to 28 N z m (21 ft. lbs.) torque.
(2) Connect the wire connector.
(3) Fill the cooling system. Refer to Group 7, Cooling System.
FUEL FILTER
Refer to the Fuel Delivery System section of this group for removal/installation procedures.
FUEL INJECTOR
REMOVAL
(1) Remove the fuel rail. Refer to Fuel Rail Removal in this section.
(2) Remove the clip(s) that retain the fuel injector(s) to the fuel rail (Fig. 6).
Fig. 6 Injector Retaining Clips
14 - 56 FUEL SYSTEM
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INSTALLATION
(1) Install the fuel injector(s) into the fuel rail assembly and install retaining clip(s).
(2) Install fuel rail. Refer to Fuel Rail Installation in this section.
(3) Start engine and check for fuel leaks.
FUEL PUMP MODULE
Refer to the Fuel Delivery System section of this group for removal/installation procedures.
FUEL PUMP RELAY
The Fuel Pump relay is located in the Power Distribution Center (PDC) (Figs. 1 or 2). For location of this relay within the PDC, refer to label on PDC cover.
FUEL RAIL ASSEMBLY
REMOVAL
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39
PSI). THIS PRESSURE MUST BE RELEASED BE-
FORE SERVICING THE FUEL RAIL.
(1) Remove fuel tank filler tube cap.
(2) Disconnect the negative battery cable from battery.
(3) Perform the Fuel System Pressure Release Procedure as described in the Fuel Delivery System section of this Group.
(4) Remove and numerically attach a tag (if fuel injector is not already tagged), the injector harness connectors. Do this at each injector (Fig. 7).
Fig. 7 Fuel Injector Harness—Typical
(5) Disconnect vacuum line from fuel pressure regulator (Fig. 7).
(6) Disconnect fuel supply line from fuel rail and the fuel return line from fuel pressure regulator (Fig.
7). Refer to Fuel Tubes/Lines/Hoses and Clamps, or
Quick-Connect Fittings. These can both be found in the Fuel Delivery section of this group.
(7) Remove fuel rail mounting bolts.
On models with automatic transmissions, it may be necessary to remove automatic transmission throttle line pressure cable (and bracket). This will aid in fuel rail assembly removal.
(8) Remove fuel rail by gently rocking until all the fuel injectors are out of the intake manifold.
INSTALLATION
(1) Position tips of all fuel injectors into the corresponding injector bore in the intake manifold. Seat injectors into manifold.
(2) Tighten fuel rail mounting bolts to 27 N z m (20 ft. lbs.) torque.
(3) Connect injector harness connectors to appropriate (tagged) injector.
(4) Connect both fuel lines to fuel rail.
(5) Connect vacuum supply line to fuel pressure regulator.
(6) Install protective cap to pressure test port fitting.
(7) Install fuel tank cap.
(8) Connect negative battery cable to battery.
(9) Start engine and check for fuel leaks.
FUEL SYSTEM PRESSURE RELEASE PROCEDURE
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF)
OF APPROXIMATELY 100 KPA (14.5 PSI). BEFORE
SERVICING THE FUEL PUMP, FUEL LINES, FUEL
FILTER OR FUEL INJECTOR, THE FUEL SYSTEM
PRESSURE MUST BE RELEASED.
Refer to the Fuel Delivery System section of this group. See Fuel Pressure Release procedure.
FUEL TANKS
Refer to the Fuel Tank section of this group for removal/installation procedures.
FUEL TANK PRESSURE RELIEF/ROLLOVER VALVE
Refer to the Fuel Tank section of this group for removal/installation procedures.
FUEL TUBES/LINES/HOSES AND CLAMPS
Refer to the Fuel Delivery System section of this group for removal/installation procedures. Also refer to Quick-Connect Fittings in the Fuel Delivery section of this group.
IDLE AIR CONTROL (IAC) MOTOR
The IAC motor is mounted to the throttle body adjacent to the throttle position sensor (Fig. 8).
J
REMOVAL
(1) Disconnect the electrical connector from the
IAC motor.
FUEL SYSTEM 14 - 57
Fig. 8 Idle Air Control
Motor—Removal/Installation—Typical
(2) Remove IAC motor torx head mounting bolts.
(3) Remove IAC motor.
INSTALLATION
(1) Install IAC motor into throttle body and tighten retaining bolts.
(2) Connect electrical connector to IAC motor.
IGNITION COIL
Refer to Group 8D, Ignition Systems for removal/ installation procedures.
INTAKE MANIFOLD
Refer to Group 11, Exhaust System and Intake
Manifold for removal/installation procedures.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
The MAP sensor is located on the dash panel near the rear of the engine cylinder head (valve) cover
(Fig. 9).
REMOVAL
(1) Disconnect the MAP sensor electrical connector
(Fig. 9).
(2) Disconnect the MAP sensor vacuum supply hose (Fig. 9).
(3) Remove the MAP sensor mounting bolts and remove MAP sensor.
INSTALLATION
(1) Install MAP sensor to dash panel and secure with mounting bolts.
(2) Install the MAP sensor vacuum supply hose.
(3) Connect the MAP sensor electrical connector.
Fig. 9 MAP Sensor—Typical
OXYGEN (O2S) SENSOR
The O2S sensor is installed in the exhaust down pipe just below the exhaust manifold flange (Fig. 10).
Fig. 10 Oxygen Sensor—Typical
REMOVAL
WARNING: THE EXHAUST MANIFOLD BECOMES
VERY HOT DURING ENGINE OPERATION. ALLOW
ENGINE TO COOL BEFORE REMOVING OXYGEN
SENSOR.
(1) Raise and support the vehicle.
(2) Separate the electrical connectors.
(3) Remove the O2S sensor from the exhaust manifold. Snap-On oxygen sensor wrench (number YA
8875) may be used for removal and installation.
INSTALLATION
Threads of new factory oxygen sensors are coated with anti-seize compound to aid in removal.
(1) Install the O2S sensor into the exhaust manifold and tighten to 30 N z m (22 ft. lbs.) torque.
(2) Connect the O2S sensor wire connector to the main harness.
14 - 58 FUEL SYSTEM
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(3) Lower the vehicle.
PARK NEUTRAL SWITCH
Refer to Group 21, Transmissions for park neutral switch service.
POWER STEERING PRESSURE SWITCH—2.5L
ENGINE ONLY
The power steering pressure switch is installed in the power steering high pressure hose (Figs. 11 or
12).
(3) Check power steering fluid and add as necessary.
(4) Start the engine and again check power steering fluid. Add fluid if necessary.
POWERTRAIN CONTROL MODULE (PCM)
On XJ models, the PCM is located in the engine compartment next to the air cleaner (Fig. 13). On YJ models, the PCM is located in the engine compartment behind the windshield washer fluid reservoir
(Fig. 14).
Fig. 11 Power Steering Pressure Switch—YJ Models
Fig. 13 PCM Location—XJ Models
Fig. 12 Power Steering Pressure Switch—XJ Models
REMOVAL
(1) Disconnect the electrical connector from the power steering pressure switch.
(2) Place a small container or shop towel beneath the switch to collect any excess fluid.
(3) Remove the switch.
INSTALLATION
(1) Install the power steering switch.
(2) Connect the electrical connector to the switch.
Fig. 14 PCM Location—YJ Models
REMOVAL
(1) Disconnect the negative battery cable at the battery.
(2) YJ Models Only: Remove the windshield washer fluid tank.
(3) Loosen the 60-Way connector mounting bolt
(Figs. 13 or 14).
(4) Remove the electrical connector by pulling straight back.
(5) Remove the three PCM mounting bolts.
(6) Remove PCM.
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FUEL SYSTEM 14 - 59
INSTALLATION
(1) After the PCM electrical connector has been separated from the PCM, inspect the pins for corrosion, being spread apart, bent or misaligned. Also inspect the pin heights in the connector. If the pin heights are different, this would indicate a pin has separated from the connector. Repair as necessary.
(2) Install PCM. Tighten three mounting bolts to 1
N z m (9 in. lbs.) torque.
(3) Engage 60-way connector into PCM. Tighten connector mounting bolt to 4 N z m (35 in. lbs.) torque.
(4) YJ Models: Install windshield washer fluid tank.
(5) Connect negative cable to battery.
QUICK-CONNECT FITTINGS
Refer to the Fuel Delivery System section of this group for removal/installation procedures.
THROTTLE BODY
REMOVAL
(1) Disconnect the negative battery cable.
(2) Disconnect air cleaner hose from throttle body.
(3) Disconnect idle air control motor and throttle position sensor wire connectors.
(4) Disconnect accelerator cable, throttle cable (automatic transmission) and speed control cable (if equipped) from throttle arm (Fig. 15).
Fig. 16 Throttle
Body—Removal/Installation—Typical
CAUTION: When the automatic transmission throttle cable is connected, it MUST be adjusted.
(4) If equipped with an automatic transmission, connect and adjust the transmission line pressure cable. Refer to Group 21, Transmissions for adjustment procedure.
(5) Install air cleaner hose to throttle body.
(6) Connect negative battery cable to battery.
THROTTLE POSITION SENSOR (TPS)
The TPS is mounted to the throttle body (Figs. 17 or 18).
Fig. 15 Cables at Throttle Body
(5) Remove throttle body mounting bolts, throttle body and gasket. Discard old gasket (Fig. 16).
INSTALLATION
(1) Install throttle body and new gasket. Tighten throttle body mounting bolts to 12 N z m (9 ft. lbs.) torque.
(2) Connect idle air control motor and throttle position sensor wire connectors.
(3) Connect throttle linkage to throttle arm.
Fig. 17 TPS Location—2.5L Engine
REMOVAL
(1) Disconnect TPS electrical connector.
(2) Remove TPS mounting bolts.
(3) Remove TPS.
INSTALLATION
The throttle shaft end of the throttle body slides into a socket in the TPS (Fig. 19). The TPS must be installed so that it can be rotated a few degrees. (If
14 - 60 FUEL SYSTEM
J
Fig. 18 TPS Location—4.0L Engine the sensor will not rotate, install the sensor with the throttle shaft on the other side of the socket tangs).
The TPS will be under slight tension when rotated.
Fig. 20 TCC Relay Location—YJ Models
Fig. 21 Power Distribution Center—XJ Models
REMOVAL
Fig. 19 Throttle Position Sensor—Installation
(1) Install the TPS and retaining bolts.
(2) Connect TPS electrical connector to TPS.
(3) Manually operate the throttle (by hand) to check for any TPS binding before starting the engine.
TORQUE CONVERTER CLUTCH RELAY
On YJ models, the TCC relay is located in the engine compartment. It is attached to the cowl panel with one bolt (Fig. 20). On XJ models, the TCC relay is located in the power distribution center (PDC)
(Fig. 21). For location of this relay within the PDC, refer to label on PDC cover.
VEHICLE SPEED SENSOR
The vehicle speed sensor (Fig. 22) is located on the extension housing of the transmission on 2WD models. It is located on the transfer case on 4WD models.
Fig. 22 Vehicle Speed Sensor Location—Typical
(1) Raise and support vehicle.
(2) Disconnect the electrical connector from the sensor.
(3) Remove the sensor mounting bolt (Fig. 23).
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Fig. 23 Sensor Removal/Installation—Typical
FUEL SYSTEM 14 - 61
(4) Remove the sensor (pull straight out) from the speedometer pinion gear adapter (Fig. 23). Do not remove the gear adapter from the transmission.
INSTALLATION
(1) Clean the inside of speedometer pinion gear adapter before installing speed sensor.
(2) Install sensor into speedometer gear adapter and install mounting bolt. Before tightening bolt, verify speed sensor is fully seated (mounted flush) to speedometer pinion gear adapter.
(3) Tighten sensor mounting bolt to 2.2 N z m (20 in.
lbs.) torque.
(4) Connect electrical connector to sensor.
14 - 62 FUEL SYSTEM
SPECIFICATIONS
GENERAL INFORMATION
The following specifications are published from the latest information available at the time of publication. If anything differs between the specifica- tions found on the Vehicle Emission Control
Information (VECI) label and the following specifications, use specifications on VECI label.
The VECI label is located in the engine compartment.
FUEL TANK CAPACITIES
TORQUE
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FUEL SYSTEM
J
BRAKES 5 - 1
BRAKES
CONTENTS page
ABS BRAKE DIAGNOSIS
. . . . . . . . . . . . . . . . . . 3
ABS COMPONENT SERVICE
. . . . . . . . . . . . . . 47
ABS SYSTEM OPERATION
. . . . . . . . . . . . . . . 39
ANTILOCK BRAKE SYSTEM OPERATION
. . . . 43
BRAKE BLEEDING—BRAKE FLUID AND
LEVEL—BRAKELINES AND HOSES
. . . . . . . 13
BRAKE PEDAL AND BRAKELIGHT SWITCH
. . 65
DISC BRAKES . . . . . . . . . . . . . . . . . . . . . . . . . . 24
page
DRUM BRAKES
. . . . . . . . . . . . . . . . . . . . . . . . 34
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1
PARKING BRAKES
. . . . . . . . . . . . . . . . . . . . . . 56
POWER BRAKE BOOSTER
. . . . . . . . . . . . . . . . 22
SERVICE BRAKE DIAGNOSIS
. . . . . . . . . . . . . . 7
SPECIFICATIONS
. . . . . . . . . . . . . . . . . . . . . . . 67
STANDARD MASTER CYLINDER
. . . . . . . . . . . 20
GENERAL INFORMATION
INDEX
page
Antilock Brake System (ABS)
. . . . . . . . . . . . . . . . 1
Brake Fluid/Lubricants/Cleaning Solvents
Brake Safety Precautions
. . . . . . . . . . . . . . . . . . . 2
Brake Warning Lights
. . . . . . . . . . . . . . . . . . . . . . 1
Brakelining Material
. . . . . . . . . . . . . . . . . . . . . . . . 1
page
Hydraulic Components
. . . . . . . . . . . . . . . . . . . . . 1
Jeep Body Code Letters
. . . . . . . . . . . . . . . . . . . . 2
Power Brakes
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Wheel Brake Components
. . . . . . . . . . . . . . . . . . . 1
WHEEL BRAKE COMPONENTS
Front disc and rear drum brakes are used on all models. The disc brake components consist of single piston calipers and ventilated rotors. The rear drum brakes are dual shoe, units with cast brake drums.
The parking brake mechanism is lever and cable operated. The cables are attached to actuating levers mounted on the rear drum brake secondary shoes.
The parking brake mechanism is operated by a foot pedal on YJ models and a hand lever on XJ models.
POWER BRAKES
Power brakes are standard on all models. A vacuum operated power booster is used for standard and
ABS brake applications.
HYDRAULIC COMPONENTS
A dual reservoir master cylinder is used for all standard brake applications. A combination proportioning valve/pressure differential switch is used. A center feed style master cylinder is used for ABS brake applications.
BRAKELINING MATERIAL
The factory installed brakelining on all models consists of an organic base material combined with metallic particles. The lining does not contain asbestos.
BRAKE WARNING LIGHTS
A red, brake warning light is used to alert the driver if a pressure differential exists between the front and rear hydraulic systems. The light also alerts the driver when the parking brakes are applied. The light illuminates for a few seconds at start up as part of a bulb check procedure.
An additional warning light is used on models with antilock brakes. This light is amber in color and is located in the same side of the instrument cluster as the red warning light. The amber light illuminates only when an ABS system fault occurs.
ANTILOCK BRAKE SYSTEM (ABS)
An antilock brake system (ABS) is available on
XJ/YJ models. The system is an electronically operated, all-wheel brake control system. The ABS system is designed to retard wheel lockup during periods of high wheel slip braking. Refer to the antilock brake section for operation and service information.
BRAKE FLUID/LUBRICANTS/CLEANING SOLVENTS
Recommended fluid for all Jeep vehicles is Mopar
DOT 3 brake fluid, or an equivalent meeting SAE
J1703 and DOT 3 standards.
5 - 2 BRAKES
J
Use Mopar Multi Mileage grease to lubricate drum brake pivot pins and rear brakeshoe contact points on the support plates. Use GE 661, or Dow 111 silicone grease on caliper bushings and mounting bolts.
Use fresh brake fluid or Mopar brake cleaner to clean or flush brake system components. These are the only cleaning materials recommended.
CAUTION: Never use gasoline, kerosene, methyl or isopropyl alcohol, paint thinner, or any fluid containing mineral oil to clean the system components.
These fluids damage rubber cups and seals. If system contamination is suspected, check the fluid for dirt, discoloration, or separation into distinct layers.
Drain and flush the system with new brake fluid if contamination is suspected.
JEEP BODY CODE LETTERS
The body/model identification code letters for Jeep vehicles are as follows:
• Code letters XJ: Cherokee
• Code letters YJ: Wrangler/YJ
The code letters are used throughout this group to simplify model identification and component application.
BRAKE SAFETY PRECAUTIONS
WARNING: ALTHOUGH FACTORY INSTALLED
BRAKELINING ON JEEP VEHICLES IS MADE FROM
ASBESTOS FREE MATERIALS, SOME AFTER MARKET
BRAKELINING MAY CONTAIN ASBESTOS.
THIS
SHOULD BE TAKEN INTO ACCOUNT WHEN REPAIR-
ING A VEHICLE WITH PRIOR BRAKE SERVICE. WEAR
A RESPIRATOR WHEN CLEANING BRAKE COMPO-
NENTS AS ASBESTOS FIBERS CAN BE A HEALTH
HAZARD. NEVER CLEAN WHEEL BRAKE COMPO-
NENTS WITH COMPRESSED AIR. USE A VACUUM
CLEANER SPECIFICALLY DESIGNED FOR REMOVING
BRAKE DUST. IF A VACUUM CLEANER IS NOT AVAIL-
ABLE, CLEAN THE PARTS WITH WATER DAMPENED
SHOP RAGS. DO NOT CREATE DUST BY SANDING
BRAKELINING. DISPOSE OF ALL DUST AND DIRT
SUSPECTED OF CONTAINING ASBESTOS FIBERS IN
SEALED BAGS OR CONTAINERS. FOLLOW ALL REC-
OMMENDED SAFETY PRACTICES PRESCRIBED BY
THE OCCUPATIONAL SAFETY AND HEALTH ADMINIS-
TRATION (OSHA) AND THE ENVIRONMENTAL PRO-
TECTION AGENCY (EPA), FOR HANDLING AND
DISPOSAL OF PRODUCTS CONTAINING ASBESTOS.
J
BRAKES 5 - 3
ABS BRAKE DIAGNOSIS
INDEX
page
ABS Fault Diagnosis
. . . . . . . . . . . . . . . . . . . . . . . 4
ABS System Wiring and Electrical Circuits
ABS Warning Light Display
. . . . . . . . . . . . . . . . . . 3
Brake Warning Light Display
. . . . . . . . . . . . . . . . . 4
Diagnosis Procedures
. . . . . . . . . . . . . . . . . . . . . . 3
ECU Diagnosis
. . . . . . . . . . . . . . . . . . . . . . . . . . . 4
HCU Diagnosis
. . . . . . . . . . . . . . . . . . . . . . . . . . . 4
page
Loss of Sensor Input
. . . . . . . . . . . . . . . . . . . . . . . 3
Operating Sound Levels
. . . . . . . . . . . . . . . . . . . . 3
Rear Speed Sensor Air Gap
. . . . . . . . . . . . . . . . . 3
Steering Response
. . . . . . . . . . . . . . . . . . . . . . . . 3
Vehicle Response in Antilock Mode
Wheel/Tire Size and Input Signals
DIAGNOSIS PROCEDURES
ABS diagnosis involves three basic steps. First is observation of the warning light display. Second is a visual examination for low fluid level, leaks, parking brakes applied, or obvious damage to system components or wires. The third step involves using the
DRB II scan tool to identify a faulty component.
The visual examination requires a check of reservoir fluid level and all system components. Things to look for are leaks, loose connections, or obvious component damage.
The final diagnosis step involves using the DRB II scan tool to determine the specific circuit or component at fault. The tester is connected to the ABS diagnostic connector in the passenger compartment.
The connector is at the driver side of the center console under the instrument panel. Refer to the DRB II scan tool Manual for tester procedures. Also refer to the ABS Fault Diagnosis charts at the end of this section for additional diagnosis information.
Initial faults should be cleared and the vehicle road tested to reset any faults that remain in the system.
Faults can be cleared with the DRB II scan tool.
REAR SPEED SENSOR AIR GAP
The front wheel sensors are fixed and cannot be adjusted. Only the rear sensor air gap is adjustable. Air gap must be set with a brass feeler gauge.
Correct air gap is important to proper signal generation. An air gap that is too large may cause complete loss of sensor input. Or, a gap that is too small could produce a false input signal, or damaging contact between the sensor and tone ring.
WHEEL/TIRE SIZE AND INPUT SIGNALS
Antilock system operation is dependant on accurate signals from the wheel speed sensors. Ideally, the vehicle wheels and tires should all be the same size and type. However, the Jeep ABS system is designed to function with a compact spare tire installed.
OPERATING SOUND LEVELS
The ABS pump and solenoid valves may produce some sound as they cycle on and off. This is a normal condition and should not be mistaken for faulty operation.
VEHICLE RESPONSE IN ANTILOCK MODE
During antilock braking, the HCU solenoid valves cycle rapidly in response to ECU inputs.
The driver will experience a pulsing sensation within the vehicle as the solenoids decrease, hold, or increase pressure as needed. A pulsing brake pedal will also be noted.
The pulsing sensation occurs as the solenoids cycle during antilock mode braking. A slight pulse in the brake pedal may also be noted during the dynamic self check part of system initialization.
STEERING RESPONSE
A modest amount of steering input is required during extremely high deceleration braking, or when braking on differing traction surfaces. An example of differing traction surfaces would be when the left side wheels are on ice and the right side wheels are on dry pavement.
LOSS OF SENSOR INPUT
Sensor malfunctions will most likely be due to loose connections, damaged sensor wires, incorrect rear sensor air gap, or a malfunctioning sensor. Additional causes of sensor faults would be sensor and tone ring misalignment or damage.
ABS WARNING LIGHT DISPLAY
ABS Light Illuminates At Startup
The amber ABS light illuminates at startup as part of the system self check feature. The light illuminates for 2-3 seconds then goes off as part of the normal self check routine.
ABS Light Remains On After Startup
An ABS system fault is indicated when the light remains on after startup. Diagnosis with the DRB II
5 - 4 BRAKES
J scan tool will be necessary to determine which ABS component has malfunctioned.
ABS Light Illuminates During Brake Stop
A system fault such as loss of speed sensor signal or solenoid failure, will cause the amber warning light to illuminate. The most effective procedure here is to check for obvious damage first. Then check the electronic components with the DRB II scan tool.
BRAKE WARNING LIGHT DISPLAY
The red brake warning light and the ABS light operate independently. If the red light remains on after startup or illuminates during a brake stop, refer to the standard brake system diagnosis section. Either the parking brakes are applied, or a wheel brake malfunction has occurred.
ECU DIAGNOSIS
The ECU controls all phases of antilock system operation. It also differentiates between normal and antilock mode braking.
The ECU monitors and processes the signals generated from all of the system sensors at all times.
The ECU program includes a self check routine that tests each of the system components. The self check occurs during both phases of the initialization program. A failure of the self check program will cause the immediate illumination of the amber warning light. The light will also illuminate if a solenoid or other system component fails during the dynamic phase of initialization.
If a system malfunction should occur, do not immediately replace the ECU. A blown system fuse, bad chassis ground, or loss of feed voltage will each cause a system malfunction similar to an ECU failure.
Never replace the ECU unless diagnosis with the
DRB II scan tool indicates this is necessary.
HCU DIAGNOSIS
The HCU pump and motor and solenoid valve body are serviced only as an assembly. The HCU assembly should not be replaced unless a fault has actually been confirmed. Verify fault conditions with the DRB
II scan tool before proceeding with repair.
ABS SYSTEM WIRING AND ELECTRICAL CIRCUITS
Location of the ABS fuse (in the fuse panel) is shown in Figure 1. The engine compartment harness routing for the ABS components is shown in Figure 2.
Fig. 1 ABS Fuse Location
ABS FAULT DIAGNOSIS
The fault diagnosis chart provides additional information on potential ABS system faults. Use the chart as a guide when diagnosing a system problem.
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BRAKES 5 - 5
Fig. 2 ABS Engine Compartment Harness Routing (XJ)
5 - 6 BRAKES
ABS FAULT DIAGNOSIS
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BRAKES 5 - 7
SERVICE BRAKE DIAGNOSIS
INDEX
page
Component Inspection
. . . . . . . . . . . . . . . . . . . . . . 8
Diagnosing Parking Brake Problems
Diagnosing Service Brake Problems
Diagnosis Procedures
. . . . . . . . . . . . . . . . . . . . . . 7
General Information
. . . . . . . . . . . . . . . . . . . . . . . . 7
page
Master Cylinder/Power Booster Test
Power Booster Check Valve Test
Power Booster Vacuum Test
. . . . . . . . . . . . . . . . 12
Preliminary Brake Check
. . . . . . . . . . . . . . . . . . . . 7
Road Testing
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
GENERAL INFORMATION
The diagnosis information in this section covers service brake components which include:
• disc brake calipers
• disc brakeshoes
• drum brake wheel cylinders
• drum brakeshoes and brake drums
• drum brake support plates
• parking brake mechanism
• master cylinder/combination valve
• vacuum power brake booster
• brake pedal and brakelight switch
• brake warning light
DIAGNOSIS PROCEDURES
Service brake diagnosis involves determining if a problem is related to a mechanical, hydraulic or vacuum operated component.
A preliminary brake check, followed by road testing and component inspection are needed to determine a problem cause.
Road testing will either verify proper brake operation or confirm the existence of a problem. Component inspection will, in most cases, identify the actual part responsible for a problem.
The first diagnosis step is the preliminary brake check. This involves inspecting fluid level, parking brake action, wheel and tire condition, checking for obvious leaks or component damage and testing brake pedal response. A road test will confirm or deny the existence of a problem. The final diagnosis procedure involves road test analysis and a visual inspection of brake components.
PRELIMINARY BRAKE CHECK
(1) If amber antilock light is illuminated, refer to
Antilock Brake System Diagnosis. However, if red warning light is illuminated, or if neither warning light is illuminated, continue with diagnosis.
(2) Check condition of tires and wheels. Damaged wheels and worn, damaged, or underinflated tires can cause pull, shudder, tramp and a condition similar to grab.
(3) If complaint was based on noise when braking, check suspension components. Jounce front and rear of vehicle and listen for noise that might be caused by loose, worn, or damaged suspension or steering components.
(4) Inspect brake fluid level:
(a) If vehicle has one-piece master cylinder, fluid level should be to 6 mm (1/4 in.) of reservoir rim. If vehicle two-piece, removable reservoir, correct level is to top of indicator rings in reservoir.
(b) On models with ABS brakes, preferred level is to MAX mark on reservoir. Acceptable level is between MAX and MIN marks.
(c) Remember that fluid level in the front and rear reservoir compartments will decrease in proportion to normal lining wear. However, if fluid level is abnormally low, look for leaks at calipers, wheel cylinders, brakelines and master cylinder.
(5) Inspect brake fluid condition:
(a) Fluid should be reasonably clear and free of foreign material. Note that brake fluid tends to darken over time. This is normal and should not be mistaken for contamination. If fluid is clear of foreign material, it is OK.
(b) If fluid is highly discolored, or appears to contain foreign material, drain out a sample with a clean suction gun. Pour sample in a glass container and note condition.
(c) If fluid separates into layers, obviously contains oil, or a substance other than brake fluid, system seals and cups will have to be replaced and hydraulic system flushed.
(6) Check parking brake operation. Verify free movement and full release of cables and foot pedal or hand lever. Also note if vehicle was being operated with parking brake partially applied.
(7) Check brake pedal operation. Verify that pedal does not bind and has adequate free play. If pedal lacks free play, check pedal and power booster for being loose or for bind condition. Do not road test until condition is corrected.
(8) If components inspected look OK, road test the vehicle.
ROAD TESTING
(1) If amber warning light is illuminated, problem is with antilock system component. Refer to Antilock
Brake System Diagnosis.
5 - 8 BRAKES
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(2) If red warning light is illuminated, or if neither warning light is illuminated, make several stops and note pedal action and brake response.
(3) Check brake pedal response with transmission in Neutral and engine running. Pedal should remain firm under steady foot pressure. If pedal falls away, problem is either in vacuum booster or master cylinder.
(4) During road test, make normal and firm brake stops in 25-40 mph range. Note faulty brake operation such as pull, grab, drag, noise, fade, pedal pulsation, etc.
(5) Inspect suspect brake components and refer to problem diagnosis information for causes of various brake conditions.
COMPONENT INSPECTION
Fluid leak points and dragging brake units can usually be located without removing any components. The area around a leak point will be wet with fluid. The components at a dragging brake unit
(wheel, tire, rotor) will be quite warm or hot to the touch.
Other brake problem conditions will require component removal for proper inspection. Raise the vehicle and remove the necessary wheels for better visual access.
During component inspection, pay particular attention to heavily rusted/corroded brake components
(e.g. rotors, caliper pistons, brake return/holddown springs, support plates, etc.).
Heavy accumulations of rust may be covering severe damage to a brake component. It is wise to remove surface rust in order to accurately determine the depth of rust penetration and damage. Light surface rust is fairly normal and not a major concern (as long as it is removed). However, heavy rust buildup, especially on high mileage vehicles may cover structural damage to such important components as brakelines, rotors, support plates, and brake boosters.
Refer to the wheel brake service procedures in this group for more information.
DIAGNOSING SERVICE BRAKE PROBLEMS
BRAKE WARNING LIGHT OPERATION
The red brake warning light will illuminate under the following conditions:
• for 2-3 seconds at startup as part of normal bulb check
• parking brakes applied
• low pedal caused by malfunction in front/rear brake hydraulic circuit (differential switch valve actuated)
If the red light remains on after startup, first verify that the parking brakes are fully released. Then check pedal action and fluid level. A red light indicates that the valve in the differential pressure switch has been actuated. If a problem is confirmed, inspect the hydraulic system and wheel brake components.
On models with ABS brakes, the amber warning light only illuminates when an ABS component has malfunctioned. The ABS light operates independently of the red warning light. Refer to the antilock brake section for more detailed diagnosis information.
PEDAL FALLS AWAY
A brake pedal that falls away under steady foot pressure is generally the result of a system leak. The leak point could be at a brakeline, fitting, hose, wheel cylinder, or caliper. Internal leakage in the master cylinder caused by worn or damaged piston cups, may also be the problem cause.
If leakage is severe, fluid will be evident at or around the leaking component. However internal leakage in the master cylinder will not be physically evident. Refer to the cylinder test procedure in this section.
LOW PEDAL
If a low pedal is experienced, pump the pedal several times. If the pedal comes back up, worn lining and worn rotors or drums are the most likely causes.
However, if the pedal remains low and/or the warning light illuminates, the problem is in the master cylinder, wheel cylinders, or calipers.
A decrease in master cylinder fluid level may only be the result of normal lining wear. Fluid level will decrease as lining wear occurs. It is a result of the outward movement of caliper and wheel cylinder pistons to compensate for normal wear.
SPONGY PEDAL
A spongy pedal is most often caused by air in the system. However, thin drums or substandard brake lines and hoses will also cause a condition similar to a spongy pedal. The proper course of action is to bleed the system, or replace thin drums and suspect quality brake lines and hoses.
HARD PEDAL OR HIGH PEDAL EFFORT
A hard pedal or high pedal effort may be due to lining that is water soaked, contaminated, glazed, or badly worn. The power booster or check valve could also be faulty. Test the booster and valve as described in this section.
BRAKE DRAG
Brake drag occurs when the lining is in constant contact with the rotor or drum. Drag can occur at one wheel, all wheels, fronts only, or rears only. It is a product of incomplete brakeshoe release. Drag can be minor or severe enough to overheat the linings, rotors and drums.
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BRAKES 5 - 9
Brake drag also has a direct effect on fuel economy.
If undetected, minor brake drag can be misdiagnosed as an engine or transmission/torque converter problem.
Minor drag will usually cause slight surface charring of the lining. It can also generate hard spots in rotors and drums from the overheat/cool down process. In most cases, the rotors, drums, wheels and tires are quite warm to the touch after the vehicle is stopped.
Severe drag can char the brake lining all the way through. It can also distort and score rotors and drums to the point of replacement. The wheels, tires and brake components will be extremely hot. In severe cases, the lining may generate smoke as it chars from overheating.
An additional cause of drag involves the use of incorrect length caliper mounting bolts. Bolts that are too long can cause a partial apply condition. The correct caliper bolts have a shank length of 67 mm
(2.637 in.), plus or minus 0.6 mm (0.0236 in.). Refer to the Disc Brake service section for more detail on caliper bolt dimensions and identification.
Some common causes of brake drag are:
• loose or damaged wheel bearing
• seized or sticking caliper or wheel cylinder piston
• caliper binding on bushings or slide surfaces
• wrong length caliper mounting bolts (too long)
• loose caliper mounting bracket
• distorted brake drum or shoes
• rear brakeshoes binding on worn/damaged support plates
• severely rusted/corroded components
• misassembled components.
If brake drag occurs at all wheels, the problem may be related to a blocked master cylinder compensator port or faulty power booster (binds-does not release).
The brakelight switch can also be a cause of drag.
An improperly mounted or adjusted brakelight switch can prevent full brake pedal return. The result will be the same as if the master cylinder compensator ports are blocked. The brakes would be partially applied causing drag.
BRAKE FADE
Brake fade is a product of overheating caused by brake drag. However, overheating and subsequent fade can also be caused by riding the brake pedal, making repeated high deceleration stops in a short time span, or constant braking on steep roads. Refer to the Brake Drag information in this section for causes.
PEDAL PULSATION
Pedal pulsation is caused by components that are loose, or beyond tolerance limits.
Disc brake rotors with excessive lateral runout or thickness variation, or out of round brake drums are the primary causes of pulsation. Other causes are loose wheel bearings or calipers and worn, damaged tires.
PULL
A front pull condition could be the result of:
• contaminated lining in one caliper
• seized caliper piston
• binding caliper
• wrong caliper mounting bolts (too long)
• loose caliper
• loose or corroded mounting bolts
• improper brakeshoes
• damaged rotor
• incorrect wheel bearing adjustment (at one wheel)
A worn, damaged wheel bearing or suspension component are further causes of pull. A damaged front tire (bruised, ply separation) can also cause pull. Wrong caliper bolts (too long) will cause a partial apply condition and pull if only one caliper is involved.
A common and frequently misdiagnosed pull condition is where direction of pull changes after a few stops. The cause is a combination of brake drag followed by fade at the dragging brake unit.
As the dragging brake overheats, efficiency is so reduced that fade occurs. If the opposite brake unit is still functioning normally, its braking effect is magnified. This causes pull to switch direction in favor of the brake unit that is functioning normally.
When diagnosing a change in pull condition, remember that pull will return to the original direction if the dragging brake unit is allowed to cool down
(and is not seriously damaged).
REAR BRAKE GRAB
Rear grab (or pull) is usually caused by contaminated lining, bent or binding shoes and support plates, or improperly assembled components. This is particularly true when only one rear wheel is involved. However, when both rear wheels are affected, the master cylinder or proportioning valve could be at fault.
BRAKES DO NOT HOLD AFTER DRIVING
THROUGH DEEP WATER PUDDLES
This condition is generally caused by water soaked lining. If the lining is only wet, it can be dried by driving with the brakes lightly applied for a mile or two. However, if the lining is both wet and dirty, disassembly and cleaning will be necessary.
BRAKE FLUID CONTAMINATION
There are two basic causes of brake fluid contamination. The first involves allowing dirt, debris, or other liquid materials to enter the cylinder reservoirs
5 - 10 BRAKES
J when the cover is off. The second involves adding to, or filling the cylinder reservoirs with a non-recommended fluid.
Brake fluid contaminated with only dirt, or debris usually retains a normal appearance. In some cases, the foreign material will remain suspended in the fluid and be visible. The fluid and foreign material can be removed from the reservoir with a suction gun but only if the brakes have not been applied. If the brakes are applied after contamination, system flushing will be required. The master cylinder may also have to be disassembled, cleaned and the piston seals replaced. Foreign material lodged in the reservoir compensator/return ports can cause brake drag by restricting fluid return after brake application.
Brake fluid contaminated by a non-recommended fluid will usually be discolored, milky, oily looking, or foamy. In some cases, it may even appear as if the fluid contains sludge. However, remember that brake fluid will darken in time and occasionally be cloudy in appearance. These are normal conditions and should not be mistaken for contamination.
If some type of oil has been added to the system, the fluid will separate into distinct layers. To verify this, drain off a sample with a clean suction gun.
Then pour the sample into a glass container and observe fluid action. If the fluid separates into distinct layers, it is definitely contaminated.
The only real correction for contamination by nonrecommended fluid is to flush the entire hydraulic system and replace all the seals.
BRAKE NOISE
Chatter/Shudder
Brake chatter, or shudder is usually caused by loose or worn components, or glazed/burnt lining. Rotors with hard spots can also contribute to chatter.
Additional causes of chatter are out of tolerance rotors, brake lining not securely attached to the shoes, loose wheel bearings and contaminated brake lining.
BRAKELINING CONTAMINATION
Brakelining contamination is usually a product of leaking calipers or wheel cylinders, driving through deep water puddles, or lining that has become covered with grease and grit during repair.
WHEEL AND TIRE PROBLEMS
Some conditions attributed to brake components may actually be caused by a wheel or tire problem.
A damaged wheel can cause shudder, vibration and pull. A worn or damaged tire can also cause pull.
Severely worn tires with very little tread left can produce a condition similar to grab as the tire loses and recovers traction.
Flat-spotted tires can cause vibration and wheel tramp and generate shudder during brake operation.
A tire with internal damage such as a severe bruise or ply separation can cause pull and vibration.
DIAGNOSING PARKING BRAKE PROBLEMS
Adjustment Mechanism
Parking brake adjustment is controlled by a cable tensioner mechanism. This applies to 1991 through 1994 YJ models and 1992 and later XJ models. The cable tensioner, once adjusted at the factory, will not need further adjustment under normal circumstances. There are only two instances when adjustment is required. The first is when a new tensioner, or cables have been installed. And the second, is when the tensioner and cables are disconnected for access to other brake components.
Squeak/Squeal
Brake squeak or squeal may be due to linings that are wet or contaminated with brake fluid, grease, or oil. Glazed linings and rotors with hard spots can also contribute to squeak. Dirt and foreign material embedded in the brake lining will also cause squeak/ squeal.
A very loud squeak or squeal is frequently a sign of severely worn brake lining. If the lining has worn through to the brakeshoes in spots, metal-to-metal contact occurs. If the condition is allowed to continue, rotors can become so scored that replacement is necessary.
Thump/Clunk
Thumping or clunk noises during braking are frequently not caused by brake components. In many cases, such noises are caused by loose or damaged steering, suspension, or engine components. However, calipers that bind on the slide surfaces can generate a thump or clunk noise. In addition, worn out, improperly adjusted, or improperly assembled rear brakeshoes can also produce a thump noise.
Parking Brake problem Causes
In most cases, the actual cause of an improperly functioning parking brake (too loose/too tight/wont hold), can be traced to a drum brake component.
The leading cause of improper parking brake operation, is excessive clearance between the brakeshoes and the drum surface. Excessive clearance is a result of: lining and/or drum wear; oversize drums; or inoperative shoe adjuster components.
Excessive parking brake lever travel (sometimes described as a loose lever or too loose condition), is the result of worn brakeshoes/drums, improper brakeshoe adjustment, or mis-assembled brake parts.
A ‘‘too loose’’ condition can also be caused by inoperative brakeshoe adjusters. If the adjusters are mis-
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BRAKES 5 - 11
assembled, they will not function. In addition, since the adjuster mechanism only works during reverse stops, it is important that complete stops be made.
The adjuster mechanism does not operate when rolling stops are made in reverse. The vehicle must be brought to a complete halt before the adjuster lever will turn the adjuster screw.
A condition where the parking brakes do not hold, will most probably be due to a wheel brake component.
Items to look for when diagnosing a parking brake problem, are:
• rear brakeshoe wear
• rear brakedrum wear
• brakedrums machined beyond allowable diameter
(oversize)
• parking brake front cable not secured to lever
• parking brake rear cable seized
• parking brake strut reversed
• parking brake strut not seated in both shoes
• parking brake lever not seated in secondary shoe
• parking brake lever or brakeshoe bind on support plate
• brakeshoes reversed
• adjuster screws seized
• adjuster screws reversed
• holddown or return springs misassembled or lack tension
• wheel cylinder pistons seized
Brake drums that are machined oversize are difficult to identify. If oversize drums are suspected, the diameter of the braking surface will have to be checked with an accurate drum gauge. Oversize drums will cause low brake pedal and lack of parking brake holding ability.
Improper parking brake strut and lever installation will result in unsatisfactory parking brake operation. Intermixing the adjuster screws will cause drag, bind and pull along with poor parking brake operation.
Parking brake adjustment and parts replacement procedures are described in the Parking Brake section.
MASTER CYLINDER/POWER BOOSTER TEST
(1) Start engine and check booster vacuum hose connections. Hissing noise indicates vacuum leak.
Correct any vacuum leak before proceeding.
(2) Stop engine and shift transmission into Neutral.
(3) Pump brake pedal until all vacuum reserve in booster is depleted.
(4) Press and hold brake pedal under light foot pressure.
(a) If pedal holds firm, proceed to step (5).
(b) If pedal does not hold firm and falls away, master cylinder is faulty (internal leakage). Overhaul or replace cylinder.
(5) Start engine and note pedal action.
(a) If pedal falls away slightly under light foot pressure then holds firm, proceed to step (6).
(b) If no pedal action is discernible, power booster or vacuum check valve is faulty. Install known good check valve and repeat steps (2) through (5).
(6) Rebuild booster vacuum reserve as follows: Release brake pedal. Increase engine speed to 1500 rpm, close throttle and immediately turn off ignition.
(7) Wait a minimum of 90 seconds and try brake action again. Booster should provide two or more vacuum assisted pedal applications. If vacuum assist is not provided, perform booster and check valve vacuum tests.
POWER BOOSTER CHECK VALVE TEST
(1) Disconnect vacuum hose from check valve.
(2) Remove check valve and valve seal from booster (Fig. 1).
(3) Hand operated vacuum pump can be used for test (Fig. 2).
(4) Apply 15-20 inches vacuum at large end of check valve (Fig. 1).
(5) Vacuum should hold steady. If gauge on pump indicates any vacuum loss, valve is faulty and must be replaced.
Fig. 1 Vacuum Check Valve And Seal (Typical)
Fig. 2 Hand Operated Vacuum Pump (Typical)
5 - 12 BRAKES
POWER BOOSTER VACUUM TEST
(1) Connect a vacuum gauge to the booster check valve with a short length of hose and T-fitting (Fig.
3).
(2) Start and run engine at idle speed for one minute.
(3) Clamp hose shut between vacuum source and check valve (Fig. 3).
(4) Stop engine and observe vacuum gauge.
(5) If vacuum drops more than one inch HG (33 millibars) within 15 seconds, booster diaphragm or check valve is faulty.
Fig. 3 Booster Vacuum Test Connections
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BRAKES 5 - 13
BRAKE BLEEDING—BRAKE FLUID AND LEVEL—BRAKELINES AND HOSES
INDEX
page
Brake Bleeding—XJ/YJ with ABS Brakes
Brake Bleeding—XJ/YJ with Standard Brakes
Brake Fluid Contamination
. . . . . . . . . . . . . . . . . . 13
Brake Fluid Level
. . . . . . . . . . . . . . . . . . . . . . . . 13
page
Brakeline Charts
. . . . . . . . . . . . . . . . . . . . . . . . . 15
Brakelines and Hoses
. . . . . . . . . . . . . . . . . . . . . 15
Combination Valve
. . . . . . . . . . . . . . . . . . . . . . . 15
Recommended Brake Fluid
. . . . . . . . . . . . . . . . . 13
RECOMMENDED BRAKE FLUID
The only brake fluid recommended for Jeep vehicles with standard or antilock brakes, is Mopar brake fluid, or an equivalent fluid meeting SAE J1703 and
DOT 3 standards.
Use new brake fluid only to top off the master cylinder or refill the system. Never use reclaimed fluid, fluid not meeting the SAE/DOT standards or fluid from an unsealed container.
Do not use fluid from any container that has been left open for any length of time. Fluid in open containers can absorb moisture.
BRAKE FLUID LEVEL
Always clean the master cylinder and cover before checking fluid level. If not cleaned, dirt from the cover could enter the fluid. Also check the cover seal and replace it if torn or distorted.
Correct fluid level is to within 6 mm (1/4 in.) of the reservoir rim, or to the fill mark on models with a plastic reservoir. Refer to the Antilock Brake section for fluid levels on models equipped with ABS brakes.
BRAKE FLUID CONTAMINATION
Oil in the fluid will cause brake system rubber seals to soften and swell. The seals may also become porous and begin to deteriorate.
If fluid contamination is suspected, drain off a sample from the master cylinder. A suction gun or similar device can be used for this purpose.
Empty the drained fluid into a glass container.
Contaminants in the fluid will cause the fluid to separate into distinct layers. If contamination has occurred, the system rubber seals, hoses and cups must be replaced and the system thoroughly flushed with clean brake fluid.
BRAKE BLEEDING—XJ/YJ WITH STANDARD
BRAKES
Use Mopar DOT 3 brake fluid, or an equivalent meeting SAE/DOT standards J1703-F and DOT 3, to fill and bleed the system.
On standard brake models, bleeding can be performed either manually or with pressure equipment.
However, if pressure equipment is used, it will be necessary to hold the front brake metering valve open in order to bleed the front brakes. The valve can be held open with a tension clip tool or by hand.
It will also be necessary that a suitable size pressure tank hose adapter be available for use on the master cylinder.
MANUAL BLEEDING PROCEDURE
(1) If master cylinder has been overhauled or a new cylinder will be installed, bleed cylinder on bench before installation. This shortens time needed to bleed system and ensures proper cylinder operation.
(2) Wipe master cylinder reservoir and cap clean with shop towels.
(3) Remove cover and fill master cylinder reservoir with Mopar, or equivalent DOT 3 brake fluid.
(4) Open all caliper and wheel cylinder bleed screws.
(5) Close bleed screws after fluid begins flowing from each bleed screw.
(6) Top off master cylinder reservoir again.
(7) Use following bleed sequence:
• master cylinder
• right rear
• left rear
• right front
• left front
(8) Observe following brake bleeding precautions:
• Do not pump brake pedal at any time while bleeding. Air in system will be compressed into small bubbles that are distributed throughout hydraulic system. This will make a second and third bleeding operation necessary.
• Bleed only one wheel brake unit at a time and use a bleed hose to bleed each wheel brake unit (Fig. 7).
• Attach one end of bleed hose to bleed screw and insert opposite end in glass container partially filled with brake fluid (Fig. 7). Glass container makes it easier to see air bubbles as they exit the bleed hose.
• Be sure end of bleed hose is immersed in fluid. Immersing hose end in fluid prevents air from being drawn back into cylinder and brakeline.
(9) Bleed master cylinder first. Have helper operate brake pedal while bleeding each master cylinder fluid outlet line.
5 - 14 BRAKES
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CAUTION: Do not allow the master cylinder to run out of fluid when bleeding the brakes. An empty cylinder will allow additional air to be drawn into the system. Check the cylinder fluid level frequently and add fluid as needed.
Fig. 7 Typical Bleed Hose And Fluid Container
(10) Bleed each wheel brake unit as follows:
(a) Open caliper or wheel cylinder bleed fitting
1/2 to 3/4 turn.
(b) Have helper press and hold brake pedal to floor. Do not pump brake pedal while bleeding.
Air in system will be compressed into small bubbles that are distributed throughout hydraulic system. This will make a second and third bleeding operation necessary.
(c) Tighten bleed fitting and have helper release brake pedal. Continue bleeding operation until fluid entering bleed container is clear and free of bubbles.
(d) Repeat bleeding operation at remaining wheel brake units.
(e) Discard fluid bled into glass container. It should not be reused.
(11) Check and adjust master cylinder fluid level.
(12) Verify proper brake operation before moving vehicle.
PRESSURE BLEEDING
The front brake metering valve is located in the forward end of the combination valve. The valve stem is accessible from the same end of the valve.
The stem must be either pressed inward, or held outward slightly in order to bleed the front brakes.
(1) Fill bleeder tank if necessary.
(2) Purge air from bleeder tank and lines before proceeding.
(3) Wipe master cylinder cover clean.
(4) Remove master cylinder cover and install pressure hose adapter in place of cover. A suitable adapter will usually be available from tank manufacturer.
(5) Connect bleeder tank pressure hose to adapter.
(6) Bleed master cylinder first. Then bleed rear brakes as described in manual bleeding procedure.
(7) Bleed front brakes as described in manual bleeding procedure. Have helper hold metering valve open by pressing valve stem inward slightly. Amount of valve stem movement needed to hold valve open is quite modest. Do not use excessive force.
(8) Remove pressure bleeding equipment and top off master cylinder reservoir.
BRAKE BLEEDING—XJ/YJ WITH ABS BRAKES
A different bleeding method is required for the
ABS system. It is basically a three step process consisting of: A conventional manual brake bleed. A second bleed using the DRB II, followed by a repeat of the conventional manual bleed procedure. Recommended ABS bleeding procedure is as follows:
(1) Clean master cylinder reservoir caps and reservoir exterior. Dirt, foreign material on the caps and reservoir must not be allowed to enter reservoir.
(2) Fill reservoir with Mopar brake fluid, or equivalent quality fluid meeting SAE 1703 and DOT 3 standards.
(3) Recommended bleeding sequence is:
• master cylinder
• HCU valve body (at fluid lines)
• right rear wheel
• left rear wheel
• right front wheel
• left front wheel.
(4) Attach bleed hose to caliper or wheel cylinder bleed fitting. Immerse end of bleed hose in glass container partially filled with brake fluid. Be sure hose end is submerged in fluid (Fig. 7).
(5) Bleed each wheel brake unit as follows:
(a) Have helper apply and hold brake pedal.
(b) Open bleed screw 1/2 turn. Close bleed screw when brake pedal contacts floorpan. Do not pump brake pedal at any time while bleeding. This compresses air into small bubbles which are distributed throughout system.
Additional bleeding operations will then be necessary to remove all trapped air from the system.
(c) Repeat bleeding operation 5-7 more times at each rear wheel brake unit.
(d) Continue bleeding until fluid entering glass container is free of air bubbles. Check reservoir fluid level frequently and add fluid if necessary.
(e) Repeat bleeding procedures at front wheels.
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BRAKES 5 - 15
CAUTION: Do not allow the master cylinder reservoir to run dry while bleeding the brakes. Running dry will allow air to re-enter the system making a second bleeding operation necessary.
(6) Perform ‘‘Bleed Brake’’ procedure with DRB II scan tool. Procedure is described in DRB II software information and diagnostic manual.
(a) Connect DRB II scan tool to diagnostic connector.
(b) Run Bleed Brake procedure as described in tester manual.
(7) Repeat conventional bleeding procedure outlined in steps (1) through (8).
(8) Top off master cylinder fluid level if necessary.
(9) Verify proper brake operation.
BRAKELINES AND HOSES
Metal brakelines and rubber brake hoses should be inspected periodically and replaced if damaged.
Rubber brake hoses should be replaced if cut, cracked, swollen, or leaking. Rubber hoses must be replaced. They are not repairable parts.
When installing new, or original brakelines and hoses, lubricate the fitting threads with brake fluid before connection.
The steel brakelines should be checked every time the vehicle is in for normal maintainence. This is important on high mileage vehicles. It is even more important when a vehicle is operated in areas where salt is used regularly on the road surface during winter.
Heavily rusted/corroded brake rotors, drums, support plates, and brakelines should be cleaned and carefully inspected. Heavy rust buildup can hide severe damge to a component. Severely rusted parts should be replaced if you are unsure about their condition.
COMBINATION VALVE
The combination valve is not a serviceable part.
The valve must be replaced if a malfunction occurs.
BRAKELINE CHARTS
Brakeline charts are provided in illustration Figures 1 through 8. The illustrations show typical brakeline routing, hose connections and component position.
Fig. 1 Front Brakeline Routing (XJ With ABS Brakes)
5 - 16 BRAKES
Fig. 2 Front Brakeline Routing (YJ With ABS Brakes)
Fig. 3 Brakeline Routing (YJ With Standard Brakes)
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Fig. 4 Rear Brakeline Routing (XJ With Standard Brakes)
BRAKES 5 - 17
Fig. 5 Rear Brakeline Routing (XJ With ABS Brakes)
5 - 18 BRAKES
Fig. 6 Rear Brakeline Routing (YJ With ABS Brakes)
Fig. 7 Front Brakeline Routing (Right Hand Drive XJ With ABS Brakes)
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BRAKES 5 - 19
Fig. 8 Front Brake Hose Attachment (Right Hand Drive XJ With ABS Brakes)
5 - 20 BRAKES
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STANDARD MASTER CYLINDER
INDEX
page
General Service Information
. . . . . . . . . . . . . . . . 20
Master Cylinder Installation
. . . . . . . . . . . . . . . . . 20
page
Master Cylinder Overhaul
. . . . . . . . . . . . . . . . . . 20
Master Cylinder Removal
. . . . . . . . . . . . . . . . . . 20
GENERAL SERVICE INFORMATION
The service information in this section covers the standard (non-ABS) master cylinder only. The center feed master cylinder used with the ABS system is covered in the antilock brake component service section.
MASTER CYLINDER REMOVAL
(1) Disconnect brake lines at master cylinder.
(2) Remove cylinder mounting nuts and remove master cylinder.
(3) Remove cylinder cover and drain fluid.
MASTER CYLINDER INSTALLATION
(1) Bleed master cylinder on bench before installation. Refer to overhaul assembly procedure in this section for bleeding method.
(2) Install cylinder on brake booster studs and install cylinder attaching nuts. Tighten nuts to 21 N I m
(15 ft. lbs.).
(3) Connect brakelines to cylinder.
(4) Fill and bleed brake system.
MASTER CYLINDER OVERHAUL
CYLINDER DISASSEMBLY
(1) Remove cylinder cover and drain fluid.
(2) Examine cylinder cover seal. Discard seal if torn or distorted.
(3) Clamp cylinder in vise (Fig. 1).
(4) Press primary piston inward with wood dowel or phillips screwdriver and remove snap ring (Fig. 2).
(5) Remove and discard primary piston (Fig. 3).
Piston is serviced only as an assembly.
(6) Remove secondary piston (Fig. 4). Apply air pressure through rear outlet port to ease piston out of bore. Cover small ports at bottom of rear reservoir with towel to prevent air leakage.
(7) Discard secondary piston. Do not disassemble piston as components are only serviced as assembly.
CLEANING AND INSPECTION
Clean the cylinder with Mopar brake cleaning solvent or clean brake fluid. Remove cleaning residue with compressed air.
Inspect the cylinder bore. A light discoloration of the bore surface is normal and acceptable but only if the surface is in good condition.
Fig. 1 Cylinder Mounted In Vise
Fig. 2 Removing/Installing Piston Snap Ring
Replace the cylinder if the bore is scored, corroded, or pitted. Do not hone the cylinder bore in an at- tempt to restore the surface. Replace the cylinder if the bore is corroded or if doubt exists about cylinder bore condition.
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BRAKES 5 - 21
Fig. 3 Removing/Installing Primary Piston Fig. 5 Installing Secondary Piston brake fluid. Tubes can be fabricated from copper tubing and spare brakeline fittings.
(7) Using push rod or wooden dowel (Fig. 6), press pistons fully into bore and allow pistons to return under spring pressure. Repeat this operation until air bubbles cease to appear in fluid.
(8) Remove bleed tubes. Cap outlet ports and install reservoir cover and seal.
Fig. 4 Removing Secondary Piston Assembly
Check the outer and inner surfaces of the cylinder for cracks or porosity, especially if wet spots were noted on the cylinder outer surface during removal and disassembly.
Inspect the cylinder cover, seal and retainer spring.
Replace the seal if torn or distorted and replace the cover and spring if either part is bent or damaged in any way.
MASTER CYLINDER ASSEMBLY
(1) Coat cylinder bore and new piston assemblies with brake fluid.
(2) Install secondary piston in bore with push and turn motion (Fig. 5). Do not use any tools to start seals into bore. Tools can cut seal and scratch bore.
(3) Insert primary piston in bore (Fig. 3).
(4) Push primary piston inward and install snap ring (Fig. 2).
(5) Fill master cylinder reservoirs with brake fluid.
(6) Fabricate and install bleed tubes in master cylinder (Fig. 6). Be sure tube ends are submerged in
Fig. 6 Master Cylinder Bleeding
5 - 22 BRAKES
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POWER BRAKE BOOSTER
INDEX
page
Power Brake Booster Installation
Power Brake Booster Operation
page
Power Brake Booster Removal
. . . . . . . . . . . . . . 22
Service Information
. . . . . . . . . . . . . . . . . . . . . . . 22
SERVICE INFORMATION
The power brake booster is not a serviceable component. If a booster malfunction occurs, the booster must be replaced as an assembly. The booster (Figs.
1 and 2), is attached to the dash panel and pedal support.
Fig. 1 Power Brake Booster (XJ)
Fig. 2 Power Brake Booster (YJ)
POWER BRAKE BOOSTER OPERATION
Booster Components
The booster assembly consists of a housing divided into separate chambers by an internal diaphragm.
The outer edge of the diaphragm is attached to the booster housing. The diaphragm is in turn, connected to the booster push rod.
Two push rods are used to operate the booster. One push rod connects the booster to the brake pedal. The second push rod (at the forward end of the housing), strokes the master cylinder pistons. The rear push rod is connected to the two diaphragms in the booster housing.
The atmospheric inlet valve is opened and closed by the push rod connected to the brake pedal. The booster vacuum supply is through a hose attached to a fitting on the intake manifold. The hose is connected to a vacuum check valve in the booster housing. The check valve is a one-way device that prevents vacuum leak back.
How Brake Boost Is Generated
Power assist is generated by utilizing the pressure differential between normal atmospheric pressure and a vacuum. The vacuum needed for booster operation is taken directly from the engine intake manifold. The entry point for atmospheric pressure is through an inlet valve at the rear of the housing.
The forward portion of the booster housing (area in front of the two diaphragms), is exposed to manifold vacuum. The rear portion (area behind the diaphragms), is exposed to normal atmospheric pressure of 101.3 kilopascals (14.7 pounds/square in.).
Pressing the brake pedal causes the rear push rod to open the inlet valve. This exposes the area behind the diaphragm to atmospheric pressure. The resulting force applied to the diaphragm is what provides the extra apply pressure for power assist.
POWER BRAKE BOOSTER REMOVAL
(1) Loosen but do not remove nuts attaching master cylinder to booster (Fig. 3).
(2) Remove instrument panel lower trim cover.
(3) Remove retaining clip attaching booster push rod to brake pedal (Fig. 4).
(4) Remove bolts/nuts attaching booster to dash panel.
(5) In engine compartment, loosen vacuum hose clamp and disconnect vacuum hose from booster check valve (Fig. 5).
(6) Remove master cylinder attaching nuts and remove cylinder from mounting studs on booster.
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BRAKES 5 - 23
Fig. 3 Master Cylinder Attachment (Typical)
Fig. 4 Booster Push Rod Attachment
Fig. 5 Booster Check Valve And Hose
(7) Carefully move master cylinder aside and remove booster.
POWER BRAKE BOOSTER INSTALLATION
(1) Install check valve and grommet in booster.
Also install spacer on booster, if equipped.
(2) Position booster on dash panel and install booster mounting bolts/nuts.
(3) Working inside vehicle, install nuts on booster mounting studs.
(4) Attach booster push rod to brake pedal. Secure push rod with new bolt and nuts.
(5) Tighten booster mounting bolts/stud nuts to 41
N z m (30 ft. lbs.) on XJ and 34 N z m (25 ft. lbs.) on YJ.
(6) Tighten pedal push rod bolt inner nut to 34
N z m (25 ft. lbs.) torque. Then tighten outer locknut to
8 N z m (75 in. lbs.) torque.
(7) Install master cylinder on booster studs.
Tighten attaching nuts to 21 N z m (15 ft. lbs.).
(8) Connect vacuum hose to booster, top off master cylinder fluid level and check brake operation.
5 - 24 BRAKES
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DISC BRAKES
INDEX
page
Caliper Assembly
. . . . . . . . . . . . . . . . . . . . . . . . 29
Caliper Cleaning and Inspection
Caliper Disassembly
. . . . . . . . . . . . . . . . . . . . . . 27
Caliper Installation
. . . . . . . . . . . . . . . . . . . . . . . . 30
Caliper Operation and Wear Compensation
Caliper Removal
. . . . . . . . . . . . . . . . . . . . . . . . . 27
Disc Brake Rotor Refinishing
. . . . . . . . . . . . . . . . 32
Disc Brake Rotor Runout
. . . . . . . . . . . . . . . . . . . 31
page
Disc Brake Rotor Thickness
. . . . . . . . . . . . . . . . 31
Disc Brake Rotor Thickness Variation
Disc Brakeshoe Installation
. . . . . . . . . . . . . . . . . 26
Disc Brakeshoe Removal
. . . . . . . . . . . . . . . . . . 25
General Information
. . . . . . . . . . . . . . . . . . . . . . . 24
Rotor Installation
. . . . . . . . . . . . . . . . . . . . . . . . . 30
Rotor Removal
. . . . . . . . . . . . . . . . . . . . . . . . . . 30
Wheel Nut Tightening
. . . . . . . . . . . . . . . . . . . . . 32
GENERAL INFORMATION
1994 Jeep XJ/YJ models are equipped with single piston, floating-type disc brake calipers. Ventilated, cast rotors are used for all applications.
The disc brake calipers are supported in mounting arms that are an integral part of the steering knuckle. The calipers slide on mounting bolts that also attach the calipers to the steering knuckle.
CALIPER OPERATION AND WEAR COMPENSATION
Caliper Operation
The significant feature of single piston caliper operation is that the calipers are free to slide laterally on the mounting bolts. It is the freedom of lateral movement that allows continous compensation for lining wear.
A simplified cross section of a single piston caliper is shown in Figure 1. The illustration graphically portrays the forces at work when the brakes are applied.
Upon brake application, fluid pressure exerted against the caliper piston increases greatly. Of equal importance, is the fact that this fluid pressure is exerted equally and in all directions. What this means, is that pressure in the caliper bore, will be exactly the same as pressure on the piston. In other words, pressure against piston and caliper bore will be equal.
Fluid pressure applied to the piston is transmitted directly to the inboard brakeshoe. This forces the shoe lining against the inner surface of the disc brake rotor (Fig. 1).
At the same time, fluid pressure within the piston bore, forces the caliper to slide inward on the mounting bolts. This action brings the outboard brakeshoe lining into contact with the outer surface of the disc brake rotor (Fig. 1).
In summary, fluid pressure acting simultaneously on both piston and caliper, produces a strong clamping action. When sufficient force is applied, friction will stop the rotors from turning and bring the vehicle to a stop.
Fig. 1 Disc Brake Caliper Operation
Brakeshoe Wear Compensation
Application and release of the brake pedal generates only a very slight movement of the caliper and piston. Upon release of the pedal, the caliper and piston return to a rest position. The brakeshoes do not retract an appreciable distance from the rotor. In fact, clearance is usually at, or close to zero. The reasons for this are to keep road debris from getting between the rotor and lining and in wiping the rotor surface clear each revolution.
The caliper piston seal controls the amount of piston extension needed to compensate for normal lining wear.
During brake application, the seal is deflected outward by fluid pressure and piston movement (Fig. 2).
When the brakes (and fluid pressure) are released, the seal relaxes and retracts the piston.
The amount of piston retraction is determined by brakelining wear. Generally, the amount is just
J enough to maintain contact between the piston and inboard brakeshoe. Brakelining running clearance at the rotor, will be held between zero and a maximum of 0.12 mm (0.005 in.).
BRAKES 5 - 25
Fig. 2 Lining Wear Compensation By Piston Seal
DISC BRAKESHOE REMOVAL
(1) Raise vehicle and remove front wheels.
(2) Drain small amount of fluid from master cylinder front brake reservoir with suction gun.
(3) Bottom caliper piston in bore with C-clamp. Position clamp screw on outboard brakeshoe and clamp frame on rear of caliper. Typical C-clamp attachment is shown in Figure 3. Do not allow clamp screw to bear directly on outboard shoe retainer spring.
Use wood or metal spacer between shoe and clamp screw if necessary.
Fig. 4 Removing/Installing Caliper Mounting Bolts
Fig. 5 Tilting Caliper Outward
Fig. 3 Bottoming Caliper Piston With C-Clamp
(4) Remove caliper mounting bolts (Fig. 4). If brakeshoes are being removed to correct a pull or drag condition, verify length of caliper bolts as they may be incorrect length. Refer to bolt information in brakeshoe installation procedure.
(5) Tilt top of caliper outward. Use pry tool if necessary (Fig. 5).
(6) Lift caliper off steering knuckle (Fig. 6).
(7) If original brakeshoes will be used, keep them in sets (left and right); they are not interchangeable.
Fig. 6 Caliper Removal
(8) Remove outboard shoe. Press one end of shoe inward to disengage shoe lug. Then rotate shoe upward until retainer spring clears caliper. Press opposite end of shoe inward to disengage shoe lug and rotate shoe up and out of caliper (Fig. 7).
5 - 26 BRAKES
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Fig. 7 Removing Outboard Brakeshoe
(9) Remove inboard shoe. Grasp ends of shoe and tilt shoe outward to release springs from caliper piston (Fig. 8). Then remove shoe from caliper.
Fig. 9 Caliper Dust Boots And Bushing Locations
Fig. 8 Removing Inboard Brakeshoe
(10) Support caliper on box, mechanics stool, or secure it to nearby suspension part with wire. Do not allow brake hose to support caliper weight.
(11) Wipe caliper off with shop rags or towels. Do not use compressed air. Compressed air can unseat dust boot and force dirt into piston bore.
(12) Inspect condition of caliper piston dust boot
(Fig. 9). Overhaul caliper if there is evidence of leakage past piston and dust boot. Then inspect caliper bushings and boots (Fig. 9). Replace boots if torn or cut. If bushings or boots are damaged, replace them.
DISC BRAKESHOE INSTALLATION
(1) Clean brakeshoe mounting ledge slide surfaces of steering knuckle with wire brush. Then apply light coat of Mopar multi-mileage grease to slide surfaces (Fig. 10).
(2) Lubricate caliper mounting bolts and bushings
(Fig. 10). Use GE 661 or Dow 111 silicone grease.
Fig. 10 Caliper Lubrication Points
(3) Keep new or original brakeshoes in sets. Do not interchange them.
(4) Install inboard shoe in caliper (Fig. 11). Be sure shoe retaining springs are fully seated in caliper piston.
(5) Install outboard shoe in caliper (Fig. 12). Start one end of shoe in caliper. Rotate shoe downward and into place until shoe locating lugs and shoe spring are seated.
(6) Verify that locating lugs on outboard shoe are seated in caliper (Fig. 6).
(7) Install caliper. Position notches at lower end of brakeshoes on bottom mounting ledge (Fig. 13). Then install caliper over rotor and seat upper ends of brakeshoes on top mounting ledge (Fig. 11).
CAUTION: Before securing the caliper, be sure the caliper brake hose is not twisted, kinked or touching any chassis components. Also be sure the hose is clear of all suspension and steering components.
Loosen and reposition the hose if necessary.
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BRAKES 5 - 27
Fig. 11 Installing Inboard Brakeshoe
Fig. 13 Caliper Installation
Fig. 12 Installing Outboard Brakeshoe
(8) Install and tighten caliper mounting bolts to
10-20 N z m (7-15 ft. lbs.) torque.
CAUTION: If new caliper bolts are being installed, or if the original reason for repair was a drag/pull condition, check caliper bolt length before proceeding. If the bolts have a shank length greater than
67.6 mm (2.66 in.), they will contact the inboard brakeshoe causing a partial apply condition. Refer to Figure 14 for required caliper bolt length.
(9) Install wheels. Tighten lug nuts to 102 N z m (75 ft. lbs.) torque.
(10) Pump brake pedal until caliper pistons and brakeshoes are seated.
(11) Top off brake fluid level if necessary. Use Mopar brake fluid or equivalent meeting SAE J1703 and DOT 3 standards only.
CALIPER REMOVAL
(1) Raise vehicle and remove front wheels.
(2) Remove caliper mounting bolts (Fig. 4).
Fig. 14 Caliper Mounting Bolt Dimensions
(3) Rotate caliper rearward by hand or with pry tool (Fig. 5). Then rotate caliper and brakeshoes off mounting ledges.
(4) Remove caliper hose fitting bolt and disconnect front brake hose at caliper. Discard fitting bolt washers. They are not reusable and should be replaced.
(5) Remove caliper from vehicle.
CALIPER DISASSEMBLY
(1) Remove brakeshoes from caliper.
(2) Pad interior of caliper with minimum, 2.54 cm
(1 in.) thickness of shop towels or rags (Fig. 15). Towels are needed to protect caliper piston during removal.
(3) Remove caliper piston with short bursts of low pressure compressed air. Direct air through fluid inlet port and ease piston out of bore (Fig. 16).
5 - 28 BRAKES
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Fig. 15 Padding Caliper Interior To Protect Piston
During Removal
CAUTION: Do not blow the piston out of the bore with sustained air pressure. This could result in a cracked piston. Use only enough air pressure to ease the piston out. In addition, NEVER attempt to catch the piston as it leaves the bore. This will result in personal injury.
Fig. 17 Removing Caliper Piston Dust Boot
Fig. 18 Removing Caliper Piston Seal
Fig. 16 Removing Caliper Piston
(4) Remove caliper piston dust boot (Fig. 17). Collapse boot with suitable tool and remove and discard boot.
(5) Remove and discard caliper piston seal with wood or plastic tool (Fig. 18). Do not use metal tools as they will scratch piston bore.
(6) Remove caliper mounting bolt bushings and boots (Fig. 19).
Fig. 19 Caliper Slide Bushing And Boot
CALIPER CLEANING AND INSPECTION
Clean the caliper and piston with Mopar brake cleaner, clean brake fluid, or denatured alcohol only.
Do not use gasoline, kerosene, thinner, or similar solvents. These products leave a residue that will damage pistons and seals.
Wipe the caliper and piston dry with lint free towels or use low pressure compressed air.
Inspect the piston and piston bore. Replace the caliper if the bore is corroded, rusted, pitted, or scored.
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BRAKES 5 - 29
Do not hone the caliper piston bore. Replace the caliper if the bore exhibits any of the aforementioned conditions.
Inspect the caliper piston. The piston is made from a phenolic resin (plastic material) and should be smooth and clean. Replace the piston if cracked, chipped, or scored. Do not attempt to restore a scored, or corroded piston surface by sanding or polishing. The piston must be replaced if damaged.
CAUTION: Never interchange phenolic resin and steel caliper pistons. The seals, seal grooves, caliper bores and piston tolerances are different for resin and steel pistons. Do not intermix these components.
Inspect the caliper mounting bolt bushings and boots. Replace the boots if cut or torn. Clean and lubricate the bushings with GE 661 or Dow 111 silicone grease if necessary.
Inspect condition of the caliper mounting bolts. Replace the bolts if corroded, rusted, or worn. Do not reuse the bolts if unsure of their condition.
Length of the caliper mounting bolts is also extremely important.
Use the replacement bolts specified in the parts catalog at all times. Do not use substitute bolts.
Bolts that are too long will partially apply the inboard brakeshoe causing drag and pull. Refer to the caliper and brakeshoe installation procedures for service details and bolt dimensions.
CALIPER ASSEMBLY
(1) Coat caliper piston bore, new piston seal and piston with clean, fresh brake fluid.
(2) Lubricate caliper bushings and interior of bushing boots with GE 661, Dow 111, or Permatex Dielectric silicone grease.
(3) Install bushing boots in caliper first. Then insert bushing into boot and push bushing into place
(Fig. 20).
(4) Install new piston seal in caliper bore. Press seal into seal groove with finger (Fig. 21).
Fig. 21 Installing Piston Seal
(5) Install dust boot on caliper piston (Fig. 22).
Slide boot over piston and seat boot in piston groove.
(6) Start caliper piston in bore by hand (Fig. 23).
Use a turn and push motion to work piston into seal.
Once piston is started in seal, press piston only part
way into bore.
Fig. 22 Installing Dust Boot On Piston
Fig. 20 Installing Bushings And Boots
Fig. 23 Installing Caliper Piston
(7) Apply light coat of GE 661, Dow 111, or Permatex silicone grease to indicated areas (circumfer-
5 - 30 BRAKES
ence) of piston and caliper boot groove (Fig. 24).
Grease serves as corrosion protection for these areas.
(8) Press caliper piston to bottom of bore.
J
Fig. 24 Typical Caliper/Piston Areas To Be Lightly
Coated With Silicone Grease
(9) Seat dust boot in caliper with Installer Tool
C-4842 and Tool Handle C-4171 (Fig. 25).
Fig. 26 Front Brake Hose And Fitting Components
(Fig. 13). Then rotate caliper over rotor and seat notches at upper end of shoes on mounting ledge
(Fig. 13).
(4) Coat caliper mounting bolts with GE 661 or
Dow 111 silicone grease. Then install and tighten bolts to 10-20 N z m (7-15 ft. lbs.) torque.
CAUTION: If new caliper bolts are being installed, or if the original reason for repair was a drag/pull condition, check caliper bolt length before proceeding. If the bolts have a shank length greater than
67.6 mm (2.66 in.), they may contact the inboard brakeshoe causing a partial apply condition. Refer to Figure 14 for the required caliper bolt length.
(5) Position front brake hose clear of all chassis components and tighten caliper fitting bolt to 31 N z m
(23 ft. lbs.) torque.
CAUTION: Be sure the brake hose is not twisted or kinked at any point. Also be sure the hose is clear of all steering and suspension components. Loosen and reposition the hose if necessary.
(6) Install wheels. Tighten wheel lug nuts to 109-
150 N z m (80-110 ft. lbs.) torque.
(7) Fill and bleed brake system. Refer to procedures in Service Adjustments section.
Fig. 25 Seating Caliper Piston Piston Dust Boot
(10) Install caliper bleed screw if removed.
CALIPER INSTALLATION
(1) Install brakeshoes in caliper (Figs. 11, 12).
(2) Connect brake hose fitting to caliper but do not tighten fitting bolt completely at this time. Be sure to use new washers on fitting bolt to avoid leaks
(Fig. 26).
(3) Install caliper. Position mounting notches at lower end of brakeshoes on bottom mounting ledge
ROTOR REMOVAL
(1) Raise vehicle and remove wheel.
(2) Remove caliper.
(3) Remove retainers securing rotor to hub studs
(Fig. 27).
(4) Remove rotor from hub (Fig. 27).
(5) If rotor shield requires service, remove front hub and bearing assembly.
ROTOR INSTALLATION
(1) Install rotor on hub.
(2) Install caliper.
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BRAKES 5 - 31
Check lateral runout with a dial indicator (Fig.
29). Excessive lateral runout will cause brake pedal pulsation and rapid, uneven wear of the brakeshoes.
Maximum allowable rotor runout for all models is
0.12 mm (0.005 in.).
Fig. 27 Rotor And Hub
(3) Install new spring nuts on wheel studs.
(4) Install wheel and lower vehicle.
DISC BRAKE ROTOR THICKNESS
Rotor minimum usable thickness is 22.7 mm (0.89
in.). This dimension is either cast, or stamped on the rotor hub, or outer edge.
Measure rotor thickness at the center of the brakeshoe contact surface.
Replace the rotor if worn below minimum thickness. Also replace the rotor if refinishing would reduce thickness below the allowable minimum.
DISC BRAKE ROTOR RUNOUT
Check rotor lateral runout whenever pedal pulsation, or rapid, uneven brakelining wear has occurred.
On 4-wheel drive models, the rotor must be securely clamped to the hub to ensure an accurate runout measurement. Secure the rotor with the wheel nuts and 4 or 5 large diameter flat washers on each stud as shown (Fig. 28).
Use a dial indicator to check lateral runout (Fig. 28).
Maximum allowable rotor lateral runout is 0.13
mm (0.005 in.).
Fig. 29 Typical Method Of Checking Rotor Lateral
Runout
DISC BRAKE ROTOR THICKNESS VARIATION
Variations in rotor thickness will cause pedal pulsation, noise and shudder.
Measure rotor thickness at four to six points around the rotor face. Position the micrometer approximately 2 cm (3/4 in.) from the rotor outer circumference for each measurement (Fig. 30).
Thickness should not vary by more than 0.013 mm
(0.0005 in.) from point-to-point on the rotor. Refinish or replace the rotor if necessary.
Fig. 28 Securing 4 x 4 Rotor For Lateral Runout Check
Fig. 30 Measuring Rotor Thickness Variation
5 - 32 BRAKES
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DISC BRAKE ROTOR REFINISHING
When To Refinish
Rotor braking surfaces can be refinished by sanding and/or machining in a disc brake lathe. However, the rotor should be cleaned and inspected beforehand. Careful inspection will avoid refinishing rotors with very little service life left in them.
Pay particular attention to rotors that are heavily rusted, or corroded. Accumulated rust/corrosion on braking surfaces and ventilating ribs may extend to a depth beyond acceptable limits. This can be especially true on: (a) high mileage vehicles; (b) vehicles regularly exposed to road salt during winter months;
(c) vehicles operated in coastal regions where salt air/road splash is a factor; (d) and vehicles used for extensive off-road operation.
Recommended Refinishing Equipment
The brake lathe must be capable of machining both rotor surfaces simultaneously with dual cutter heads
(Fig. 31). Equipment capable of machining only one side at a time will produce a tapered rotor.
The lathe should also be equipped with a grinder attachment, or dual sanding discs for final cleanup or light refinishing.
Refinishing Techniques
If the rotor surfaces only need minor cleanup of rust, scale, or scoring, use abrasive sanding discs to clean up the rotor surfaces. However, when a rotor is scored or worn, machining with cutting tools will be required.
Light cuts are recommended when machining the rotor surfaces. Heavy feed rates are not recommended and may result in chatter marks, or taper.
CAUTION: Never refinish a rotor if machining would cause the rotor to fall below minimum allowable thickness.
The final finish on the rotor should be a non-directional, cross hatch pattern (Fig. 32). Use sanding discs to produce this finish.
Fig. 31 Rotor Refinishing Equipment
Fig. 32 Preferred Rotor Surface Finish
WHEEL NUT TIGHTENING
The wheel attaching nuts must be tightened properly to ensure efficient brake operation. Overtightening the nuts or tightening them in the wrong sequence can
J cause distortion of the brake rotors and drums.
Impact wrenches are not recommended for tightening wheel nuts. A torque wrench should be used for this purpose.
A light coat of LPS Anti-Corrosion spray lube around the hub face and on the studs will cut down on rust/corrosion formation.
The correct tightening sequence is important in avoiding rotor and drum distortion. The correct sequence is in a diagonal crossing pattern (Fig. 33).
Recommended torque range for XJ/YJ wheel lug nuts is 108-149 N z m (80-110 ft. lbs.). Preferred set-to torque is 129 N z m (95 ft. lbs.) torque.
Seat the wheel and install the wheel nuts finger tight. Tighten the nuts in the sequence to 1/2 the required torque. Then repeat the tightening sequence to final specified torque.
BRAKES
Fig. 33 Wheel Nut Tightening Sequence
5 - 33
5 - 34 BRAKES
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DRUM BRAKES
INDEX
page
Brake Drum Refinishing
. . . . . . . . . . . . . . . . . . . . 37
Drum Brake Adjustment
. . . . . . . . . . . . . . . . . . . 35
Drum Brakeshoe Installation
. . . . . . . . . . . . . . . . 34
Drum Brakeshoe Removal (Figs. 1 and 2)
Support Plate Replacement
. . . . . . . . . . . . . . . . . 37
page
Wheel Cylinder Installation
. . . . . . . . . . . . . . . . . 37
Wheel Cylinder Overhaul (Figs. 8 and 9)
Wheel Cylinder Removal
. . . . . . . . . . . . . . . . . . . 36
Wheel Nut Tightening
. . . . . . . . . . . . . . . . . . . . . 37
DRUM BRAKESHOE REMOVAL (Figs. 1 and 2)
(1) Raise vehicle and remove rear wheels.
(2) Remove and discard spring nuts securing drums to wheel studs.
(3) Remove brake drums. If drums prove difficult to remove, retract brakeshoes. Remove access plug at the rear of backing plate and back off adjuster screw with brake tool and screwdriver.
(4) Remove U-clip and washer securing adjuster cable to parking brake lever.
(5) Remove primary and secondary return springs from anchor pin with Brake Spring Plier Tool 8078.
(6) Remove holddown springs, retainers and pins with Retaining Spring Tool C-4070.
(7) Install Spring Clamps C-416 on wheel cylinders to hold pistons in place.
(8) Remove adjuster lever, adjuster screw and spring.
(9) Remove adjuster cable and cable guide.
(10) Remove brakeshoes and parking brake strut.
(11) Disconnect cable from parking brake lever and remove lever.
DRUM BRAKESHOE INSTALLATION
(1) Clean support plate with Mopar brake cleaner.
Replace support plate if worn, or rusted through at any point. Do not attempt to salvage, or reuse a damaged support plate.
(2) Clean and lubricate anchor pin with light coat of Mopar multi-mileage grease.
(3) Apply Mopar multi-mileage grease to brakeshoe contact surfaces of support plate (Figs. 3 and 4).
(4) Lubricate adjuster screw threads and pivot with Mopar spray lube.
(5) Attach parking brake lever to secondary brakeshoe. Use new washer and U-clip to secure lever.
(6) Remove wheel cylinder clamps.
(7) Attach parking brake cable to lever.
(8) Install brakeshoes on support plate. Secure shoes with new holddown springs, pins and retainers.
(9) Install parking brake strut and spring.
(10) Install guide plate and adjuster cable on anchor pin.
(11) Install primary and secondary return springs.
(12) Install adjuster cable guide on secondary shoe.
Fig. 1 Nine Inch Drum Brake Components
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BRAKES 5 - 35
Fig. 2 Ten Inch Drum Brake Components
Fig. 3 Shoe Contact Surfaces (9-Inch Support Plate)
5).
(13) Lubricate and assemble adjuster screw (Fig.
(14) Install adjuster screw, spring and lever and connect to adjuster cable.
(15) Adjust shoes to drum as described in following procedure.
(16) Install wheel/tire assemblies and lower vehicle.
(17) Verify firm brake pedal before moving vehicle.
DRUM BRAKE ADJUSTMENT
Rear drum brakes are equipped with a self adjusting mechanism. Under normal circumstances, the only time adjustment is required is when the shoes are replaced, removed for access to other parts, or when one or both drums are replaced.
Fig. 4 Shoe Contact Surfaces (10-Inch Support Plate)
The only tool needed for adjustment is a standard brake gauge.
Adjustment is performed with the brakeshoes installed on the support plate. Procedure is as follows:
ADJUSTMENT PROCEDURE
(1) Raise and support vehicle rear end and remove wheels and brake drums.
5 - 36 BRAKES
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Fig. 5 Adjuster Screw Components (9-Inch Brake)
(2) Verify that left/right automatic adjuster lever and cable are properly connected.
(3) Insert brake gauge in drum. Expand gauge until gauge inner legs contact drum braking surface.
Then lock gauge in position (Fig. 6).
Fig. 7 Adjusting Brakeshoes To Gauge
WHEEL CYLINDER REMOVAL
(1) Raise vehicle and remove wheel.
(2) Disconnect brakeline at wheel cylinder. If cyl- inder brakeline fitting is hard to break loose, spray generous amount of Mopar Rust Penetrant between fitting and line and around fitting threads in wheel cylinder. Note that it may require a few minutes for penetrant to work.
(3) Remove brakeshoes.
(4) Remove bolts attaching wheel cylinder to support plate and remove cylinder.
WHEEL CYLINDER OVERHAUL (Figs. 8 and 9)
(1) Remove links.
(2) Remove dust boots.
(3) Remove cups and pistons. Discard cups.
(4) Remove and discard spring and expander.
(5) Remove bleed screw.
Fig. 6 Adjusting Gauge To Brake Drum
(4) Reverse gauge and install it on brakeshoes
(Fig. 6). Position gauge legs at shoe centers as shown. If gauge does not fit (too loose or tight), adjust shoes.
(5) Pull shoe adjuster star wheel away from adjuster lever.
(6) Turn adjuster star wheel (by hand) to expand or retract brakeshoes. Continue adjustment until gauge outside legs are light drag-fit on shoes (Fig. 7).
(7) Repeat adjustment at opposite brakeshoe assembly.
(8) Install brake drums and wheels and lower vehicle.
(9) Make final adjustment as follows:
(a) Drive vehicle and make one forward stop followed by one reverse stop.
(b) Repeat procedure 8-10 times to actuate self adjuster components and equalize adjustment.
(c) Bring vehicle to complete standstill at each stop. Incomplete, rolling stops will NOT activate adjuster mechanism.
Fig. 8 Wheel Cylinder (9-Inch Brake)
(6) Clean cylinder, pistons and links with Mopar brake cleaner.
(7) Inspect cylinder bore and pistons. Light discoloration of bore is acceptable. However, replace cylinder if bore and pistons are scored, pitted, or corroded.
Do not hone cylinder bores or polish pistons.
Replace cylinder as an assembly if bore is damaged.
(8) Install bleed screw.
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BRAKES 5 - 37
Fig. 9 Wheel Cylinder (10-Inch Brake)
(9) Coat cylinder bore, pistons, cups and expander with brake fluid and reassemble cylinder components. Be sure piston cup lips face expander.
WHEEL CYLINDER INSTALLATION
(1) Apply small bead of silicone sealer around cylinder mounting surface of support plate.
(2) Start brakeline in wheel cylinder fitting by hand.
(3) Align and seat wheel cylinder on support plate
(Fig. 10).
(4) Install cylinder mounting bolts (Fig.
10).
Tighten bolts to 10 N z m (90 in. lbs.) torque.
Fig. 10 Wheel Cylinder Mounting
(5) Tighten brakeline fitting to 15 N z m (132 in.
lbs.) torque.
(6) Install brakeshoes. Adjust shoes to drum with brake gauge.
(7) Install brake drums and lower vehicle.
(8) Fill master cylinder and bleed brakes.
SUPPORT PLATE REPLACEMENT
The support plate should cleaned and inspected whenever the drum brake components are being serviced.
Check the support plate for wear, or rust through at the contact pads and replace the plate if necessary. Be sure to lubricate the contact pads with Mopar multi-mileage grease before shoe installation.
Lubrication will avoid noisy operation and shoe bind.
(1) Raise vehicle and remove wheel/tire assembly.
(2) Remove brake drum, brakeshoes, and wheel cylinder.
(3) Remove axle shaft as described in Group 3.
(4) Remove support plate attaching nuts and remove support plate.
(5) Clean axle tube flange. If gasket is not used on flange, apply thin bead of silicone adhesive/sealer to flange.
(6) Position new support plate on axle tube flange.
(7) Apply Mopar Lock N
9
Seal, or Loctite 242 to support plate attaching nuts. Then install and tighten nuts.
(8) Apply light coat of Mopar multi-mileage grease to contact pads of new support plate.
(9) Install wheel cylinder and brakeshoes.
(10) Adjust brakeshoes to drums. Refer to procedure in this section.
(11) Bleed brakes.
(12) Install wheel and tire assembly.
(13) Adjust parking brake cable tensioner. Refer to procedure in Parking Brake section.
(14) Lower vehicle and verify proper service brake and parking brake operation.
BRAKE DRUM REFINISHING
Brake drums can be machined to restore the braking surface. Use a brake lathe to clean up light scoring and wear.
CAUTION: Never refinish a brake drum if machining will cause the drum to exceed maximum allowable brake surface diameter.
Brake drums that are warped, distorted, or severely tapered should be replaced. Do not refinish drums exhibiting these conditions. Brake drums that are heat checked or have hard spots should also be replaced.
If the brake drums are heavily coated with rust, clean and inspect them carefully. Rust damage on high mileage drums can be severe enough to require replacement.
The maximum allowable diameter for the drum braking surface is usually indicated on the drum outer face (Fig. 11).
WHEEL NUT TIGHTENING
The wheel attaching lug nuts must be tightened properly to ensure efficient brake operation. Overtightening the nuts or tightening them in the wrong sequence can cause distortion of the brake rotors and drums.
Impact wrenches are not recommended for tightening wheel nuts. A torque wrench should be used for this purpose.
A light coat of LPS Anti-Corrosion spray lube around the hub face and on the studs will cut down on rust/corrosion formation.
5 - 38 BRAKES
Fig. 11 Typical Location Of Brake Drum Refinish
Limit
The correct tightening sequence is important in avoiding rotor and drum distortion. The correct sequence is in a diagonal crossing pattern (Fig. 12).
Recommended torque range for XJ/YJ wheel lug nuts is 109-150 N z m (80-110 ft. lbs.).
Seat the wheel and install the wheel nuts finger tight. Tighten the nuts in the sequence to half the required torque. Then repeat the tightening sequence to final specified torque.
Fig. 12 Wheel Nut Tightening Sequence
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BRAKES 5 - 39
ABS SYSTEM OPERATION
INDEX
page
Acceleration Switch
. . . . . . . . . . . . . . . . . . . . . . . 41
Combination Valve
. . . . . . . . . . . . . . . . . . . . . . . 42
Electronic Control Unit (ECU)
. . . . . . . . . . . . . . . 41
General Information
. . . . . . . . . . . . . . . . . . . . . . . 39
Hydraulic Control Unit (HCU)
. . . . . . . . . . . . . . . . 39
Ignition Switch
. . . . . . . . . . . . . . . . . . . . . . . . . . . 42
page
Master Cylinder
. . . . . . . . . . . . . . . . . . . . . . . . . . 40
Pedal Travel Sensor
. . . . . . . . . . . . . . . . . . . . . . 41
Power Brake Booster
. . . . . . . . . . . . . . . . . . . . . 40
System Relays
. . . . . . . . . . . . . . . . . . . . . . . . . . 42
System Warning Lights
. . . . . . . . . . . . . . . . . . . . 42
Wheel Speed Sensors
. . . . . . . . . . . . . . . . . . . . . 41
GENERAL INFORMATION
The Jeep antilock brake system (ABS) is an electronically operated, all-wheel brake control system.
Major components include the master cylinder, vacuum power brake booster, ECU, hydraulic control unit (HCU) and various control sensors (Fig. 1). The
ABS brake system is available on XJ and YJ models.
• hydraulic control unit (HCU)
• tandem master cylinder with central valves
• vacuum power brake booster
• pedal travel sensor
• acceleration switch
• main relay and pump motor relay
• ABS warning light
• pump motor sensor
Fig. 1 Antilock Components (XJ Shown)
The antilock hydraulic system is a three channel design. The front wheel brakes are controlled individually and the rear wheel brakes in tandem (Fig. 2).
The antilock system is designed to retard wheel lockup during periods of high wheel slip when braking. Retarding wheel lockup is accomplished by modulating fluid pressure to the wheel brake units.
The ABS electronic control system is separate from other electrical circuits in the vehicle. A specially programmed electronic control unit (ECU) is used to operate the system components.
System components include:
• electronic control unit (ECU)
• wheel speed sensors and axle shaft tone rings
Fig. 2 AntiLock System Basic Layout
HYDRAULIC CONTROL UNIT (HCU)
The hydraulic control unit (HCU) consists of a valve body and pump/motor assembly (Fig. 3).
The valve body contains the electrically operated solenoid valves. It is the solenoid valves that modulate brake fluid apply pressure during antilock braking.
The valves are operated by the antilock electronic control unit (ECU).
5 - 40 BRAKES
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Fig. 3 AntiLock Hydraulic Control Unit (HCU)
The HCU provides three channel pressure control to the front and rear brakes. One channel controls the rear wheel brakes in tandem. The two remaining channels control the front wheel brakes individually.
During antilock braking, the solenoid valves are opened and closed as needed. The valves are not static.
They are cycled rapidly and continuously to modulate pressure and control wheel slip and deceleration.
The pump/motor assembly provides the extra volume of fluid needed during antilock braking. The pump is connected to the master cylinder reservoir by supply and return hoses.
The pump is operated by an integral electric motor.
The DC type motor is controlled by the ECU.
The pump mechanism consists of two opposing pistons operated by an eccentric cam. One piston supplies the primary hydraulic circuit. The opposite piston supplies the secondary hydraulic circuit. In operation, one piston draws fluid from the master cylinder reservoir. The opposing piston then pumps fluid to the valve body solenoids. The pump cam is operated by the electric motor.
MASTER CYLINDER
A new style tandem master cylinder is used with the
ABS system (Fig. 4). It is a center feed design. The primary and secondary pistons each contain a central valve which is a unique feature. The valves are used in place of the conventional piston and seal assemblies.
The valves close and open the cylinder pressure chambers during brake application and release.
The only repairable components on the ABS master cylinder are the reservoir, reservoir grommets and the connecting hoses. The cylinder itself cannot be disassembled and is serviced only as an assembly.
POWER BRAKE BOOSTER
A dual diaphragm, vacuum operated power brake booster is used with the ABS master cylinder (Fig.
Fig. 4 ABS Power Brake Booster/Master Cylinder Assembly
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BRAKES 5 - 41
4). The engine intake manifold serves as the vacuum source for booster operation.
The booster is mounted on the engine compartment side of the dash panel. The master cylinder is mounted on attaching studs at the front of the booster. The master cylinder central valves are directly actuated by the booster push rod.
The pedal travel sensor is mounted in the forward face of the booster shell. The sensor plunger is actuated by the booster diaphragm plate.
PEDAL TRAVEL SENSOR
The pedal travel sensor signals brake pedal position to the antilock ECU. The sensor signal is based on changes in electrical resistance. The resistance changes occur in steps that are generated by changes in brake pedal position. A resistance signal generated by changing brake pedal position, will cause the
ECU to run the antilock pump when necessary.
The sensor is a plunger-type, electrical switch mounted in the forward housing of the power brake booster (Fig. 5). The sensor plunger is actuated by movement of the booster diaphragm plate.
The tip on the sensor plunger is color coded. The tip must be matched to the color dot on the face of the brake booster front shell (Fig. 5).
WHEEL SPEED SENSORS
A sensor is used at each wheel. The sensors convert wheel speed into an electrical signal. This signal is transmitted to the antilock electronic control unit (ECU).
A gear-type tone ring serves as the trigger mechanism for each sensor. The tone rings are mounted at the outboard ends of the front and rear axle shafts.
Different sensors are used at the front and rear wheels (Fig. 6). The front/rear sensors have the same electrical values but are not interchangeable.
Fig. 5 Pedal Travel Sensor Location
Fig. 6 Wheel Speed Sensors
ELECTRONIC CONTROL UNIT (ECU)
A separate electronic control unit (ECU) monitors, operates and controls the antilock system (Fig. 7).
The ECU contains dual microprocessors. The logic block in each microprocessor receives identical sensor signals. These signals are processed and compared simultaneously (Fig. 8).
The ECU is located under the instrument panel. It is located at the right side of the steering column.
The power up voltage source for the ECU is through the ignition switch in the On and Run positions.
The antilock ECU is separate from the other vehicle electronic control units. It contains a self check program that illuminates the amber warning light when a system fault is detected. Faults are stored in a diagnostic program memory and are accessible with the DRB II scan tool.
ABS faults remain in memory until cleared, or until after the vehicle is started approximately 50 times. Stored faults are not erased if the battery is disconnected.
ACCELERATION SWITCH
An acceleration switch (Fig. 9), provides an additional vehicle deceleration reference during 4-wheel drive operation. The switch is monitored by the antilock ECU at all times.
The switch reference signal is utilized by the ECU when all wheels are decelerating at the same speed.
Equal wheel speeds occur during braking in undifferentiated 4-wheel ranges.
5 - 42 BRAKES
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Fig. 7 Anti-Lock ECU
Fig. 8 ECU Dual Microprocessor Schematic
SYSTEM RELAYS
The ABS system has two relays, which are the main and motor pump relays. The motor pump relay is used for the motor pump only. The main relay is used for the solenoid valves and remaining system components. The main relay is connected to the ECU at the power control relay terminal.
The pump motor relay starts/stops the pump motor when signaled by the ECU. The start/stop signal to
Fig. 9 Acceleration Switch the ECU is generated by the pedal travel sensor. Refer to the ABS schematic at the end of this section for circuit details.
IGNITION SWITCH
The antilock ECU and warning light are in standby mode with the ignition switch in Off or Accessory position. No operating voltage is supplied to the system components.
A 12 volt power feed is supplied to the ECU, relays, solenoid valves, and warning light when the ignition switch is in the ON, Start and Run positions.
Refer to the ABS system schematic at the end of this section for details.
SYSTEM WARNING LIGHTS
Two warning lights are used. The standard brake system light is red. The antilock system light is amber. Both lights are in the instrument cluster. The amber ABS light is in circuit with the ECU and operates independently of the red brake light.
The amber light indicates antilock system condition. It is in circuit with the valve body solenoids and main relay.
The light illuminates (flashes) at start-up for the self check. The light then goes out when the self check program determines system operation is normal.
If an ABS fault occurs either during the start-up self check, or during normal operation, the amber light remains on until the fault is corrected.
COMBINATION VALVE
A combination valve is used with the ABS system
(Fig. 2). The valve contains a front/rear brake pressure switch and proportioning valve. The valve is connected between the master cylinder and hydraulic control unit (HCU).
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ANTILOCK BRAKE SYSTEM OPERATION 5 - 43
ANTILOCK BRAKE SYSTEM OPERATION
INDEX
page
ABS Operation in Antilock Braking Mode
ABS Operation in Normal Braking Mode
Acceleration Switch Operation
. . . . . . . . . . . . . . . 45
ECY Operation
. . . . . . . . . . . . . . . . . . . . . . . . . . 46
page
HCU Pump and Pedal Travel Sensor Operation
HCU Solenoid Valve Operation
. . . . . . . . . . . . . . 43
System Power-Up and Initialization
Wheel Speed Sensor Operation
SYSTEM POWER-UP AND INITIALIZATION
The antilock system is in standby mode with the ignition switch in Off or Accessory position. The antilock electrical components are not operational.
Turning the ignition switch to On or Run position allows battery voltage to flow through the switch to the ECU ignition terminal.
The ABS system is activated when battery voltage is supplied to the ECU. The ECU performs a system initialization procedure at this point. Initialization consists of a static and dynamic self check of system electrical components.
The static check occurs immediately after the ignition switch is turned to the On position. The dynamic check occurs when vehicle road speed reaches approximately 10 kph (6 mph). During the dynamic check, the ECU briefly cycles the pump to verify operation. The HCU solenoids are checked continuously.
If an ABS component exhibits a fault during initialization, the ECU illuminates the amber warning light and registers a fault code in the microprocessor memory.
ABS OPERATION IN NORMAL BRAKING MODE
The ECU monitors wheel speed sensor inputs continuously while the vehicle is in motion. However, the ECU will not activate any ABS components as long as sensor inputs and the acceleration switch indicate normal braking.
During normal braking, the master cylinder, power booster and wheel brake units all function as they would in a vehicle without ABS. The HCU components are not activated.
ABS OPERATION IN ANTILOCK BRAKING MODE
The purpose of the antilock system is to prevent wheel lockup during periods of high wheel slip. Preventing lockup helps maintain vehicle braking action and steering control.
The antilock ECU activates the system whenever sensor signals indicate periods of high wheel slip.
High wheel slip can be described as the point where wheel rotation begins approaching zero (or lockup) during braking. Periods of high wheel slip occur when brake stops involve high pedal pressure and rate of vehicle deceleration.
The antilock system retards lockup during high slip conditions by modulating fluid apply pressure to the wheel brake units.
Brake fluid apply pressure is modulated according to wheel speed, degree of slip and rate of deceleration. A sensor at each wheel converts wheel speed into electrical signals. These signals are transmitted to the ECU for processing and determination of wheel slip and deceleration rate.
The Jeep ABS system has three fluid pressure control channels. The front brakes are controlled separately and the rear brakes in tandem (Fig. 10). A speed sensor input signal indicating high slip conditions activates the ECU antilock program.
Two solenoid valves are used in each antilock control channel (Fig. 11). The valves are all located within the HCU valve body and work in pairs to either increase, hold, or decrease apply pressure as needed in the individual control channels.
The solenoid valves are not static during antilock braking. They are cycled continuously to modulate pressure. Solenoid cycle time in antilock mode can be measured in milliseconds.
HCU SOLENOID VALVE OPERATION
Normal Braking
During normal braking, the HCU solenoid valves and pump are not activated. The master cylinder and power booster operate the same as a vehicle without an ABS brake system.
Antilock Pressure Modulation
Solenoid valve pressure modulation occurs in three stages which are: pressure increase, pressure hold, and pressure decrease. The valves are all contained in the valve body portion of the HCU.
Pressure Decrease
The outlet valve is opened and the inlet valve is closed during the pressure decrease cycle (Fig. 11).
A pressure decrease cycle is initiated when speed sensor signals indicate high wheel slip at one or more wheels. At this point, the ECU opens the outlet valve. Opening the outlet valve also opens the hydraulic return circuit to the master cylinder reser-
5 - 44 ANTILOCK BRAKE SYSTEM OPERATION
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Fig. 10 Three-Channel ABS Hydraulic Control Circuit voir. Fluid pressure is allowed to bleed off (decrease) as needed to prevent wheel lock.
Once the period of high wheel slip has ended, the
ECU closes the outlet valve and begins a pressure increase or hold cycle as needed.
Pressure Hold
Both solenoid valves are closed in the pressure hold cycle (Fig. 12). Fluid apply pressure in the control channel is maintained at a constant rate. The ECU maintains the hold cycle until sensor inputs indicate a pressure change is necessary.
Pressure Increase
The inlet valve is open and the outlet valve is closed during the pressure increase cycle (Fig. 13).
The pressure increase cycle is used to counteract unequal wheel speeds. This cycle controls reapplication of fluid apply pressure after a pressure decrease cycle.
HCU PUMP AND PEDAL TRAVEL SENSOR
OPERATION
The HCU pump has two functions during antilock braking. First, the pump supplies the extra volume of fluid needed. And second, the pump maintains brake pedal height. The fluid source for the pump is the master cylinder reservoir. The reservoir and
HCU are interconnected by hoses.
The pump motor is activated by the ECU. However, the signal to run the pump actually comes from the pedal travel sensor.
The pedal travel sensor is mounted in the forward face of the brake booster (Fig. 14). The sensor
Fig. 11 Solenoid Valves In Pressure Decrease Cycle plunger is actuated by movement of the booster diaphragm plate. The sensor has a total of seven pedal positions, six of which are monitored. The six pedal positions monitored range from full release to full apply. Each pedal position (toward full apply), generates an increasing degree of electrical resistance in the sensor.
The ECU continuously monitors electrical resistance at the pedal travel sensor. The ECU activates the pump whenever sensor electrical resistance increases during ABS mode braking.
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ANTILOCK BRAKE SYSTEM OPERATION 5 - 45
cylinder reservoir by hoses. During antilock braking, the additional volume of fluid needed is drawn by the pump from the reservoir.
Fig. 12 Solenoid Valves In Pressure Hold Cycle
Fig. 13 Solenoid Valves In Pressure Increase Cycle
At the start of antilock braking, pedal height will decrease as the volume of fluid in the master cylinder is used up. When pedal height drops a predetermined amount, the pedal travel sensor will signal the ECU to run the pump. At this point, the pump is activated to supply the extra fluid volume and restore pedal height at the same time.
The pump does not run continuously. It cycles on/ off according to signals from the travel sensor and
ECU. The pump is connected directly to the master
Fig. 14 Pedal Travel Sensor Actuation
WHEEL SPEED SENSOR OPERATION
Wheel speed input signals are generated by a sensor and tone ring at each wheel. The sensors, which are connected directly to the ECU, are mounted on brackets attached to the front steering knuckles and rear brake support plates.
The sensor triggering devices are the tone rings which are similar in appearance to gears. The tone rings are located on the outboard end of each front/ rear axle shaft. The speed sensors generate a signal whenever a tone ring tooth rotates past the sensor pickup face.
The wheel speed sensors provide the input signal to the ECU. If input signals indicate ABS mode braking, the ECU causes the HCU solenoids to decrease, hold, or increase fluid apply pressure as needed.
The HCU solenoid valves are activated only when wheel speed input signals indicate that a wheel is approaching a high slip, or lockup condition. At this point, the ECU will cycle the appropriate wheel control channel solenoid valves to prevent slip or lockup.
The wheel sensors provide speed signals whenever the vehicle wheels are rotating. The ECU examines these signals for degree of deceleration and wheel slip. If signals indicate normal braking, the solenoid valves are not activated. However, when incoming signals indicate the approach of wheel slip, or lockup, the ECU cycles the solenoid valves as needed.
ACCELERATION SWITCH OPERATION
The ECU monitors the acceleration switch at all times. The switch assembly contains three mercury switches that monitor vehicle ride height and deceleration rates (G-force). Sudden, rapid changes in vehicle and wheel deceleration rate, triggers the switch sending a signal to the ECU. The switch assembly provides three deceleration rates; two for forward braking and one for rearward braking.
5 - 46 ANTILOCK BRAKE SYSTEM OPERATION
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ECU OPERATION
The antilock ECU controls all phases of antilock operation. It monitors and processes input signals from all of the system sensors.
It is the ECU that activates the solenoid valves to modulate apply pressure during antilock braking.
The ECU program is able to determine which wheel control channel requires modulation and which fluid pressure modulation cycle to use.
The ECU cycles the solenoid valves through the pressure decrease, hold and increase phases to retard and prevent wheel lock during periods of high wheel slip.
Solenoid valve operation is selective. The solenoid valves may not be cycled simultaneously, nor are they all cycled in the same pressure modulation phase at the same time. The ECU cycles the valves in each control channel as needed. For example, sensor inputs may indicate that only the left front wheel requires modulation during a period of high slip.
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ABS COMPONENT SERVICE 5 - 47
ABS COMPONENT SERVICE
INDEX
page
Acceleration Sensor Installation
. . . . . . . . . . . . . . 52
Acceleration Sensor Removal
. . . . . . . . . . . . . . . 52
Combination Valve Replacement—XJ
Combination Valve Replacement—YJ
Component Serviceability
. . . . . . . . . . . . . . . . . . . 47
Correct Fluid Level
. . . . . . . . . . . . . . . . . . . . . . . 48
ECU Replacement—XJ
. . . . . . . . . . . . . . . . . . . . 53
ECU Replacement—YJ
. . . . . . . . . . . . . . . . . . . . 53
Front Wheel Sensor Installation
. . . . . . . . . . . . . . 49
Front Wheel Sensor Removal
. . . . . . . . . . . . . . . 49
HCU Installation—XJ
. . . . . . . . . . . . . . . . . . . . . . 54
HCU Installation—YJ
. . . . . . . . . . . . . . . . . . . . . . 54
page
HCU Removal—XJ
. . . . . . . . . . . . . . . . . . . . . . . 53
HCU Removal—YJ
. . . . . . . . . . . . . . . . . . . . . . . 54
Importance of Clean Brake Fluid
Master Cylinder Installation
. . . . . . . . . . . . . . . . . 50
Master Cylinder Removal
. . . . . . . . . . . . . . . . . . 50
Pedal Travel Sensor Service
. . . . . . . . . . . . . . . . 51
Power Brake Booster Installation
Power Brake Booster Removal
. . . . . . . . . . . . . . 51
Rear Wheel Sensor Installation
. . . . . . . . . . . . . . 50
Rear Wheel Sensor Removal
. . . . . . . . . . . . . . . 49
Recommended Brake Fluid
. . . . . . . . . . . . . . . . . 48
Wheel Sensor Air Gap Adjustment
COMPONENT SERVICEABILITY
The ABS components are serviced as assemblies
(Figs. 1 and 2); they are not repairable. The following ABS components can be replaced separately:
• center feed master cylinder
• master cylinder-to-booster seal
• power brake booster (includes matched pedal travel sensor)
• booster check valve and grommet
• pedal travel sensor and select fit caps
• combination valve
• HCU and pump motor assembly
• ECU
• acceleration sensor
• wheel sensors
• system wire harnesses
The axle shaft tone wheels are not serviceable. If a tone wheel becomes damaged, it will be necessary to replace the axle shaft, or disc brake rotor and hub assembly on 2-wheel drive models.
Fig. 1 ABS Hydraulic Component Locations (XJ)
5 - 48 ABS COMPONENT SERVICE
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Fig. 2 ABS Hydraulic Component Locations (YJ)
The wheel brake components such as the calipers, brakeshoes, wheel cylinders, rotors and drums are all serviced the same as standard brake system components.
while checking fluid level. Such materials can interfere with solenoid valve operation causing an ABS malfunction.
RECOMMENDED BRAKE FLUID
Recommended brake fluid for the Jeep ABS system is Mopar DOT 3 brake fluid. If Mopar fluid is not readily available, a top quality fluid meeting SAE
J1703 and DOT 3 standards can be used.
Brake fluid used in the ABS system must meet the
SAE and DOT quality standards and be exceptionally clean. Never use substandard fluid, fluid not meeting the SAE and DOT standards, reclaimed fluid, or fluid from open containers.
CORRECT FLUID LEVEL
Correct brake fluid level is marked on the driver side of the master cylinder reservoir (Fig. 3).
Preferred fluid level is to the MAX indicator mark.
Acceptable fluid level is between the MAX and MIN marks.
If fluid level is at or below the MIN mark, the brake hydraulic system should be checked for leaks.
CAUTION: Clean the reservoir caps and exterior thoroughly before checking fluid level. Do not allow any dirt or foreign material to enter the reservoir
Fig. 3 Reservoir Fluid Level Indicators
IMPORTANCE OF CLEAN BRAKE FLUID
The antilock system brake fluid must be kept clean and uncontaminated. Foreign material in the fluid, or non-recommended fluids will cause system malfunctions.
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ABS COMPONENT SERVICE 5 - 49
Clean the reservoir and caps thoroughly before checking level or adding fluid. Cap open lines and hoses during service to prevent dirt entry.
Dirt or foreign material entering the ABS hydraulic system through the reservoir opening will circulate within the system. The result will be poor brake performance and possible component failure. Use clean, fresh fluid only to top off, or refill the system.
(7) Attach sensor wire to sill bracket with grommet. Be sure wire is free of twists and kinks.
(8) Verify sensor wire routing. Wire should loop forward and above sill bracket. Loose end of wire should be below sill bracket and towards brake hose.
(9) Seat sensor wire grommet in body panel and clip wire to brake line at grommet location.
(10) Connect sensor wire to harness in engine compartment.
WHEEL SENSOR AIR GAP ADJUSTMENT
Only rear sensor air gap is adjustable. The front sensors are fixed and cannot be adjusted.
A rear sensor air gap adjustment is only needed when reinstalling an original sensor. Replacement sensors have an air gap spacer attached to the sensor pickup face. The spacer establishes correct air gap when pressed against the tone ring during installation. As the tone ring rotates, it peels the spacer off the sensor to create the required air gap.
Preferred rear sensor air gap is 1.1 mm (0.043 in.).
Acceptable air gap range is 0.92 to 1.275 mm (0.036
to 0.050 in.).
Front sensor air gap is not adjustable. The front sensors are fixed in position and cannot be adjusted.
Front sensor air gap can only be checked. Air gap should be 0.040 to 1.3 mm (0.0157 to 0.051 in.). If front sensor air gap is incorrect, the sensor is either loose, or damaged.
REAR WHEEL SENSOR REMOVAL
(1) On XJ models, if separate connectors are not used to attach sensor harness to each sensor wire, proceed as follows:
(a) Raise and fold rear seat forward for access to rear sensor connectors (Figs. 4 and 5).
(b) Disconnect sensors at rear harness connectors.
(c) Push sensor grommets and sensor wires through floorpan.
FRONT WHEEL SENSOR REMOVAL
(1) Raise vehicle and turn wheel outward for easier access to sensor.
(2) Remove sensor wire from mounting brackets.
(3) Clean sensor and surrounding area before removal.
(4) Remove bolt attaching sensor to steering knuckle and remove sensor.
(5) Unseat grommet retaining sensor wire in wheel house panel.
(6) In engine compartment, disconnect sensor wire connector at harness plug. Then remove sensor and wire.
FRONT WHEEL SENSOR INSTALLATION
(1) Apply Mopar Lock N’ Seal or Loctite 242 to bolt that attaches sensor to steering knuckle. Use new sensor bolt if original bolt is worn or damaged.
(2) Position sensor on steering knuckle. Seat sensor locating tab in hole in knuckle and install sensor attaching bolt finger tight.
(3) Tighten sensor bolt to 14 N I m (11 ft. lbs.) torque.
(4) Attach sensor wire to steering knuckle bracket with grommets on sensor wire.
(5) Route sensor wire forward and behind shock absorber. Then attach sensor wire to spring seat bracket with grommets on sensor wire.
(6) Route sensor wire to outer sill bracket. Remove all twists or kinks from wire.
Fig. 4 Acceleration Switch And Rear Sensor
Connections (XJ)
Fig. 5 Rear Sensor Connections (XJ)
5 - 50 ABS COMPONENT SERVICE
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(2) Raise vehicle.
(3) Disconnect sensor wires at rear axle connectors.
(4) Remove wheel and tire assembly.
(5) Remove brake drum.
(6) Remove clips securing sensor wires to brake lines or rear axle and rear brake hose.
(7) Unseat sensor support plate grommet.
(8) Remove bolt attaching sensor to bracket and remove sensor.
REAR WHEEL SENSOR INSTALLATION
(1) Insert sensor wire through support plate hole and seat sensor grommet in support plate.
(2) Apply Mopar Lock N’ Seal or Loctite 242 to original sensor bolt. Use new bolt if original is worn or damaged.
(3) Install sensor bolt finger tight only at this time.
(4) Set sensor air gap as follows:
(a) If original sensor is being installed, remove any remaining pieces of cardboard spacer from sensor pickup face. Then adjust air gap to preferred setting of 1.1 mm (0.043 in.) with brass feeler gauge (Fig. 6). Tighten sensor bolt to 11 N z m (11 ft.
lbs.) torque.
(b) If new sensor is being installed, push cardboard spacer on sensor face (Fig. 7) against tone ring. Then tighten sensor bolt to 8 N z m (6 ft. lbs.) torque. Correct air gap will be established as tone ring rotates and peels spacer off sensor face.
(c) Verify sensor air gap adjustment. If adjustment changed after tightening bolt, readjust sensor air gap as needed.
Fig. 6 Setting Air Gap On Original Rear Sensor
(5) On YJ, connect rear sensor wires to connectors at axle. On XJ, route sensor wires to rear seat area.
(6) Feed sensor wires through floorpan access hole and seat sensor grommets in floorpan.
(7) Verify that rear sensor wire are secured to rear brake hose and axle with clips. Verify that wire is clear of rotating components.
(8) Install brake drum and wheel.
(9) Lower vehicle.
(10) On XJ, connect sensor wire to harness connector. Then reposition carpet and fold rear seat down.
Fig. 7 New Rear Sensor With Air Gap Spacer
MASTER CYLINDER REMOVAL
(1) Disconnect pedal travel sensor wires.
(2) Remove air cleaner and hoses on XJ models.
(3) Remove clamps that secure reservoir hoses to
HCU pipes.
(4) Position small drain container under master cylinder reservoir. Remove reservoir hoses from HCU pipes and allow fluid to drain into container before removing reservoir. Discard fluid drained from reservoir.
(5) Pump brake pedal to exhaust all vacuum from power brake booster.
(6) Disconnect necessary brakelines at master cylinder and combination valve. Also remove combination valve bracket bolt.
(7) Remove nuts attaching master cylinder to booster mounting studs.
(8) Remove master cylinder. Pull cylinder forward and off studs. Then work cylinder past combination valve, brakelines, pedal travel sensor and out of engine compartment.
MASTER CYLINDER INSTALLATION
(1) If new master cylinder is being installed, bleed cylinder on bench before installing it in vehicle.
(2) Work master cylinder into position and install it in booster. Be sure cylinder is properly seated on booster studs. Also be sure booster-to-cylinder seal is not displaced during installation.
(3) Connect reservoir hoses to HCU pipes.
(4) Verify that master cylinder and booster are properly connected.
(5) Install and tighten master cylinder attaching nuts to 34 N z m (25 ft. lbs.) torque.
(6) Connect brakelines to master cylinder.
(7) Install combination valve, if removed and install bolt that secures valve bracket to master cylinder.
(8) Connect sensor wires.
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(9) Fill reservoir and bleed brakes. Refer to procedure in this section.
(10) Install air cleaner and hoses.
PEDAL TRAVEL SENSOR SERVICE
CAUTION: The pedal travel sensor and booster must form a matched set. The cap on the sensor plunger and booster shell are color coded for identification, and to ensure they are used as matched sets. Be sure the color of the sensor cap and the color dot on the booster shell are the same before installation. Refer to the Sensor Replacement information before installing a new or original sensor.
ABS COMPONENT SERVICE 5 - 51
PEDAL TRAVEL SENSOR REMOVAL
(1) Disconnect wires at sensor.
(2) Pump brake pedal to exhaust all vacuum from booster.
(3) Unseat sensor retaining ring.
(4) Remove sensor from booster (Fig. 8).
PEDAL TRAVEL SENSOR REPLACEMENT
A new pedal travel sensor is supplied with four different color caps. The caps are color coded to ease matching them with the color code dot on the booster shell.
Compare the color of the new sensor cap and the color dot on the booster shell. If the colors match, proceed with sensor installation. However, if the colors do not match, select and install the correct color cap on the sensor plunger before proceeding.
PEDAL TRAVEL SENSOR INSTALLATION
(1) Check color dot on face of brake booster. Then check color of cap on sensor plunger. If colors match, proceed with installation. If colors do not match, install correct color cap on end of plunger.
(2) Install O-ring on sensor.
(3) Install sensor retaining ring on booster flange.
(4) Insert sensor in retaining ring and booster.
(5) Verify that retaining ring is properly engaged in sensor and that sensor is seated in booster.
(6) Connect wires to sensor.
(7) Check sensor operation with DRB II scan tool.
POWER BRAKE BOOSTER REMOVAL
(1) Pump brake pedal until all vacuum is exhausted from power brake booster.
(2) Disconnect pedal travel sensor.
(3) Remove air cleaner and hoses.
(4) Remove clamps that secure reservoir hoses to
HCU pipes. Then remove hoses from pipes.
(5) Disconnect brakelines at master cylinder.
(6) Remove combination valve bracket bolt if necessary.
(7) Remove nuts attaching master cylinder to booster mounting studs.
Fig. 8 Pedal Travel Sensor Mounting
(8) Remove master cylinder. Pull cylinder forward and off studs. Then work cylinder past combination valve, brakelines, pedal travel sensor and out of engine compartment.
(9) Disconnect vacuum hose at booster check valve.
(10) Disconnect booster push rod from brake pedal.
(11) Remove nuts attaching booster to passenger compartment side of dash panel.
(12) Slide booster forward and work it out of engine compartment.
POWER BRAKE BOOSTER INSTALLATION
(1) Position booster on dash panel. Align booster mounting studs with holes in panel and seat booster
(Fig. 9).
Fig. 9 Booster Attachment At Dash Panel—YJ
Shown
(2) In passenger compartment, install booster attaching nuts on mounting studs. Tighten attaching nuts to 41 N z m (30 ft. lbs.) torque.
(3) Install seal on master cylinder. Seal is slight interference fit to help hold it in place.
5 - 52 ABS COMPONENT SERVICE
CAUTION: The pedal travel sensor and booster must form a matched set. The cap on the sensor plunger and the color dot on the booster shell are color coded for identification, and to ensure they are used as matched sets. Be sure the color on the sensor cap and booster shell are the same before installation. Refer to the Sensor Replacement information before installing a new or original sensor.
(4) If new pedal travel sensor is being installed in original booster, compare color dot on booster shell with color of cap on sensor (Fig. 10). If both are same color, proceed with installation. However, if colors do not
match, select correct color cap from kit supplied with new sensor and install it on end of sensor plunger.
(5) Install O-ring on pedal travel sensor.
(6) Install sensor retaining ring on booster flange.
Be sure retaining ring is firmly seated.
(7) Insert sensor into booster. Be sure sensor is fully seated and engaged in retaining ring.
(8) Connect booster push rod to brake pedal.
(9) Attach vacuum hose to booster check valve.
(10) Install master cylinder on booster. Tighten cylinder attaching nuts to 25-30 N z m (220-267 in.
lbs.) torque.
(11) Connect brakelines to master cylinder.
(12) Install combination valve bracket bolt if removed.
(13) Connect reservoir hoses to HCU pipes.
(14) Connect sensor wires.
(15) Bleed brakes. Refer to procedure in this section.
(16) Install air cleaner and hoses.
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Fig. 10 Booster Push Rod And Pedal Travel Sensor
ACCELERATION SENSOR REMOVAL
(1) On XJ models, tilt rear seat assembly forward for access to sensor (Fig. 11).
(2) On YJ models, move driver seat forward or rearward for access to sensor and mounting bracket
(Fig. 11).
(3) Disconnect sensor harness (Fig. 10).
(4) On XJ models, remove screws attaching sensor to bracket. Then remove sensor.
(5) On YJ models, remove screws attaching sensor bracket to floorpan. Then remove sensor from bracket.
Fig. 11 Acceleration Sensor Mounting
ACCELERATION SENSOR INSTALLATION
(1) Note position of locating arrow on sensor. Sensor must be positioned so arrow faces forward.
CAUTION: The sensor mercury switch will not function properly if the sensor is mispositioned. Verify that the sensor locating arrow is pointing to the front of the vehicle.
(2) Position sensor in mounting bracket (Fig. 10).
(3) Install and tighten sensor attaching screws to
2-4 N z m (17-32 in. lbs.) torque.
(4) Connect harness to sensor. Be sure harness connecter is firmly seated.
(5) Move seat back to normal position.
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ECU REPLACEMENT—XJ
ECU Removal
(1) Turn ignition key to Off position.
(2) Remove screws attaching ECU to mounting bracket (Fig. 12).
(3) Disconnect ECU wiring harness.
(4) Remove ECU.
ABS COMPONENT SERVICE 5 - 53
Fig. 13 ECU Location (YJ)
(3) Position suitable size fluid drain container under master cylinder reservoir hoses. Disconnect reservoir hoses from HCU and drain fluid into container.
Discard old fluid and remove reservoir.
(4) Disconnect pump motor and solenoid harness wires at HCU (Fig. 15).
Fig. 12 Antilock ECU Mounting (XJ)
ECU Installation
(1) If new ECU is being installed, transfer mounting bracket to new ECU.
(2) Tighten ECU-to-mounting bracket screws to
8-13 N z m (75-115 in. lbs.) torque.
(3) Connect wire harness to ECU.
(4) Position and install ECU.
(5) Tighten ECU attaching nuts to 10-14 N z m (85-
125 in. lbs.) torque.
ECU REPLACEMENT—YJ
The antilock electronic control unit (ECU) is attached to the dash panel inside the passenger compartment. It is positioned just above the heater/air conditioning plenum housing, in line with the glove box (Fig. 13).
The ECU is attached to the dash panel by bolts and nuts that are accessible from the engine compartment. The fasteners are located just to the right of the battery.
On models with air conditioning, it will be necessary to remove the air conditioning fascia panel and ducts for access to the ECU and harness connecter.
HCU REMOVAL—XJ
(1) Remove air cleaner.
(2) Remove clamp that secures air cleaner hose and pipe to fender apron (Fig. 14).
Fig. 14 Air Cleaner And Harness Connector Location (XJ)
Fig. 15 HCU Wire Harness Connections
5 - 54 ABS COMPONENT SERVICE
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(5) Mark or tag HCU hydraulic lines for assembly reference.
(6) Disconnect hydraulic lines at HCU.
(7) Move HCU harness and air cleaner hose pipe aside for access to HCU bracket nuts.
(8) Remove single bolt and two nuts attaching
HCU to mounting bracket on inner fender panel
(Figs. 16 and 17).
(9) Remove HCU. Lift HCU up and off mounting bracket studs. Then work HCU past brakelines and master cylinder to remove it.
(3) Connect hydraulic lines to HCU (Fig. 18). Line fitting nuts and bosses on valve body ports are color coded. Be sure lines are properly connected.
Fig. 16 HCU Mounting (Left Hand Drive XJ)
Fig. 17 HCU Mounting (Right Hand Drive XJ)
HCU INSTALLATION—XJ
(1) Connect master cylinder reservoir hoses to
HCU pipes.
(2) Position HCU assembly on mounting bracket and install attaching nuts.
Fig. 18 HCU Hydraulic Line Connections
(4) Connect HCU harness wires to HCU.
(5) Check routing of HCU lines/hoses. Be sure lines are not kinked and are clear of engine components.
(6) Fill master cylinder reservoir with Mopar DOT
3 brake fluid or equivalent.
(7) Bleed brake system.
(8) Install air cleaner and hoses. Secure air cleaner hose pipe to fender apron with clamp.
(9) Check brake pedal action. Bleed brakes again if pedal is not firm (feels soft/spongy).
HCU REMOVAL—YJ
(1) Place shop towels or small container under master cylinder reservoir hoses.
(2) Disconnect master cylinder reservoir hoses at
HCU.
(3) Disconnect all sensor and harness wires at
HCU.
(4) Disconnect brakelines at HCU (Fig. 19). Mark or tag lines for installation reference.
(5) Remove bolt and nuts attaching HCU mounting bracket to fender apron and remove HCU.
HCU INSTALLATION—YJ
(1) Position HCU on fender apron (Figs. 2 and 19) and install attaching bolts/nuts.
(2) Connect brakelines to HCU.
(3) Connect harness and sensor wires to HCU.
(4) Connect master cylinder reservoir hoses to
HCU.
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ABS COMPONENT SERVICE 5 - 55
Fig. 19 HCU Mounting (YJ)
(5) Fill and bleed brake system.
COMBINATION VALVE REPLACEMENT—XJ
The combination valve is not a repairable component. The valve is serviced as an assembly whenever diagnosis indicates replacement is necessary.
(1) Remove air cleaner housing for access to valve, if necessary.
(2) Remove bolt attached valve to master cylinder
(Fig. 20).
(3) Disconnect pedal travel sensor harness connector and move harness wires aside for working access if necessary.
(4) Disconnect pressure differential switch wires at valve.
(5) Disconnect hydraulic lines at valve and remove valve from vehicle.
(6) Connect hydraulic lines to valve.
(7) Position valve bracket on master cylinder and install bracket attaching bolt.
Fig. 20 Combination Valve Mounting (XJ)
(8) Reconnect pressure differential switch and pedal travel sensor wires.
(9) Bleed brake system. Refer to procedure in this section.
COMBINATION VALVE REPLACEMENT—YJ
The combination valve mounting bracket is permanently attached to the valve. The bracket and valve are serviced as an assembly.
(1) Disconnect harness wires from combination valve switch.
(2) Disconnect brakelines attached to combination valve.
(3) Remove nuts attaching combination valve bracket to master cylinder mounting studs (Fig. 19).
(4) Remove valve and bracket as assembly.
(5) Start all brakelines in combination valve by hand. Tighten line fittings just enough to prevent leaks.
(6) Position valve mounting bracket on studs.
(7) Install and tighten nuts that attach combination valve bracket to studs on power brake booster.
(8) Connect wires to combination valve switch.
(9) Fill and bleed brake system.
(10) Final-tighten brakeline fittings to 18-23 N z m
(160-210 in. lbs.) torque after bleeding brakes.
5 - 56 PARKING BRAKES
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PARKING BRAKES
INDEX
page
General Service Information
. . . . . . . . . . . . . . . . 56
Parking Brake Adjustment (XJ/YJ)
Parking Brake Cable Tensioner Replacement (XJ)
Parking Brake Front Cable Replacement (YJ)
Parking Brake Lever Installation
(XJ with Full Console)
. . . . . . . . . . . . . . . . . . . 60
Parking Brake Lever Installation
(XJ with Mini Console)
. . . . . . . . . . . . . . . . . . . 58
Parking Brake Lever Installation
(XJ Without Console)
. . . . . . . . . . . . . . . . . . . . 60
page
Parking Brake Lever Removal
(XJ with Full Console)
. . . . . . . . . . . . . . . . . . . . 59
Parking Brake Lever Removal
(XJ with Mini Console)
. . . . . . . . . . . . . . . . . . . 58
Parking Brake Lever Removal (XJ Without Console) . 60
Parking Brake Operation
. . . . . . . . . . . . . . . . . . . 56
Parking Brake Pedal Installation (YJ)
Parking Brake Pedal Removal (YJ)
Parking Brake Rear Cable Replacement (XJ)
Parking Brake Rear Cable Replacement (YJ)
GENERAL SERVICE INFORMATION
Parking brake adjustment is controlled by a cable tensioner mechanism. The tensioner mechanism is used on 1991 through 1994 YJ models and XJ models starting with 1992 models. The cable tensioner, once adjusted at the factory, will not need further adjustment under normal circumstances. There are only two instances when adjustment is required. The first is when a new tensioner, or cables have been installed.
And the second, is when the tensioner and cables are disconnected for access to other brake components.
rectly to the hand lever (a front cable is not used).
The tensioner rod is attached to the equalizer which is the connecting point for the rear cables (Fig. 2).
The rear cables are connected to the actuating lever on each secondary brakeshoe. The levers are attached to the brakeshoes by a pin either pressed into, or welded to the lever. A clip is used to secure the pin in the brakeshoe. The pin allows each lever to pivot independently of the brakeshoe.
Struts, installed between each brakeshoe, are used to maintain shoe alignment and equal motion when the parking brakes are applied. Each strut is equipped with a combination tension and anti-rattle spring.
PARKING BRAKE OPERATION
The rear brakes are utilized for the parking brake function. They are actuated hydraulically during normal brake operation but are mechanically actuated for parking brake operation.
Parking Brake Components
The rear brakeshoes are applied by a system of levers and cables for parking brake operation. A foot or hand operated lever in the passenger compartment is the main application device. Actuating levers on the secondary brakeshoes move the shoes directly into contact with the drum braking surface. The actuating levers are interconnected by a system of cables and a tensioner mechanism. The tensioner mechanism controls parking brake adjustment.
On XJ models, the cable tensioner is part of the lever assembly. On YJ models, the tensioner and equalizer are mounted in a bracket attached to the underbody.
On YJ models, the parking brake front cable is attached to the foot pedal at one end and the cable tensioner at the other. The tensioner is connected to the equalizer which is the connecting device for the rear cables (Fig. 1).
On XJ models, the cable tensioner is connected di-
Parking Brake Application
To apply the parking brakes, the foot pedal is pressed downward, or the hand lever is pulled upward, to an engaged position. This pulls the rear brakeshoe actuating levers forward, by means of the interconnected tensioner and cables.
As the actuating lever is pulled forward, the parking brake strut (which is connected to both shoes), exerts a linear force against the primary brakeshoe.
This action presses the primary shoe into contact with the drum.
Once the primary shoe contacts the brake drum, force exerted through the strut does not end. Instead, further lever movement continues to exert force against the strut; only this time, in a reverse direction. The strut force then causes the secondary shoe to pivot into contact with the drum as well.
The brakeshoes will remain engaged with the drum until the levers and cables are released. A gear type ratcheting mechanism is used to hold the pedal or lever in an applied position. Parking brake release is accomplished by means of the release handle on
YJ models. Or by the hand lever release button on
XJ models.
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PARKING BRAKES 5 - 57
Fig. 1 Parking Brake Components (YJ)
Fig. 2 Parking Brake Components (XJ)
5 - 58 PARKING BRAKES
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PARKING BRAKE LEVER REMOVAL (XJ WITH MINI
CONSOLE)
(1) Release parking brakes, if necessary.
(2) Raise vehicle.
(3) Remove adjusting nut from tensioner rod (Fig.
2). Then secure equalizer and rear cables to chassis with wire.
(4) Remove nuts attaching lever support plate to underside of floorpan. Then move plate aside.
(5) Lower vehicle.
(6) Remove lever assembly from floorpan.
(7) Remove tensioner cover and boot for access to lever arm (Fig. 3).
(8) Remove E-clip and pin that connect tensioner to lever arm (Fig. 3).
(9) Remove lever attaching screws from floorpan
(Fig. 4).
(10) Remove lever assembly.
PARKING BRAKE LEVER INSTALLATION (XJ WITH
MINI CONSOLE)
(1) Assemble lever and tensioner components
(Figs. 3 and 4). Be sure E-clip is fully seated in pin
(Fig. 3).
(2) Verify that tensioner boot is properly seated in cover (Fig. 5).
(3) Position lever assembly on floorpan and install lever attaching screws, if equipped.
Fig. 3 Tensioner E-Clip And Retaining Pin Location
(4) Raise vehicle.
(5) Insert cable tensioner rod in equalizer and install adjusting nut on tensioner rod.
(6) Install and tighten nuts that attach lever support plate to floorpan and lever screws.
(7) Adjust parking brakes. Refer to procedure in this section.
(8) Lower vehicle and verify correct parking brake operation.
Fig. 4 Mini Console And Parking Brake Lever Cover (XJ)
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PARKING BRAKES 5 - 59
Fig. 5 Tensioner Boot Seated In Cover
PARKING BRAKE LEVER REMOVAL (XJ WITH FULL
CONSOLE)
(1) Release parking brakes, if necessary.
(2) Raise vehicle.
(3) Remove adjusting nut from tensioner rod. Then temporarily secure equalizer to nearby chassis component with wire.
(4) Remove nuts attaching lever support plate to underside of floorpan.
(5) Lower vehicle.
(6) On models with manual transmission, remove shift knob, boot and bezel.
(7) On models with automatic transmission, remove shift handle cap and remove plunger, spring and T-lock (Fig. 7).
(8) Remove shift handle and shift bezel (Fig. 7).
(9) Remove console cover screws (Fig. 8).
Fig. 7 Automatic Transmission Shift Handle
(10) On models with power mirror switch, pry switch out of console cover and disconnect switch connector (Fig. 8).
(11) Remove console cover from base (Fig. 9).
(12) Remove console base.
(13) Disconnect brake warning light wire connector at lever.
(14) Remove lever and cable tensioner assembly from floorpan.
(15) Move cover and boot aside for access to lever arm (Fig. 3).
(16) Remove E-clip and pin that connect tensioner to lever arm (Fig. 3).
Fig. 6 Hand Lever And Cable Tensioner Components (XJ)
5 - 60 PARKING BRAKES
Fig. 8 Console Cover Screws And Power Mirror
Switch Connector
Fig. 9 Console Cover And Base
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PARKING BRAKE LEVER INSTALLATION (XJ WITH
FULL CONSOLE)
(1) Assemble lever and tensioner (Figs. 3 and 4).
Be sure E-clip is fully engaged in retaining pin (Fig.
3).
(2) Verify that tensioner boot is fully seated in cover (Fig. 5).
(3) Position assembled lever and tensioner in floorpan.
(4) Connect brake warning light wires to switch on lever.
(5) Install console base and cover.
(6) Connect power mirror switch wire to switch and install switch in console cover.
(7) On automatic transmission models, install shift bezel and shift handle.
(8) On manual transmission models, install boot, bezel and shift knob.
(9) Raise vehicle.
(10) Insert tensioner rod in equalizer and install adjusting nut on tensioner rod.
(11) Install nuts attaching lever support plate to floorpan and lever.
(12) Adjust parking brakes. Refer to procedure in this section.
PARKING BRAKE LEVER REMOVAL (XJ WITHOUT
CONSOLE)
(1) Raise vehicle.
(2) Remove nuts attaching lever support plate to underside of floorpan.
(3) Remove adjusting nut from tensioner rod. Then temporarily secure equalizer and cables to nearby chassis component with wire.
(4) Lower vehicle.
(5) Raise lever cover at rear and tilt it forward
(Fig. 10).
(6) Remove cover attaching screws. Or, if cover is attached with rivets, drill out and remove cover.
(7) Disconnect brake warning light wire at lever.
(8) Remove lever and tensioner assembly from floorpan.
(9) Move cover and boot aside for access to tensioner retaining pin and clip.
(10) Remove pin and E-clip that secure tensioner to lever arm and separate lever and tensioner.
PARKING BRAKE LEVER INSTALLATION (XJ
WITHOUT CONSOLE)
(1) Assemble lever and tensioner (Figs. 3 and 4).
(2) Verify that tensioner boot is properly seated in cover (Fig. 5).
(3) Position lever on floorpan and insert lever screws through floorpan. Be sure lever cover and seal are in place between lever and floorpan.
(4) Connect brake warning light wires to switch on lever.
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PARKING BRAKES 5 - 61
(13) Align cover and seal on lever flange.
(14) Verify that tensioner boot is seated in cover
(Fig. 5).
(15) Install assembled lever and tensioner in floorpan.
(16) Install necessary console components.
(17) Adjust parking brakes as described in this section.
PARKING BRAKE PEDAL REMOVAL (YJ)
(1) Raise vehicle.
(2) Loosen equalizer nuts until front cable is slack
(Fig. 11).
Fig. 10 Lever Cover (XJ)
(5) Install lever cover. Secure cover with new rivets, or original attaching screws.
(6) Raise vehicle.
(7) Connect tensioner to lever with retaining pin and E-clip.
(8) Install nuts attaching lever support plate to lever screws.
(9) Adjust parking brakes. Refer to procedure in this section.
PARKING BRAKE CABLE TENSIONER
REPLACEMENT (XJ)
(1) Raise vehicle.
(2) Remove adjuster nut from tensioner rod. Secure equalizer and cables to nearby chassis component with wire.
(3) Remove nuts attaching lever assembly to support plate and floorpan.
(4) Lower vehicle.
(5) Remove console components and lever assembly cover.
(6) Remove lever and tensioner assembly.
(7) Move cover and boot for access to tensioner retaining pin.
(8) Remove E-clip and pin that attach tensioner to lever arm (Fig. 3).
(9) Remove tensioner from cover.
E-clip.
(12) Verify that E-clip is fully engaged in pin (Fig.
3).
(10) Transfer boot to new tensioner if necessary.
(11) Attach tensioner to lever arm with pin and
Fig. 11 Front Cable And Equalizer (YJ)
(3) Lower vehicle.
(4) Remove dash-to-instrument panel brace rod, if equipped.
(5) Disconnect warning light switch wire from pedal assembly.
(6) On some YJ models, a ground wire may be attached to upper end of bolt that secures parking brake pedal to instrument panel. Wire is secured with a nut. Be sure to remove nut and detach ground wire before proceeding. If this wire is not removed beforehand, wire and harness could be damaged when pedal assembly bolt is removed. Ground wire and attaching nut are accessible from under instrument panel.
(7) Remove bolt securing pedal assembly to instrument panel (Fig. 12).
(8) In engine compartment, remove pedal mounting stud nuts.
(9) Remove pedal assembly from panel.
(10) Disengage front cable from retainer (Fig. 12).
(11) Squeeze cable clip (Fig. 12) and pull cable out of pedal frame.
(12) Remove pedal assembly.
PARKING BRAKE PEDAL INSTALLATION (YJ)
(1) Connect front cable to pedal retainer.
5 - 62 PARKING BRAKES
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Fig. 12 Parking Brake Pedal Assembly (YJ)
(2) Position pedal assembly on panel and install mounting stud nuts and pedal-to-dash bolt.
(3) Install ground wire on upper end of pedal-todash bolt and secure wire with attaching nut.
(4) Connect warning light switch wire to pedal connector.
(5) Install dash-to-instrument panel brace rod, if equipped.
(6) Raise vehicle and adjust brake cables. Refer to procedure in Service Adjustment section.
PARKING BRAKE REAR CABLE REPLACEMENT (XJ)
(1) Raise vehicle and loosen equalizer nuts until rear cables are slack.
(2) Disengage cable from equalizer and remove cable clip and spring (Fig. 13).
(3) Remove rear wheel and brake drum.
(4) Remove secondary brakeshoe and disconnect cable from lever on brakeshoe.
(5) Compress cable retainer with worm drive hose clamp (Fig. 14) and remove cable from backing plate.
(6) Install new cable in backing plate. Be sure cable retainer is seated.
(7) Attach cable to lever on brakeshoe and install brakeshoe on backing plate.
(8) Adjust brakeshoes to drum with brake gauge.
(9) Install brake drum and wheel.
(10) Engage cable in equalizer and install equalizer nuts (Fig. 13).
(11) Adjust parking brakes. Refer to procedure in this section.
PARKING BRAKE FRONT CABLE REPLACEMENT
(YJ)
(1) Raise vehicle.
(2) Remove equalizer nuts (Fig. 15).
(3) Remove front cable from equalizer (Fig. 15).
(4) Remove cable-to-frame bracket clip.
(5) Lower vehicle.
Fig. 13 Parking Brake Cables (XJ)
Fig. 14 Compressing Rear Cable Retainer
(6) Move front carpeting away from pedal.
(7) Compress clip securing cable to pedal frame
(Fig. 15). Use hose clamp to compress clip.
(8) Disconnect cable from pedal retainer and remove cable.
(9) Remove grommet (Fig. 15) from old cable and transfer it to new cable, if necessary.
(10) Install new cable in floorpan and connect it to pedal assembly.
(11) Seat cable grommet in floorpan.
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PARKING BRAKES 5 - 63
Fig. 15 Parking Brake Cables (YJ)
(12) Raise the vehicle.
(13) Install cable-to-frame retaining clip.
(14) Insert cable in equalizer and install equalizer washer and nuts.
(15) Adjust parking brakes as described in Service
Adjustment section.
PARKING BRAKE REAR CABLE REPLACEMENT (YJ)
(1) Raise vehicle and loosen equalizer nuts (Fig.
15).
(2) Remove clamp and cotter pin attaching rear cable to equalizer and remove cable.
(3) Remove cable clips.
(4) Remove rear wheel and brake drum.
(5) Remove secondary brakeshoe and disconnect cable from lever on brakeshoe.
(6) Compress cable retainer with hose clamp (Fig.
14) and remove cable from backing plate.
(7) Install new cable in backing plate. Be sure cable retainer lock tabs are engaged in plate.
(8) Install secondary brakeshoe.
(9) Adjust brakeshoes to brake drum and install drum and wheel.
(10) Install cable in equalizer. Secure cable with retainer and cotter pin.
(11) Install cable clips.
(12) Adjust parking brakes. Refer to procedure in this section.
PARKING BRAKE ADJUSTMENT (XJ/YJ)
Parking brake adjustment is only necessary when the tensioner, or a cable has been replaced or disconnected for service. When adjustment is necessary, perform adjustment only as described in the following procedure. This is necessary to avoid faulty parking brake operation.
(1) Raise vehicle.
(2) Back off tensioner adjusting nut to create slack in cables.
(3) Remove rear wheel/tire assemblies and remove brake drums.
(4) Check rear brakeshoe adjustment with standard brake gauge. Also check condition of brake parts as follows:
(a) Replace worn parts if necessary. Excessive shoe-to-drum clearance, or worn brake components will result in faulty parking brake adjustment and operation.
(b) Verify that parking brake cables operate freely and are not binding, or seized. Replace faulty cables, before proceeding.
(c) Adjust rear brakeshoes shoes to drum.
(5) Reinstall brake drums and wheel/tire assemblies after brakeshoe adjustment is complete.
5 - 64 PARKING BRAKES
J
(6) Lower vehicle enough for access to parking brake lever or foot pedal. Then fully apply parking brakes. Leave brakes applied until adjustment is complete.
(7) Raise vehicle again.
(8) Mark tensioner rod 6.5 mm (1/4 in.) from tensioner bracket (Fig. 16).
(9) Tighten adjusting nut at equalizer until mark on tensioner rod moves into alignment with tensioner bracket (Fig. 16). Do not loosen/tighten equalizer adjusting nut for any reason after completing adjustment.
(10) Lower vehicle until rear wheels are 15-20 cm
(6-8 in.) off shop floor.
(11) Release parking brake lever and verify that rear wheels rotate freely without drag.
(12) Lower vehicle.
Fig. 16 Placing Adjustment Mark On Tensioner Rod
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BRAKE PEDAL AND BRAKELIGHT SWITCH 5 - 65
BRAKE PEDAL AND BRAKELIGHT SWITCH
INDEX
page
Brake Pedal Installation
. . . . . . . . . . . . . . . . . . . . 66
Brake Pedal Removal
. . . . . . . . . . . . . . . . . . . . . 65
Brake Pedal Service
. . . . . . . . . . . . . . . . . . . . . . 65
Brakelight Switch Adjustment
. . . . . . . . . . . . . . . . 66
page
Brakelight Switch Installation
. . . . . . . . . . . . . . . . 66
Brakelight Switch Removal
. . . . . . . . . . . . . . . . . 66
General Information
. . . . . . . . . . . . . . . . . . . . . . . 65
GENERAL INFORMATION
A suspended-type brake pedal is used on all models
(Figs. 1 and 2). The pedal pivots on a shaft mounted in the pedal support bracket. The bracket is attached to the dash and instrument panels on all models.
A plunger-type, adjustable brakelight switch is used on all models. The switch is attached to a flange on the pedal support bracket.
BRAKE PEDAL SERVICE
The brake pedal is a serviceable component. The pedal, pivot pin, sleeve, pedal bushings and spacers/ washers are all replaceable parts. The pedal bracket can also be replaced when necessary.
BRAKE PEDAL REMOVAL
(1) Remove lower trim panel and A/C duct if necessary.
(2) Remove steering column lower trim panel and bezel.
(3) Remove necessary dash panel-to-instrument panel brace rods.
Fig. 1 Brake Pedal And Support Bracket (YJ)
Fig. 2 Brake Pedal And Support Bracket (XJ)
5 - 66 BRAKE PEDAL AND BRAKELIGHT SWITCH
J
(4) Remove retainer clip securing booster push rod to pedal (Fig. 3).
(5) Remove nut securing pedal shaft in support bracket.
(6) Slide pedal shaft outward for clearance and remove brake pedal.
(7) Remove pedal bushings if they are to be replaced.
BRAKELIGHT SWITCH INSTALLATION
(1) Insert replacement switch in retainer. Thread switch into place or rock it up/down until switch plunger touches brake pedal.
(2) Connect switch wires.
(3) Check switch operation. Adjust switch position if necessary. Refer to procedures in this section.
(4) Install trim panels (if removed).
BRAKELIGHT SWITCH ADJUSTMENT
A plunger-type brakelight switch is used on XJ and YJ models (Fig. 4). The switch plunger is actuated directly by the brake pedal.
The switch internal contacts are open when the brake pedal is in the released position. Brake application moves the pedal away from the switch allowing the plunger to extend. As the plunger extends, the switch internal contacts close completing the circuit to the brakelights.
A circular, metal clip is used to secure the switch to the bracket on the pedal support. The clip has tangs that seat in the threads of the switch plunger barrel.
Fig. 3 Push Rod Attachment At Brake Pedal (XJ)
BRAKE PEDAL INSTALLATION
(1) Install new bushings in pedal. Lubricate bushings and pivot pin with Mopar multi mileage grease.
(2) Position pedal, sleeve and spacer(s) in bracket and install pivot pin.
(3) Install new nut on pivot pin. Pivot pin nut is specially formed and should not be reused. Be sure to install new nut to secure pin.
(4) ) Tighten new pivot pin nut to 27 N z m (20 ft.
lbs.) on models with manual transmission. Tighten nut to 35 N z m (26 ft. lbs.) on models with automatic transmission.
(5) Install booster push rod on pedal pin (Fig. 3).
Secure push rod with original, or new retainer clip if necessary.
(6) Install dash brace rod, if equipped.
(7) Check and adjust brakelight switch if necessary. Refer to procedure in this section.
BRAKELIGHT SWITCH REMOVAL
The brakelight switch is mounted in the pedal support bracket and is operated by the pedal. The switch is secured in the bracket with a retainer (Fig. 4).
(1) Remove steering column cover and lower trim panel for switch access, if necessary.
(2) Disconnect switch wires.
(3) Thread switch out of retainer, or rock switch up/down and pull it rearward out of retainer.
(4) Inspect switch retainer. Replace retainer if worn, distorted, loose, or damaged.
Fig. 4 Brakelight Switch Mounting And Location
(XJ/YJ)
SWITCH ADJUSTMENT PROCEDURE
(1) Check switch adjustment. Move the brake pedal forward by hand and note operation of the switch plunger. Plunger should be fully extended when pedal free play is taken up and brake application begins. A clearance of approximately 3 mm (1/8 in.) should exist between plunger and pedal at this point.
(a) If switch-to-pedal clearance is OK and brakelights operate correctly, adjustment is not required.
(b) If switch plunger does not fully extend and clearance between pedal and switch barrel is insufficient, adjust switch position as described in step
(2).
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SPECIFICATIONS 5 - 67
(2) Grasp brake pedal and pull it rearward as far as possible. Switch plunger barrel will ‘‘ratchet’’ rearward in retaining clip to correct position.
(3) Verify brakelight switch operation and proper clearance between switch plunger and brake pedal.
CAUTION: Be very sure the brake pedal returns to a fully released position after adjustment. The switch can interfere with full pedal return if too far forward.
The result will be brake drag caused by partial brake application.
SPECIFICATIONS
BRAKE TORQUE SPECIFICATIONS
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CLUTCH 6 - 1
CLUTCH
CONTENTS page
CLUTCH DIAGNOSIS
. . . . . . . . . . . . . . . . . . . . . 3
CLUTCH SERVICE
. . . . . . . . . . . . . . . . . . . . . . 10
page
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1
GENERAL INFORMATION
INDEX
page
Clutch Component Lubrication
. . . . . . . . . . . . . . . . 1
Clutch Components
. . . . . . . . . . . . . . . . . . . . . . . . 1
page
Clutch Linkage Fluid
. . . . . . . . . . . . . . . . . . . . . . . 1
Clutch Operation
. . . . . . . . . . . . . . . . . . . . . . . . . . 2
CLUTCH COMPONENTS
MECHANICAL COMPONENTS
The clutch mechanism in XJ/YJ models with manual transmission consists of a single, dry-type clutch disc and a diaphragm style clutch cover. A hydraulic linkage is used to operate the clutch disc and cover.
The transmission input shaft is supported in the crankshaft by a bearing. A sleeve type release bearing is used to engage and disengage the clutch cover pressure plate.
The release bearing is operated by a release fork in the clutch housing. The fork pivots on a ball stud mounted inside the housing. The release fork is actuated by a hydraulic slave cylinder mounted in the housing. The slave cylinder is operated by a clutch master cylinder mounted on the dash panel. The cylinder push rod is connected to the clutch pedal.
The clutch disc has cushion springs in the disc hub.
The clutch disc facing is riveted to the hub. The facing is made from a non-asbestos material. The clutch cover pressure plate is a diaphragm type with a onepiece spring and multiple release fingers. The pressure plate release fingers are preset during manufacture and are not adjustable.
HYDRAULIC LINKAGE COMPONENTS
The hydraulic linkage consists of a clutch master cylinder with integral reservoir, a clutch slave cylinder and an interconnecting fluid line.
The clutch master cylinder push rod is connected to the clutch pedal. The slave cylinder push rod is connected to the clutch release fork. The master cylinder is mounted on the driver side of the dash panel adjacent to the brake master cylinder and booster assembly. This positioning is similar for both left and right hand drive models.
CLUTCH LINKAGE FLUID
The integral clutch master cylinder reservoir, slave cylinder and fluid lines are prefilled with fluid prior to assembly operations.
The hydraulic system should not require additional fluid under normal circumstances. In fact, the reser- voir fluid level will actually increase as normal clutch wear occurs. For this reason, it is important to avoid overfilling, or removing fluid from the reservoir.
If inspection or diagnosis indicates additional fluid may be needed, use Mopar brake fluid, or an equivalent meeting standards SAE J1703 and DOT 3. Do not use any other type of fluid.
CLUTCH COMPONENT LUBRICATION
Proper clutch component lubrication is important to satisfactory operation. Using the correct lubricant and not overlubricating are equally important. Apply recommended lubricant sparingly to avoid disc and pressure plate contamination.
Clutch and transmission components requiring lubrication are:
• pilot bearing
• release lever pivot ball stud
• release lever contact surfaces
• release bearing bore
• clutch disc hub splines
• clutch pedal pivot shaft bore
• clutch pedal bushings
• input shaft splines
6 - 2 CLUTCH
J
• input shaft pilot hub
• transmission front bearing retainer slide surface
Never apply grease to any part of the clutch cover, or disc.
RECOMMENDED LUBRICANTS
Use Mopar multi-purpose grease for the clutch pedal bushings and pivot shaft. Use Mopar high temperature grease (or equivalent) for all other lubrication requirements. Apply recommended amounts and do not overlubricate.
CLUTCH OPERATION
Leverage, spring force and friction are what make the clutch work. The disc serves as the friction element. The diaphragm spring acting on the pressure plate provides the apply (or clamping) force. And the pedal, hydraulic linkage, release lever and bearing provide the leverage.
The clutch cover, which is bolted to the flywheel, is the component that clamps the disc against the flywheel. The cover is actually an assembly consisting of the cover, diaphragm spring, pressure plate, and fulcrum components.
It is the clutch cover pressure plate that actually clamps the clutch disc against the flywheel. Pressure plate force is supplied by the diaphragm spring.
The disc has a splined hub for installation on the transmission input shaft splines. The splined hub is what connects the disc to the transmission.
The clutch linkage uses hydraulic pressure to operate the clutch. The clutch master cylinder is connected to the clutch pedal and the slave cylinder is connected to the release lever. In operation, pressing the clutch pedal develops fluid pressure in the clutch master cylinder. This pressure is then transmitted directly to the slave cylinder via the connecting line.
In turn, the slave cylinder operates the clutch release lever.
The clutch release bearing is mounted on the transmission front bearing retainer. The bearing is attached to the release lever which moves the bearing in and out of contact with the diaphragm spring.
In operation, slave cylinder force causes the release lever to pivot toward the clutch. This action moves the release bearing into direct contact with the diaphragm spring fingers. As additional force is applied, the release bearing pushes the spring fingers inward relieving spring force on the pressure plate. At this point, the clutch disc is disengaged and freewheeling.
The process of clutch re-engagement, is simply the reverse of what occurs during disengagement. Releasing pedal pressure removes linkage pressure. The release bearing moves away from the spring which again applies clamping force on the disc through the pressure plate.
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CLUTCH DIAGNOSIS 6 - 3
CLUTCH DIAGNOSIS page
Clutch Problem Causes
. . . . . . . . . . . . . . . . . . . . . 3
General Diagnosis Information
. . . . . . . . . . . . . . . . 3
INDEX
page
Inspection and Diagnosis Charts
GENERAL DIAGNOSIS INFORMATION
Unless the cause of a clutch problem is obvious, accurate problem diagnosis will usually require a road test to confirm a problem. Component inspection will then be required to determine the actual problem cause.
During a road test, drive the vehicle at normal speeds. Shift the transmission through all gear ranges and observe clutch action. If chatter, grab, slip, or improper release is experienced, remove and inspect the clutch components. However, if the problem is noise or hard shifting, further diagnosis may be needed as the transmission or another driveline component may be at fault. Careful observation during the test will help narrow the problem area.
CLUTCH PROBLEM CAUSES
CONTAMINATION
Fluid contamination is a frequent cause of clutch malfunctions. Oil, water, or clutch fluid on the clutch contact surfaces will cause faulty operation. The usual result is chatter, slip and grab.
During inspection, note if any components are contaminated with oil, hydraulic fluid, or water/road splash.
Oil contamination indicates a leak at either the rear main seal or transmission input shaft. Oil leakage produces a residue of oil on the housing interior and on the clutch cover and flywheel. Heat buildup caused by slippage between the cover, disc and flywheel, can sometimes bake the oil residue onto the components. The glaze-like residue ranges in color from amber to black.
Road splash contamination means dirt/water is entering the clutch housing due to loose bolts, housing cracks, or through hydraulic line openings. Driving through deep water puddles can force water/road splash into the housing through such openings.
Clutch fluid leaks are from loose or damaged slave cylinder fluid lines and connecting fittings. However, clutch fluid leaks will usually be noted and corrected before severe contamination occurs.
CLUTCH MISALIGNMENT
Clutch components must be in proper alignment with the crankshaft and transmission input shaft.
Misalignment caused by excessive runout or warpage of any clutch component will cause grab, chatter and improper clutch release.
Flywheel Runout
Check flywheel runout whenever misalignment is suspected. Flywheel runout should not exceed 0.08
mm (0.003 in.). Measure runout at the outer edge of the flywheel face with a dial indicator. Mount the indicator on a stud installed in place of one of the flywheel bolts.
Common causes of runout are:
• heat warpage
• improper machining
• incorrect bolt tightening
• improper seating on crankshaft flange shoulder
• foreign material on crankshaft flange
Flywheel machining is not recommended. The flywheel clutch surface is machined to a unique contour and machining will negate this feature. However, minor flywheel scoring can be cleaned up by hand with 180 grit emery, or with surface grinding equipment. Remove only enough material to reduce scoring (approximately 0.001 - 0.003 in.). Heavy stock removal is not recommended. Replace the flywheel if scoring is severe and deeper than 0.076 mm (0.003
in.). Excessive stock removal can result in flywheel cracking or warpage after installation; it can also weaken the flywheel and interfere with proper clutch release.
Clean the crankshaft flange before mounting the flywheel. Dirt and grease on the flange surface may cock the flywheel causing excessive runout. Use new bolts when remounting a flywheel and secure the bolts with Mopar Lock And Seal. Tighten flywheel bolts to specified torque only. Overtightening can distort the flywheel hub causing runout.
Clutch Cover And Disc Runout
Check the clutch disc before installation. Axial
(face) runout of a new disc should not exceed 0.50
mm (0.020 in.). Measure runout about 6 mm (1/4 in.) from the outer edge of the disc facing. Obtain another disc if runout is excessive.
Check condition of the clutch before installation. A warped cover or diaphragm spring will cause grab and incomplete release or engagement. Be careful
6 - 4 CLUTCH DIAGNOSIS
J when handling the cover and disc. Impact can distort the cover, diaphragm spring, release fingers and the hub of the clutch disc.
Use an alignment tool when positioning the disc on the flywheel. The tool prevents accidental misalignment which could result in cover distortion and disc damage.
A frequent cause of clutch cover distortion (and consequent misalignment) is improper bolt tightening. To avoid warping the cover, the bolts must tightened alternately (diagonal pattern) and evenly (2-3 threads at a time) to specified torque.
Clutch Housing Misalignment
Clutch housing alignment is important to proper clutch operation. The housing maintains alignment between the crankshaft and transmission input shaft.
Misalignment can cause clutch noise, hard shifting, incomplete release and chatter. It can also result in premature wear of the pilot bearing, cover release fingers and clutch disc. In severe cases, misalignment can also cause premature wear of the transmission input shaft and shaft bearing.
Housing misalignment is generally caused by incorrect seating on the engine or transmission, loose housing bolts, missing alignment dowels or housing damage. Infrequently, misalignment may also be caused by housing mounting surfaces that are not completely parallel. Misalignment can be corrected with shims.
INSTALLATION METHODS AND PARTS
USAGE
Distortion of clutch components during installation and the use of non-standard components are additional causes of clutch malfunction.
Improper clutch cover bolt tightening can distort the cover. The usual result is clutch grab, chatter and rapid wear. Tighten the cover bolts as described in Clutch Service section.
An improperly seated flywheel and/or clutch housing are additional causes of clutch failure. Improper seating will produce misalignment and additional clutch problems.
The use of non-standard or low quality parts will also lead to problems and wear. Use recommended factory quality parts to avoid comebacks.
INSPECTION AND DIAGNOSIS CHARTS
The clutch inspection chart (Fig. 1) outlines items to be checked before and during clutch installation.
Use the chart as a check list to help avoid overlooking potential problem sources during service operations.
The diagnosis charts describe common clutch problems, causes and correction. Fault conditions are listed at the top of each chart. Conditions, causes and corrective action are outlined in the indicated columns.
The charts are provided as a convenient reference when diagnosing faulty clutch operation.
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CLUTCH DIAGNOSIS 6 - 5
Fig. 1 Clutch Inspection Points
6 - 6 CLUTCH DIAGNOSIS
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CLUTCH DIAGNOSIS 6 - 7
6 - 8 CLUTCH DIAGNOSIS
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CLUTCH DIAGNOSIS 6 - 9
6 - 10 CLUTCH SERVICE
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CLUTCH SERVICE
INDEX
page
Clutch Cover and Disc Installation
Clutch Cover and Disc Removal
Clutch Fluid Level
. . . . . . . . . . . . . . . . . . . . . . . . 14
Clutch Housing Replacement
. . . . . . . . . . . . . . . . 11
Clutch Hydraulic Linkage Installation
Clutch Hydraulic Linkage Removal
page
Clutch Pedal Installation
. . . . . . . . . . . . . . . . . . . 15
Clutch Pedal Removal
. . . . . . . . . . . . . . . . . . . . . 15
Clutch Safety Precautions
. . . . . . . . . . . . . . . . . . 10
Flywheel Service
. . . . . . . . . . . . . . . . . . . . . . . . . 15
Pilot Bearing Replacement
. . . . . . . . . . . . . . . . . 11
Release Bearing Replacement
. . . . . . . . . . . . . . . 11
CLUTCH SAFETY PRECAUTIONS
WARNING: EXERCISE CARE WHEN SERVICING
CLUTCH COMPONENTS.
DUST AND DIRT ON
CLUTCH PARTS USE MAY CONTAIN ASBESTOS FI-
BERS. BREATHING EXCESSIVE CONCENTRATIONS
OF THESE FIBERS CAN CAUSE SERIOUS BODILY
HARM. WEAR A RESPIRATOR DURING SERVICE
AND NEVER CLEAN CLUTCH COMPONENTS WITH
COMPRESSED AIR OR WITH A DRY BRUSH. EI-
THER CLEAN THE COMPONENTS WITH A WATER
DAMPENED RAGS OR USE A VACUUM CLEANER
SPECIFICALLY DESIGNED FOR REMOVING ASBES-
TOS FIBERS AND DUST. DO NOT CREATE DUST
BY SANDING A CLUTCH DISC. REPLACE THE DISC
IF THE FRICTION MATERIAL IS DAMAGED OR
CONTAMINATED. DISPOSE OF ALL DUST AND
DIRT CONTAINING ASBESTOS FIBERS IN SEALED
BAGS OR CONTAINERS. THIS WILL HELP MINIMIZE
EXPOSURE TO YOURSELF AND TO OTHERS. FOL-
LOW ALL RECOMMENDED SAFETY PRACTICES
PRESCRIBED BY THE OCCUPATIONAL SAFETY
AND HEALTH ADMINISTRATION (OSHA) AND THE
ENVIRONMENTAL SAFETY AGENCY (EPA), FOR
THE HANDLING AND DISPOSAL OF PRODUCTS
CONTAINING ASBESTOS.
CLUTCH COVER AND DISC REMOVAL
(1) Remove transmission. Refer to procedures in
Group 21.
(2) If original clutch cover will be reinstalled, mark position of cover on flywheel for assembly reference. Use paint or a scriber for this purpose.
(3) If clutch cover is to be replaced, cover bolts can be removed in any sequence. However, if original cover will be reinstalled, loosen cover bolts evenly and in rotation to relieve spring tension equally.
This is necessary avoid warping cover.
(4) Remove cover bolts and remove cover and disc
(Fig. 2).
CLUTCH COVER AND DISC INSTALLATION
(1) Lightly scuff sand flywheel face with 180 grit emery cloth. Then clean surface with a wax and grease remover.
(2) Lubricate pilot bearing with Mopar high temperature bearing grease.
(3) Check runout and free operation of new clutch disc as follows:
(a) Slide disc onto transmission input shaft splines. Disc should slide freely on splines.
(b) Leave disc on shaft and check face runout with dial indicator. Check runout at disc hub and about 6 mm (1/4 in.) from outer edge of facing.
(c) Face runout should not exceed 0.5 mm (0.020
in.). Obtain another clutch disc if runout exceeds this limit.
(4) Position clutch disc on flywheel. Be sure side of disc marked flywheel side is positioned against flywheel (Fig. 2). If disc is not marked, be sure flat side of disc hub is toward flywheel.
(5) Insert clutch alignment tool in clutch disc (Fig.
3).
(6) Insert alignment tool in pilot bearing and position disc on flywheel. Be sure disc hub is positioned correctly. Side of hub marked Flywheel Side should face flywheel (Fig. 2). If disc is not marked, place flat side of disc against flywheel.
(7) Position clutch cover over disc and on flywheel
(Fig. 3).
(8) Install clutch cover bolts finger tight.
(9) Tighten cover bolts evenly and in rotation a few threads at a time. Cover bolts must be tight- ened evenly and to specified torque to avoid distorting cover. Tightening torques are 31 N z m (23 ft. lbs.) on 2.5L engines and 54 N z m (40 ft. lbs.) on
4.0L engines.
(10) Apply light coat of Mopar high temperature bearing grease to pilot bearing hub and splines of transmission input shaft. Do not overlubricate shaft splines. This will result in grease contamination of disc.
(11) Install transmission (Fig. 4). Refer to procedures in Group 21.
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CLUTCH SERVICE 6 - 11
Fig. 2 Clutch Disc Position
Fig. 3 Typical Method Of Aligning Clutch Disc
RELEASE BEARING REPLACEMENT
(1) Remove transmission as described in Group 21.
(2) Disconnect release bearing from release lever and remove bearing (Fig. 5).
(3) Inspect bearing slide surface of transmission front bearing retainer. Replace retainer if slide surface is scored, worn, or cracked.
(4) Inspect release fork and fork pivot. Be sure pivot is secure and in good condition. Be sure fork is not distorted or worn. Replace release fork retainer spring if bent or damaged in any way.
(5) Lubricate crankshaft pilot bearing with Mopar high temperature bearing grease. Apply grease to end of long shank, small diameter flat blade screwdriver. Then insert tool through clutch disc hub to reach bearing.
(6) Lubricate input shaft splines, bearing retainer slide surface, fork pivot and release fork pivot surface with Mopar high temperature grease.
(7) Install new release bearing. Be sure bearing is properly secured to release fork.
(8) Install transmission as described in Group 21.
PILOT BEARING REPLACEMENT
(1) Remove transmission. Refer to Group 21 for procedure.
(2) Remove clutch cover and disc.
(3) Remove pilot bearing. Use internal (blind hole) puller such those as supplied in Snap On Tool Set
CG40CB to remove bearing.
(4) Lubricate new bearing with Mopar high temperature bearing grease.
(5) Start new bearing into crankshaft by hand.
Then seat bearing with clutch alignment tool (Fig.
6).
(6) Lightly scuff sand flywheel surface with 180 grit emery cloth. Then clean surface with wax and grease remover.
(7) Install clutch disc and cover as described in this section.
(8) Install transmission. Refer to Group 21 for procedure.
CLUTCH HOUSING REPLACEMENT
The AX 15 clutch housing is removable and can be replaced when the transmission is out of the vehicle.
The bolts attaching the housing to the transmission case are located inside the housing (Fig. 7). Recommended tightening torque for the clutch housingto-transmission bolts is 38 N z m (28 ft. lbs.).
Be sure the transmission and housing mating surfaces are clean before installing an original, or replacement clutch housing. Dirt/foreign material trapped between the housing and transmission will cause misalignment.
If misalignment is severe enough, the result will be clutch drag, incomplete release and hard shifting.
CLUTCH HYDRAULIC LINKAGE REMOVAL
The clutch master cylinder, slave cylinder and connecting line are serviced as an assembly only. The linkage components cannot be overhauled or serviced separately. The cylinders and connecting line are sealed units. Also note that removal/installation procedures for right and left hand drive models are basically the same.
Only master cylinder location is different.
(1) Raise vehicle.
(2) Remove fasteners attaching slave cylinder to clutch housing.
(3) Remove slave cylinder from clutch housing
(Fig. 8).
(4) Disengage clutch fluid line from body clips.
(5) Lower vehicle.
6 - 12 CLUTCH SERVICE
J
Fig. 4 Manual Transmission Mounting
Fig. 5 Release Bearing Attachment
(6) Verify that cap on clutch master cylinder reservoir is tight. This is necessary to avoid undue spillage during removal.
(7) Remove clutch master cylinder attaching nuts.
Note that one nut is accessible from engine compartment and one nut is accessible from under instrument panel (Figs. 9 and 10).
(8) Remove clip securing clutch master cylinder push rod to pedal and slide push rod off pedal pin.
(9) If pedal pin is equipped with bushing, inspect condition of bushing and replace it if worn or damaged.
(10) Remove clutch hydraulic linkage through engine compartment.
Fig. 6 Pilot Bearing Installation
CLUTCH HYDRAULIC LINKAGE INSTALLATION
(1) Be sure reservoir cover on clutch master cylinder is tight to avoid spills.
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CLUTCH SERVICE 6 - 13
Fig. 7 Clutch Housing Attachment
Fig. 8 Slave Cylinder Attachment
(2) Position clutch linkage components in vehicle.
Work connecting line and slave cylinder downward past engine and adjacent to clutch housing.
Fig. 9 Clutch Master Cylinder And Push Rod
Attachment (Left Hand Drive Models)
(3) Position clutch master cylinder on dash panel
(Fig. 11).
6 - 14 CLUTCH SERVICE
J
Fig. 10 Clutch Master Cylinder Location (Right Hand
Drive Models)
(4) Attach clutch master cylinder push rod to pin on clutch pedal. Secure rod with new clip if necessary.
(5) Install and tighten clutch master cylinder attaching nuts to 23-34 N z m (200-300 in. lbs.) torque.
(6) Raise vehicle.
(7) Insert slave cylinder push rod through clutch housing opening and into release lever. Be sure cap on end of rod is securely engaged in lever. Check this before installing cylinder attaching nuts.
(8) Install and tighten slave cylinder attaching nuts to 23-34 N z m (200-300 in. lbs.) torque.
(9) Secure clutch fluid line in body clips and lower vehicle.
CLUTCH FLUID LEVEL
The clutch fluid reservoir, master cylinder, slave cylinder and fluid lines are prefilled with fluid at the factory during assembly operations.
The hydraulic system should not require additional fluid under normal circumstances. In fact, the reser- voir fluid level will actually increase as normal clutch wear occurs. For this reason, it is important to avoid overfilling, or removing fluid from the reservoir.
If inspection or diagnosis indicates additional fluid may be needed, use Mopar brake fluid, or an equivalent meeting standards SAE J1703 and DOT 3. Do not use any other type of fluid.
Clutch fluid level is checked at the master cylinder reservoir (Fig. 12). An indicator ring is provided either on the side, or interior rim of the reservoir (Fig.
13).
Be sure to wipe the reservoir and cover clean before removing the cover. This will avoid having dirt or foreign material fall into the reservoir during a fluid level check.
Fig. 12 Clutch Master Cylinder Reservoir And Cap
Fig. 11 Clutch Master Cylinder Mounting (Typical)
Fig. 13 Reservoir Fluid Level Indicator Ring
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CLUTCH SERVICE 6 - 15
Fig. 14 Clutch Pedal Mounting (YJ)
CLUTCH PEDAL REMOVAL
(1) Remove instrument panel lower trim cover for extra working clearance.
(2) Remove retainer clip and washers that attach clutch master cylinder push rod to pedal.
(3) On YJ, remove retaining ring securing pedal to pivot shaft (Fig. 14). On XJ, remove nut securing pedal to pivot shaft (Fig. 15).
(4) Move pedal pivot shaft to right and slide pedal off shaft.
CLUTCH PEDAL INSTALLATION
(1) Lubricate clutch pedal pivot shaft and pedal bushings or sleeve with Mopar multi-mileage grease.
(2) Position pedal on pivot shaft and through brace. Secure pedal with washer and retaining ring on YJ, or with washer and nut on XJ.
(3) Install clutch master cylinder push rod on pedal. Secure rod with washer(s) and new cotter pin.
(4) Install instrument panel lower trim cover, if removed.
FLYWHEEL SERVICE
Inspect the flywheel whenever the clutch disc, cover and housing are removed for service. Check condition of the flywheel face, hub, ring gear teeth, and flywheel bolts.
Minor scratches, burrs, or glazing on the flywheel face can be reduced with 180 grit emery cloth. However, the flywheel should be replaced if the disc contact surface is severely scored, heat checked, cracked, or obviously worn.
Flywheel machining is not recommended. The flywheel surface is manufactured with a unique contour
Fig. 15 Clutch Pedal Mounting (XJ) that would be negated by machining. However, cleanup of minor flywheel scoring can be performed by hand with 180 grit emery, or with surface grinding equipment. Replace the flywheel if scoring is deeper than 0.0762 mm (0.003 in.).
Heavy stock removal by grinding is not recom-
mended. Excessive stock removal can result in flywheel cracking or warpage after installation. It can also weaken the flywheel and interfere with proper clutch release.
6 - 16 CLUTCH SERVICE
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Check flywheel runout if misalignment is suspected. Runout should not exceed 0.08 mm (0.003
in.). Measure runout at the outer edge of the flywheel face with a dial indicator. Mount the dial indicator on a stud installed in place of one of the flywheel attaching bolts.
Clean the crankshaft flange before mounting the flywheel. Dirt and grease on the flange surface may cock the flywheel causing excessive runout.
Check condition of the flywheel hub and attaching bolts. Replace the flywheel if the hub exhibits cracks in the area of the attaching bolt holes.
Install new attaching bolts whenever the flywheel is replaced and use Mopar Lock N’ Seal, or Loctite
242 on the replacement bolt threads.
Recommended flywheel bolt torques are:
•
142 N z m (105 ft. lbs.) for 6-cylinder flywheels
•
68 N z m (50 ft. lbs.) plus an additional turn of 60° for 4-cylinder flywheels
Inspect the teeth on the starter ring gear. If the teeth are worn or damaged, the flywheel should be replaced as an assembly. This is the recommended and preferred method of repair.
In cases where a new flywheel is not readily available, a replacement ring gear can be installed. However, the following precautions must be observed to avoid damaging the flywheel and replacement gear.
(a) Mark position of the old gear for alignment reference on the flywheel. Use a scriber for this purpose.
(b) Wear protective goggles or approved safety glasses. Also wear heat resistent gloves when handling a heated ring gear.
(c) Remove the old gear by cutting most of the way through it (at one point) with an abrasive cutoff wheel. Then complete removal with a cold chisel or punch.
(d) The ring gear is a shrink fit on the flywheel.
This means the gear must be expanded by heating in order to install it. The method of heating and expanding the gear is extremely important.
Every surface of the gear must be heated at the same time to produce uniform expansion. An oven or similar enclosed heating device must be used.
Temperature required for uniform expansion is approximately 375° F.
CAUTION: Do not use an oxy/acetylene torch to remove the old gear, or to heat and expand a new gear. The high temperature of the torch flame can cause localized heating that will damage the flywheel. In addition, using the torch to heat a replacement gear will cause uneven heating and expansion. The torch flame can also anneal the gear teeth resulting in rapid wear and damage after installation.
(e) The heated gear must be installed evenly to avoid misalignment or distortion. A shop press and suitable press plates should be used to install the gear if at all possible.
(f) Be sure to wear eye and hand protection.
Heat resistent gloves and safety goggles are needed for personal safety. Also use metal tongs, vise grips, or similar tools to position the gear as necessary for installation.
(g) Allow the flywheel and ring gear to cool down before installation. Set the assembly on a workbench and let it cool in normal shop air.
CAUTION: Do not use water, or compressed air to cool the flywheel. The rapid cooling produced by water or compressed air can distort, or crack the gear and flywheel.
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TORQUE SPECIFICATIONS
CLUTCH SERVICE 6 - 17
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COOLING SYSTEM 7 - 1
COOLING SYSTEM
CONTENTS page
DIAGNOSIS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
ENGINE ACCESSORY DRIVE BELTS
. . . . . . . . 31
ENGINE BLOCK HEATER
. . . . . . . . . . . . . . . . . 37
page
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1
SERVICE PROCEDURES
. . . . . . . . . . . . . . . . . . . 9
SPECIFICATIONS
. . . . . . . . . . . . . . . . . . . . . . . 38
GENERAL INFORMATION
Throughout this group, references are made to particular vehicle models by alphabetical designation
(XJ or YJ) or by the particular vehicle nameplate. A chart showing a breakdown of alphabetical designations is included in the Introduction section at the beginning of this manual.
of cooling fins. XJ models equipped with a 4.0L 6 cylinder engine and heavy duty cooling and/or air conditioning also have an auxiliary electric cooling fan.
COOLING SYSTEM
The cooling system regulates engine operating temperature. It allows the engine to reach normal operating temperature as quickly as possible, maintains normal operating temperature and prevents overheating.
The cooling system also provides a means of heating the passenger compartment and cooling the automatic transmission fluid (if equipped). The cooling system is pressurized and uses a centrifugal water pump to circulate coolant throughout the system.
An optional factory installed heavy duty cooling package is available on most models. The package consists of a radiator that has an increased number
COOLING SYSTEM COMPONENTS
The cooling system consists of:
• A radiator
• Cooling fan (mechanical and/or electrical)
• Thermal viscous fan drive
• Fan shroud
• Radiator pressure cap
• Thermostat
• Coolant reserve/overflow system
• Transmission oil cooler (if equipped with an automatic transmission)
• Coolant
• Water pump
• Hoses and hose clamps
SYSTEM COOLANT ROUTING
For cooling system flow routings, refer to Figs. 1, 2,
3 or 4.
7 - 2 COOLING SYSTEM
Fig. 1 Coolant Flow—XJ Models with 2.5L Engine—Typical
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Fig. 2 Coolant Flow—YJ Models with 2.5L Engine—Typical
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COOLING SYSTEM 7 - 3
Fig. 3 Coolant Flow—XJ Models with 4.0L
Engine—Typical
Fig. 4 Coolant Flow—YJ Models with 4.0L
Engine—Typical
7 - 4 COOLING SYSTEM
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DIAGNOSIS page
DRB Scan Tool
. . . . . . . . . . . . . . . . . . . . . . . . . . . 5
On-Board Diagnostics (OBD)
. . . . . . . . . . . . . . . . . 4
INDEX
page
Preliminary Checks
. . . . . . . . . . . . . . . . . . . . . . . . 5
ON-BOARD DIAGNOSTICS (OBD)
FOR COOLING SYSTEM COMPONENTS
The powertrain control module (PCM) has been programmed to monitor the certain following cooling system components:
• If the engine has remained cool for too long a period, such as with a stuck open thermostat, a Diagnostic Trouble Code (DTC) number 17 can be observed at the Check Engine Lamp.
• If an open or shorted condition has developed in the relay circuit controlling the electric radiator fan, a Diagnostic Trouble Code (DTC) number 35 can be observed at the Check Engine Lamp.
If the problem is sensed in a monitored circuit often enough to indicate an actual problem, a DTC is stored. The DTC will be stored in the PCM memory for eventual display to the service technician. If the problem is repaired or ceases to exist, the PCM cancels the DTC after 51 engine starts.
Certain criteria must be met for a DTC to be entered into PCM memory. The criteria may be a specific range of engine rpm, engine temperature and/or input voltage to the PCM.
A DTC indicates that the PCM has recognized an abnormal signal in a circuit or the system. A DTC may indicate the result of a failure, but never identify the failed component directly.
It is possible that a DTC for a monitored circuit may not be entered into memory even though a malfunction has occurred. Refer to On-Board Diagnostics
(OBD) in Group 14, Fuel Systems for additional information.
ACCESSING DIAGNOSTIC TROUBLE CODES
A stored Diagnostic Trouble Code (DTC) can be displayed by cycling the ignition key On-Off-On-Off-On within three seconds and observing the Malfunction
Indicator Lamp. This lamp was formerly referred to as the Check Engine Lamp. The lamp is located on the instrument panel.
They can also be displayed through the use of the
Diagnostic Readout Box (DRB) scan tool. The DRB connects to the data link connector in the engine compartment (Figs. 5 or 6). For operation of the
DRB, refer to the appropriate Powertrain Diagnostic
Procedures service manual.
Fig. 5 Data Link Connector—YJ Models—Typical
Fig. 6 Data Link Connector—XJ Models—Typical
EXAMPLES:
• If the lamp flashes 1 time, pauses and flashes 7 more times, a flashing Diagnostic Trouble Code
(DTC) number 17 is indicated.
• If the lamp flashes 3 times, pauses and flashes 5 more times, a flashing Diagnostic Trouble Code
(DTC) number 35 is indicated.
After any stored DTC information has been observed, the display will end with a flashing DTC number 55. This will indicate the end of all stored information.
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COOLING SYSTEM 7 - 5
ERASING TROUBLE CODES
After the problem has been repaired, the DRB scan tool must be used to erase a DTC. Refer to the appropriate Powertrain Diagnostic Procedures service manual for operation of the DRB scan tool.
DRB SCAN TOOL
For operation of the DRB scan tool, refer to the appropriate Powertrain Diagnostic Procedures service manual.
PRELIMINARY CHECKS
ENGINE COOLING SYSTEM OVERHEATING
Establish what driving conditions caused the complaint. Abnormal loads on the cooling system such as the following may be the cause.
1. PROLONGED IDLE, VERY HIGH AMBI-
ENT TEMPERATURE, SLIGHT TAIL WIND AT
IDLE, SLOW TRAFFIC, TRAFFIC JAMS, HIGH
SPEED, OR STEEP GRADES:
Driving techniques that avoid overheating are:
• Idle with A/C off when temperature gauge is at end of normal range.
• Increasing engine speed for more air flow is recommended.
2. TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
3. AIR CONDITIONING; ADD-ON OR AFTER
MARKET:
A maximum cooling package should have been ordered with vehicle if add-on or after market A/C is installed. If not, maximum cooling system components should be installed for model involved per manufacturer’s specifications.
4. RECENT SERVICE OR ACCIDENT RE-
PAIR:
Determine if any recent service has been performed on vehicle that may effect cooling system. This may be:
• Engine adjustments (incorrect timing)
•
Slipping engine accessory drive belt(s)
•
Brakes (possibly dragging)
•
Changed parts (incorrect water pump rotating in wrong direction)
• Reconditioned radiator or cooling system refilling
(possibly under-filled or air trapped in system).
If investigation reveals none of the above as a cause for engine overheating complaint, refer to following Symptom and Action chart.
7 - 6 COOLING SYSTEM
SYMPTOM AND ACTION—SEE PRELIMINARY CHECKS FIRST
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SYSTEM DIAGNOSIS
COOLING SYSTEM 7 - 7
7 - 8 COOLING SYSTEM
SYSTEM DIAGNOSIS (CONT.)
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COOLING SYSTEM 7 - 9
SERVICE PROCEDURES
INDEX
page
Coolant
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Coolant Reserve/Overflow System
Cooling System Cleaning/Reverse Flushing
Cooling System Fans
. . . . . . . . . . . . . . . . . . . . . 26
Cooling System Hoses
. . . . . . . . . . . . . . . . . . . . 26
Draining Cooling System
. . . . . . . . . . . . . . . . . . . 16
Radiator Pressure Cap
. . . . . . . . . . . . . . . . . . . . 20
Radiators
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
page
Refilling Cooling System
. . . . . . . . . . . . . . . . . . . 17
Testing Cooling System for Leaks
Thermostat
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Transmission Oil Coolers
. . . . . . . . . . . . . . . . . . . 29
Water Pump Tests
. . . . . . . . . . . . . . . . . . . . . . . . 9
Water Pumps—General Information
Water Pumps—Removal/Installation
WATER PUMPS—GENERAL INFORMATION
A centrifugal water pump circulates coolant through the water jackets, passages, intake manifold, radiator core, cooling system hoses and heater core.
The pump is driven from the engine crankshaft by a drive belt on all engines.
The water pump impeller is pressed onto the rear of a shaft that rotates in bearings pressed into the housing. The housing has a small hole to allow seepage to escape. The water pump seals are lubricated by the antifreeze in the coolant mixture. No additional lubrication is necessary.
CAUTION: All engines are equipped with a reverse
(counter-clockwise) rotating water pump and viscous fan drive assembly. REVERSE is stamped or imprinted on the cover of the viscous fan drive and inner side of the fan. The letter R is stamped into the back of the water pump impeller (Fig. 1).
Fig. 1 Reverse Rotating Water Pump—Typical
Engines from previous model years, depending upon application, may have been equipped with a forward (clockwise) rotating water pump. Installation of the wrong water pump will cause engine overheating.
A quick test to determine if the pump is working is to check if the heater warms properly. A defective water pump will not be able to circulate heated coolant through the long heater hose to the heater core.
WATER PUMP TESTS
LOOSE IMPELLER
DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM THE COOL-
ANT CAN OCCUR.
(1) Drain the cooling system.
(2) Loosen the fan belt(s).
(3) Disconnect the lower radiator hose from the water pump.
(4) Bend a stiff clothes hanger or welding rod as shown in (Fig. 2).
(5) Position the rod in the water pump inlet and attempt to hold the impeller while turning the fan blades. If equipped with a viscous fan drive, turn the water pump shaft with a breaker bar and socket attached to a mounting flange nut. If the impeller is loose and can be held with the rod while the fan blades are turning, the pump is defective. If the impeller turns, the pump is OK.
Connect the hose and install the coolant, or proceed with repairs.
INSPECTING FOR INLET RESTRICTIONS
Inadequate heater performance may be caused by a metal casting restriction in the water pump heater hose inlet.
7 - 10 COOLING SYSTEM
J
The water pump impeller is pressed on the rear of the pump shaft and bearing assembly. The water pump is serviced only as a complete assembly.
WARNING: DO NOT REMOVE THE BLOCK DRAIN
PLUG(S) OR LOOSEN RADIATOR DRAINCOCK
WITH THE SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
DO NOT WASTE reusable coolant. If the solution is clean, drain coolant into a clean container for reuse.
(1) Disconnect negative battery cable at battery.
(2) Drain the cooling system. Refer to Draining
Cooling System in this group.
(3) XJ models with 4.0L engine equipped with
A/C or heavy duty cooling system:
Loosen (but do not remove at this time) the four water pump pulley-to-water pump hub mounting bolts (Fig. 3).
Fig. 2 Impeller Test—Typical
DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM THE COOL-
ANT CAN OCCUR.
(1) Drain sufficient coolant from the radiator to decrease the level below the water pump heater hose inlet.
(2) Remove the heater hose.
(3) Inspect the inlet for metal casting flash or other restrictions.
Remove the pump from engine before removing restriction to prevent contamination of the coolant with debris. Refer to Water Pump Removal.
WATER PUMPS—REMOVAL/INSTALLATION
REMOVAL—ALL MODELS
The water pump on all models can be removed without discharging the air conditioning system (if equipped).
CAUTION: All engines have a reverse (counterclockwise) rotating water pump. The letter R is stamped into the back of the water pump impeller
(Fig. 1) to identify. Engines from previous model years, depending upon application, may be equipped with a forward (clockwise) rotating water pump. Installation of the wrong water pump will cause engine over heating.
Fig. 3 Water Pump Pulley Bolts
XJ models with 4.0L engine without A/C or heavy duty cooling system; or any 2.5L engines; or any YJ models:
Loosen (but do not remove at this time) the four fan hub-to-water pump pulley mounting nuts (Fig.
4).
The engine accessory drive belt must be removed prior to removing the fan (if installed at pump) or fan pulley.
(4) Remove engine drive belt as follows:
(a) Loosen two rear power steering pump mounting bolts A (Fig. 5).
(b) Loosen upper pump pivot bolt B and lower lock nut C (Figs. 6 or 7).
(c) Loosen pump adjusting bolt D (Fig. 5) until belt can be removed.
(d) Remove belt.
(5) Check condition of all pulleys.
(6) The power steering pump must be removed from its cast mounting bracket to gain access to bolt
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COOLING SYSTEM 7 - 11
Fig. 4 Fan Mounting Nuts Fig. 6 P.S. Pump Front Mounting
Bolt/Locknut—Typical
Fig. 5 P.S. Pump Rear Mounting Bolts—Typical
E. Bracket mounting bolt E is located behind the power steering pump (Fig. 7).
(7) Remove two bolts A (Fig. 5).
(8) Remove locknut C and belt adjustment bolt D
(Figs. 6 or 7).
(9) Remove bolt B (Fig. 6). Position power steering pump to the side. Hold pump in position with wire.
Do not disconnect hydraulic lines from pump.
(10) Remove bolts E, F and G (Fig. 7) and remove pump mounting bracket.
Fig. 7 Bracket Mounting Bolts—Typical
(11) Remove idler pulley mounting bolt and remove idler pulley. This must be done to gain clearance for the water pump mounted heater hose fitting when water pump is being removed. Note position of pulley spacers after removal.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUM-
BER 6094) (FIG. 8). SNAP-ON CLAMP TOOL (NUM-
BER HPC-20) MAY BE USED FOR LARGER
CLAMPS.
ALWAYS WEAR SAFETY GLASSES
WHEN SERVICING CONSTANT TENSION CLAMPS.
7 - 12 COOLING SYSTEM
CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with matching number or letter.
(12) Remove lower radiator hose from water pump.
Remove heater hose from water pump fitting.
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Fig. 8 Hose Clamp Tool—Typical
(13) Remove four nuts or bolts (refer to the previous step #3).
(14) Remove the fan assembly and pulley (if fan is installed at pump), or remove the pulley from the vehicle.
(15) Remove the four pump mounting bolts (Fig. 9) and remove pump from vehicle. Discard old gasket.
Note that one of the four bolts is longer than the other bolts.
(16) If pump is to be replaced, the heater hose fitting must be removed. Note position of fitting before removal.
INSTALLATION—ALL MODELS
(1) If pump is being replaced, install the heater hose fitting to the pump. Use a sealant on the fitting such as Mopar™ Thread Sealant With Teflon. Refer to the directions on the package.
(2) Clean the gasket mating surfaces. If the original pump is used, remove any deposits or other foreign material. Inspect the cylinder block and water pump mating surfaces for erosion or damage from cavitation.
(3) Install the gasket and water pump (the gasket is installed dry). Tighten mounting bolts to 30 N z m
(22 ft. lbs.) torque. Rotate the shaft by hand to be sure it turns freely.
(4) Connect the radiator and heater hoses to the water pump.
(5) Position water pump pulley to water pump hub.
(6) If equipped with a water pump mounted fan, install fan and four nuts to water pump hub. If not
Fig. 9 Water Pump Remove/Install—Typical equipped with a water pump mounted fan, install four pump hub bolts. Tighten bolts (or nuts) to 27
N z m (20 ft. lbs.) torque.
(7) Position power steering pump bracket to engine. Install bolts E, F and G (Fig. 7). Tighten bolts
F and G to 38 N z m (28 ft. lbs.) torque. Tighten bolt E to 27 N z m (20 ft. lbs.) torque.
(8) Position power steering pump to mounting bracket. Install pivot bolt B (Fig. 6) finger tight. Install locknut C and adjustment bolt D (Figs. 6 or 7) finger tight.
(9) Install two adjustment bolts A (Fig. 6) finger tight.
(10) Install idler pulley.
CAUTION: When installing the serpentine engine accessory drive belt, the belt MUST be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction. Refer to
Figs. 10, 11, 12 or 13 for appropriate belt routing.
You may also refer to the Belt Routing Label in the vehicle engine compartment.
(11) Position drive belt to pulleys.
(12) Tighten belt adjustment bolt D (Fig. 5) to the proper tension. Refer to the Specifications section at the end of this group for belt tension.
(13) Tighten bolts A (Fig. 5) to 27 N z m (20 ft. lbs.) torque.
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COOLING SYSTEM 7 - 13
Fig. 10 YJ Models with 4.0L Engine and XJ Models with 2.5L Engine—With A/C
Fig. 12 XJ Models with 4.0L Engine—Without A/C
Fig. 11 YJ Models With 2.5L or 4.0L Engine and XJ
Models with 2.5L Engine—Without A/C
(14) Tighten pivot bolt B (Fig. 6) to 27 N z m (20 ft.
lbs.) torque.
(15) Tighten locknut C (Fig. 6) to 27 N z m (20 ft.
lbs.) torque.
(16) After the power steering pump has been tightened, recheck belt tension.
(17) Fill cooling system with coolant and check for leaks. Refer to Refilling Cooling System in this group.
(18) Connect battery cable to battery.
(19) Start and warm the engine. Check for leaks.
Fig. 13 XJ Models With 4.0L Engine—With A/C
THERMOSTAT
DESCRIPTION AND OPERATION
A pellet-type thermostat controls the operating temperature of the engine by controlling the amount of coolant flow to the radiator. On all engines the thermostat is closed below 195°F (90°C). Above this temperature, coolant is allowed to flow to the radiator. This provides quick engine warmup and overall temperature control.
An arrow plus the word UP is stamped on the front flange next to the air bleed. The words TO
RAD are stamped on one arm of the thermostat.
They indicate the proper installed position.
The same thermostat is used for winter and summer seasons. An engine should not be operated without a thermostat, except for servicing or testing.
Operating without a thermostat causes other problems. These are: longer engine warmup time, unreliable warmup performance, increased exhaust emissions and crankcase condensation. This condensation can result in sludge formation.
7 - 14 COOLING SYSTEM
CAUTION: Do not operate an engine without a thermostat, except for servicing or testing.
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ON-BOARD DIAGNOSTICS
XJ and YJ models are equipped with On-Board Diagnostics for certain cooling system components. Refer to On-Board Diagnostics (OBD) in the Diagnosis section of this group for additional information. If the powertrain control module (PCM) detects low engine coolant temperature, it will record a Diagnostic Trouble Code (DTC) in the PCM memory. The DTC number for low coolant temperature is 17. Do not change a thermostat for lack of heat as indicated by the instrument panel gauge or heater performance unless a
DTC number 17 is present. Refer to the Diagnosis section of this group for other probable causes. For other DTC numbers, refer to On-Board Diagnostics in the General Diagnosis section of group 14, Fuel
Systems.
The DTC can also be accessed through the DRB scan tool. Refer to the appropriate Powertrain Diagnostic Procedures manual for diagnostic information and operation of the DRB scan tool.
REMOVAL
WARNING: DO NOT LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND PRES-
SURIZED. SERIOUS BURNS FROM THE COOLANT
CAN OCCUR.
DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
(1) Drain the coolant from the radiator until the level is below the thermostat housing.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUM-
BER 6094) (FIG. 14). SNAP-ON CLAMP TOOL (NUM-
BER HPC-20) MAY BE USED FOR LARGER
CLAMPS.
ALWAYS WEAR SAFETY GLASSES
WHEN SERVICING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with matching number or letter.
(2) Remove radiator upper hose and heater hose at thermostat housing.
(3) Disconnect wiring connector at engine coolant temperature sensor.
Fig. 14 Hose Clamp Tool—Typical
(4) Remove thermostat housing mounting bolts, thermostat housing, gasket and thermostat (Fig. 15).
Discard old gasket.
Fig. 15 Thermostat Removal/Installation
(5) Clean the gasket mating surfaces.
INSTALLATION
(1) Install the replacement thermostat so that the pellet, which is encircled by a coil spring, faces the engine. All thermostats are marked on the outer flange to indicate the proper installed position.
(a) Observe the recess groove in the engine cylinder head (Fig. 16).
(b) Position thermostat in groove with arrow and air bleed hole on outer flange pointing up.
(2) Install replacement gasket and thermostat housing.
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COOLING SYSTEM 7 - 15
pose of heat transfer only. Water also freezes at a higher temperature and allows corrosion.
100 percent Ethylene-Glycol-The corrosion inhibiting additives in ethylene-glycol need the presence of water to dissolve. Without water, additives form deposits in system. These act as insulation causing temperature to rise to as high as 149°C (300°F). This temperature is hot enough to melt plastic and soften solder. The increased temperature can result in engine detonation. In addition, 100 percent ethyleneglycol freezes at -22°C (-8°F).
50/50 Ethylene-Glycol and Water-Is the recommended mixture, it provides protection against freezing to -37°C (-35°F). The antifreeze concentration
must always be a minimum of 44 percent, yearround in all climates. If percentage is lower, engine parts may be eroded by cavitation. Maximum protection against freezing is provided with a 68 percent antifreeze concentration, which prevents freezing down to -67.7°C (-90°F). A higher percentage will freeze at a warmer temperature. Also, a higher percentage of antifreeze can cause the engine to overheat because specific heat of antifreeze is lower than that of water.
CAUTION: Richer antifreeze mixtures cannot be measured with normal field equipment and can cause problems associated with 100 percent ethylene-glycol.
Fig. 16 Thermostat Recess
CAUTION: Tightening the thermostat housing unevenly or with the thermostat out of its recess, may result in a cracked housing.
(3) Tighten the housing bolts to 20 N z m (15 ft. lbs.) torque.
(4) Install hoses to thermostat housing.
(5) Install electrical connector to coolant temperature sensor.
(6) Be sure that the radiator draincock is tightly closed. Fill the cooling system to the correct level with the required coolant mixture. Refer to Refilling
Cooling System in this group.
(7) Start and warm the engine. Check for leaks.
COOLANT
GENERAL INFORMATION
The cooling system is designed around the coolant.
Coolant flows through the engine water jackets absorbing heat produced during engine operation. The coolant carries heat to the radiator and heater core.
Here it is transferred to the ambient air passing through the radiator and heater core fins. The coolant also removes heat from the automatic transmission fluid in vehicles equipped with an automatic transmission.
COOLANT PERFORMANCE
The required ethylene-glycol (antifreeze) and water mixture depends upon climate and vehicle operating conditions. The coolant performance of various mixtures follows:
Pure Water-Water can absorb more heat than a mixture of water and ethylene-glycol. This is for pur-
COOLANT SELECTION-ADDITIVES
Coolant should be maintained at the specified level with a mixture of ethylene glycol-based antifreeze and low mineral content water. Only use an antifreeze containing ALUGARD 340-2 ™.
CAUTION: Do not use coolant additives that are claimed to improve engine cooling.
COOLANT SERVICE
It is recommended that the cooling system be drained and flushed at 84,000 kilometers (52,500 miles), or 3 years, whichever occurs first. Then every two years, or 48,000 kilometers (30,000 miles), whichever occurs first.
COOLANT LEVEL CHECK—ROUTINE
Do not remove radiator cap for routine coolant level inspections. The coolant level can be checked at coolant reserve/overflow tank.
The coolant reserve/overflow system provides a quick visual method for determining coolant level without removing radiator pressure cap. With engine idling and at normal operating temperature, observe coolant level in reserve/overflow tank. The coolant level should be between ADD and FULL marks.
7 - 16 COOLING SYSTEM
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ADDING ADDITIONAL COOLANT—ROUTINE
Do not remove radiator cap to add coolant to
system. When adding coolant to maintain correct level, do so at coolant reserve/overflow tank. Use a
50/50 mixture of ethylene-glycol antifreeze containing Alugard 340-2 ™ and low mineral content water.
Remove radiator cap only for testing or when refilling system after service. Removing cap unnecessarily can cause loss of coolant and allow air to enter system, which produces corrosion.
COOLANT LEVEL CHECK-SERVICE
The cooling system is closed and designed to maintain coolant level to top of radiator.
WARNING: DO NOT OPEN RADIATOR DRAINCOCK
WITH ENGINE RUNNING OR WHILE ENGINE IS HOT
AND COOLING SYSTEM IS UNDER PRESSURE.
When vehicle servicing requires a coolant level check in radiator, drain several ounces of coolant from radiator drain cock. Do this while observing coolant reserve/overflow system tank. The coolant level in reserve/overflow tank should drop slightly. If not, inspect for a leak between radiator and coolant reserve/overflow system connection. Remove radiator cap. The coolant level should be to top of radiator. If not and if coolant level in reserve/overflow tank is at
ADD mark, check for:
•
An air leak in coolant reserve/overflow tank or its hose
• An air leak in radiator filler neck
• Leak in pressure cap seal to radiator filler neck
LOW COOLANT LEVEL-AERATION
If the coolant level in radiator drops below top of radiator core tubes, air will enter cooling system.
Low coolant level can cause thermostat pellet to be suspended in air instead of coolant. This will cause thermostat to open later, which in turn causes higher coolant temperature. Air trapped in cooling system also reduces amount of coolant circulating in heater core resulting in low heat output.
DEAERATION
As the engine operates, any air trapped in cooling system gathers under the radiator cap. The next time the engine is operated, thermal expansion of coolant will push any trapped air past radiator cap into the coolant reserve/overflow tank. Here it escapes to the atmosphere into the tank. When the engine cools down the coolant, it will be drawn from the reserve/ overflow tank into the radiator to replace any removed air.
DRAINING COOLING SYSTEM
ALL MODELS—EXCEPT XJ WITH 4.0L ENGINE
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM COOLANT
CAN OCCUR.
DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
DO NOT remove the radiator cap when draining the coolant from the reserve/overflow tank. Open the radiator draincock and when the tank is empty, remove the radiator cap. The coolant does not have to be removed from the tank unless the system is being refilled with a fresh mixture.
(1) Drain the coolant from the radiator by loosening the draincock.
(2) Drain coolant from engine as follows:
(a) On 2.5L engines (all models) by removing drain plug at left rear side of block.
(b) On 4.0L engines by removing the drain plug or coolant temperature sensor on the left side of the block (Fig. 17).
Fig. 17 Draining Coolant—4.0L Engine
XJ MODELS WITH 4.0L ENGINE
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM COOLANT
CAN OCCUR.
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COOLING SYSTEM 7 - 17
DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
(1) Remove radiator pressure cap.
(2) For access to radiator draincock, remove radiator grille (Fig. 18).
XJ MODELS
(1) Tighten the radiator draincock and the cylinder block drain plug(s). If removed, install coolant temperature sensor (4.0L engine).
(2) Fill system using a 50/50 mixture of water and antifreeze as described in the Coolant section of this group. Fill radiator to top and install radiator cap.
Add sufficient coolant to reserve/overflow tank to raise level to FULL mark.
(3) With heater control unit in the HEAT position, operate engine with radiator cap in place.
(4) After engine has reached normal operating temperature, shut engine off and allow it to cool.
(5) Add coolant to reserve/overflow tank as necessary. Only add coolant when the engine is cold.
Coolant level in a warm engine will be higher due to thermal expansion.
COOLING SYSTEM CLEANING/REVERSE FLUSHING
CAUTION: The cooling system normally operates at
97-to-124 kPa (14-to-18 psi) pressure. Exceeding this pressure may damage the radiator or hoses.
Fig. 18 Draincock Access—XJ Models with 4.0L
Engine
(3) Attach one end of a 24 inch long X 1/4 inch ID hose to the radiator draincock. Put the other end into a clean container. Open draincock and drain coolant from radiator.
(4) Drain coolant from engine by removing the drain plug and coolant temperature sensor on left side of block (Fig. 17).
REFILLING COOLING SYSTEM
YJ MODELS
(1) Remove draining hose. Tighten the radiator draincock and the cylinder block drain plug(s).
(2) Fill system using a 50/50 mixture of water and antifreeze. This is described in the Coolant section of this group. Fill the radiator to the top and install the radiator cap. Add sufficient coolant to the reserve/ overflow tank to raise the level to the FULL mark.
(3) Operate the engine with the radiator cap and reserve/overflow tank cap in place. After the engine has reached the normal operating temperature, shut the engine off and allow it to cool.
(4) Add coolant to the reserve/overflow tank as necessary. Only add coolant when the engine is cold. Coolant level in a warm engine will be higher due to thermal expansion.
CLEANING
Drain cooling system and refill with water. Run engine with radiator cap installed until upper radiator hose is hot. Stop engine and drain water from system. If water is dirty, fill system with water, run engine and drain system. Repeat until water drains clean.
REVERSE FLUSHING
Reverse flushing of the cooling system is the forcing of water through the cooling system. This is done using air pressure in the opposite direction of normal coolant flow. It is usually only necessary with very dirty systems with evidence of partial plugging.
REVERSE FLUSHING RADIATOR
Disconnect the radiator hoses from the radiator fittings. Attach a section of radiator hose to the radiator bottom outlet fitting and insert the flushing gun.
Connect a water supply hose and air supply hose to the flushing gun.
CAUTION: The cooling system normally operates at
97-to-124 kPa (14-to-18 psi) pressure. Exceeding this pressure may damage the radiator or hoses.
Allow the radiator to fill with water. When radiator is filled, apply air in short blasts allowing radiator to refill between blasts. Continue this reverse flushing until clean water flows out through rear of radiator cooling tube passages. For more information, refer to operating instructions supplied with flushing equipment. Have radiator cleaned more extensively by a radiator repair shop.
7 - 18 COOLING SYSTEM
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REVERSE FLUSHING ENGINE
Drain the cooling system. Remove the thermostat housing and thermostat. Install the thermostat housing. Disconnect the radiator upper hose from the radiator and attach the flushing gun to the hose.
Disconnect the radiator lower hose from the water pump. Attach a lead away hose to the water pump inlet fitting.
CAUTION: On XJ models, be sure that the heater control valve is closed (heat off). This is done to prevent coolant flow with scale and other deposits from entering the heater core.
Connect the water supply hose and air supply hose to the flushing gun. Allow the engine to fill with water. When the engine is filled, apply air in short blasts, allowing the system to fill between air blasts.
Continue until clean water flows through the lead away hose. For more information, refer to operating instructions supplied with flushing equipment.
Remove the lead away hose, flushing gun, water supply hose and air supply hose. Remove the thermostat housing and install thermostat. Install the thermostat housing with a replacement gasket. Refer to
Thermostat Replacement. Connect the radiator hoses.
Refill the cooling system with the correct antifreeze/ water mixture.
CHEMICAL CLEANING
In some instances, use a radiator cleaner (Mopar
Radiator Kleen or equivalent) before flushing. This will soften scale and other deposits and aid the flushing operation.
CAUTION: Be sure instructions on the container are followed.
TESTING COOLING SYSTEM FOR LEAKS
ULTRAVIOLET LIGHT METHOD
All Jeep™ models have a leak detection additive added to the cooling system before they leave the factory. The additive is highly visible under ultraviolet light (black light). If the factory original coolant has been drained, pour one ounce of additive into the cooling system. The additive is available through the part’s department. Place the heater control unit in
HEAT position. Start and operate the engine until the radiator upper hose is warm to the touch. Aim the black light (tool 7138 or an equivalent), at the components to be checked. If leaks are present, the black light will cause the additive to glow a bright green color.
The black light can be used along with a pressure tester to determine if any external leaks exist (Fig.
19).
Fig. 19 Leak Detection Using Black Light—Typical
PRESSURE TESTER METHOD
The engine should be at the normal operating temperature. Recheck the system cold if the cause of coolant loss is not located during warm engine examination.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING.
Carefully remove the radiator pressure cap from the filler neck and check the coolant level. Push down on the cap to disengage it from the stop tabs.
Wipe the inner part of the filler neck and examine the lower inside sealing seat for nicks, cracks, paint, dirt and solder residue. Inspect the reserve/overflow tank tube for internal obstructions. Insert a wire through the tube to be sure it is not obstructed.
Inspect the cams on the outside part of the filler neck. If the cams are bent, seating of pressure cap valve and tester seal will be affected. Bent cams can be reformed if done carefully. Attach pressure tester
7700 or an equivalent to the radiator filler neck (Fig.
20).
Operate the tester pump to apply 124 kPa (18 psi) pressure to the system. If the hoses enlarge excessively or bulge while testing, replace as necessary.
Observe the gauge pointer and determine the condition of the cooling system according to the following criteria:
• Holds Steady: If the pointer remains steady for two minutes, there are no serious coolant leaks in the system. However, there could be an internal leak that does not appear with normal system test pressure. Inspect for interior leakage or do the Internal
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COOLING SYSTEM 7 - 19
WARNING: DO NOT DISCONNECT THE SPARK
PLUG WIRES WHILE THE ENGINE IS OPERATING.
Fig. 20 Pressurizing System—Typical
Leakage Test. Do this if it is certain that coolant is being lost and no leaks can be detected.
• Drops Slowly: Shows a small leak or seepage is occurring. Examine all connections for seepage or slight leakage with a flashlight. Inspect the radiator, hoses, gasket edges and heater. Seal any small leak holes with a Sealer Lubricant or equivalent. Repair leak holes and reinspect the system with pressure applied.
• Drops Quickly: Shows that a serious leakage is occurring. Examine the system for serious external leakage. If no leaks are visible, inspect for internal leakage. Large radiator leak holes should be repaired by a reputable radiator repair shop.
INTERNAL LEAKAGE INSPECTION
Remove the oil pan drain plug and drain a small amount of engine oil. Coolant, being heavier will drain first, or operate engine to churn oil, then examine dipstick for water globules. Inspect the transmission dipstick for water globules. Inspect the transmission fluid cooler for leakage. Operate the engine without the pressure cap on the radiator until thermostat opens.
Attach a Pressure Tester to the filler neck. If pressure builds up quickly, a leak exists as result of a faulty cylinder head gasket or crack in the engine.
Repair as necessary.
WARNING: DO NOT ALLOW PRESSURE TO EX-
CEED 124 KPA (18 PSI). TURN THE ENGINE OFF.
TO RELEASE THE PRESSURE, ROCK THE TESTER
FROM SIDE TO SIDE. WHEN REMOVING THE
TESTER, DO NOT TURN THE TESTER MORE THAN
1/2 TURN IF THE SYSTEM IS UNDER PRESSURE.
If there is no immediate pressure increase, pump the Pressure Tester until the indicated pressure is within the system range. Vibration of the gauge pointer indicates compression or combustion leakage into the cooling system.
CAUTION: Do not operate the engine with a spark plug shorted for more than a minute. The catalytic converter may be damaged.
Isolate the compression leak by shorting each spark plug to the cylinder block. The gauge pointer should stop or decrease vibration when spark plug for leaking cylinder is shorted. This happens because of the absence of combustion pressure.
COMBUSTION LEAKAGE TEST (WITHOUT
PRESSURE TESTER)
DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM COOLANT
CAN OCCUR.
Drain sufficient coolant to allow for thermostat removal. Refer to Thermostat Replacement. Disconnect the water pump drive belt.
Disconnect the upper radiator hose from the thermostat housing. Remove the housing and thermostat.
Install the thermostat housing.
Add coolant to the radiator to bring the level to within 6.3 mm (1/4 in) of the top of the thermostat housing.
CAUTION: Avoid overheating. Do not operate the engine for an excessive period of time. Open the draincock immediately after the test to eliminate boil over of coolant.
Start the engine and accelerate rapidly three times
(to approximately 3000 rpm) while observing the coolant. If internal engine combustion gases are leaking into the cooling system, bubbles will appear in the coolant. If bubbles do not appear, there is no internal combustion gas leakage.
COOLANT RESERVE/OVERFLOW SYSTEM
The system works along with the radiator pressure cap. This is done by using thermal expansion and contraction of the coolant to keep the coolant free of trapped air. It provides:
• A volume for coolant expansion and contraction.
• A convenient and safe method for checking/adjusting coolant level at atmospheric pressure. This is done without removing the radiator pressure cap.
• Some reserve coolant to cover minor leaks and evaporation or boiling losses.
7 - 20 COOLING SYSTEM
The coolant reserve/overflow system consists of a radiator mounted pressurized cap, a plastic reserve/ overflow tank (Figs. 21, 22 or 23), a tube connecting the radiator and tank, and an overflow tube on the side of the tank.
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Fig. 21 Reserve/Overflow Tank—YJ Models
Fig. 22 Reserve/Overflow Tank—XJ Models—Except
Right Hand Drive
TANK REMOVAL/INSTALLATION
(1) Remove the tube clamp at the tank and remove tube.
Fig. 23 Reserve/Overflow Tank—XJ Models—With
Right Hand Drive
(2) On YJ models, remove the windshield washer reservoir and its mounting bracket.
(3) Remove the tank mounting bolts and remove tank.
(4) Reverse the preceding steps for installation.
RADIATOR PRESSURE CAP
All radiators are equipped with a pressure cap.
This cap releases pressure at some point within a range of 83-110 kPa (12-16 psi). The pressure relief point (in pounds) is engraved on top of the cap (Fig.
24).
The cooling system will operate at pressures slightly above atmospheric pressure. This results in a higher coolant boiling point allowing increased radiator cooling capacity. The cap (Fig. 24) contains a spring-loaded pressure relief valve. This valve opens when system pressure reaches the release range of
83-110 kPa (12-16 psi).
A vent valve in the center of the cap allows a small coolant flow through the cap when coolant is below boiling temperature. The valve is completely closed when boiling point is reached. As coolant cools, it contracts and creates a vacuum in the cooling system. This causes the vacuum valve to open and coolant in reserve/overflow tank to be drawn through connecting hose into radiator. If the vacuum valve is stuck shut, radiator hoses will collapse on cool-down.
A rubber gasket seals the radiator filler neck. This is done to maintain vacuum during coolant cool-down and to prevent leakage when system is under pressure.
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COOLING SYSTEM 7 - 21
TOR UPPER HOSE TO CHECK IF SYSTEM IS UN-
DER PRESSURE. PLACE A RAG OVER THE CAP
AND WITHOUT PUSHING DOWN, ROTATE CAP
COUNTER-CLOCKWISE TO THE FIRST STOP. AL-
LOW FLUID TO ESCAPE THROUGH OVERFLOW
HOSE INTO COOLANT RESERVE/OVERFLOW
TANK. SQUEEZE RADIATOR UPPER HOSE TO DE-
TERMINE WHEN PRESSURE HAS BEEN RE-
LEASED. WHEN COOLANT AND STEAM STOP
BEING PUSHED INTO TANK AND SYSTEM PRES-
SURE DROPS, REMOVE RADIATOR CAP COM-
PLETELY.
PRESSURE TESTING RADIATOR CAPS
Remove cap from radiator. Be sure that sealing surfaces are clean. Moisten rubber gasket with water and install the cap on pressure tester (tool 7700 or an equivalent) (Fig. 25).
Fig. 24 Radiator Pressure Cap
RADIATOR CAP-TO-FILLER NECK
SEAL—PRESSURE RELIEF CHECK
With radiator cap installed on filler neck, remove coolant reserve/ overflow tank hose from nipple on filler neck. Connect a hand operated vacuum pump to nipple. Operate pump until a reading of 47-to-61 kPa (14-to-18 in. Hg) appears on gauge. If the reading stays steady, or drops slightly and then remains steady, the pressure valve seal is good. Replace radiator cap if reading does not hold.
WARNING: THE WARNING WORDS -DO NOT OPEN
HOT- ON THE RADIATOR PRESSURE CAP (FIG. 24)
ARE A SAFETY PRECAUTION. WHEN HOT, PRES-
SURE BUILDS UP IN COOLING SYSTEM. TO PRE-
VENT SCALDING OR INJURY, THE RADIATOR CAP
SHOULD NOT BE REMOVED WHILE THE SYSTEM
IS HOT AND/OR UNDER PRESSURE.
There is no need to remove the radiator cap except for the following purposes:
(1) To check and adjust antifreeze freeze point.
(2) To refill system with new antifreeze.
(3) For conducting service procedures.
(4) When checking for vacuum leaks.
WARNING: IF VEHICLE HAS BEEN RUN RECENTLY,
WAIT AT LEAST 15 MINUTES BEFORE REMOVING
RADIATOR CAP. WITH A RAG, SQUEEZE RADIA-
Fig. 25 Pressure Testing Radiator Pressure Cap
Operate the tester pump and observe the gauge pointer at its highest point. The cap release pressure should be 83-to-110 kPa (12-to-16 psi). The cap is satisfactory when the pressure holds steady. It is also good if it holds pressure within the 83-to-110 kPa
(12-to-16 psi) range for 30 seconds or more. If the pointer drops quickly, replace the cap.
INSPECTION
Visually inspect the pressure valve gasket on the cap. Replace cap if the gasket is swollen, torn or worn. Inspect the area around radiator filler neck for white deposits that indicate a leaking cap.
7 - 22 COOLING SYSTEM
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RADIATORS
GENERAL INFORMATION
All radiators are down flow types except XJ models with 4.0L engines. Radiators in XJ models equipped with the 4.0L six-cylinder engine, are the cross flow type. Plastic tanks are used on all radiators.
CAUTION: Plastic tanks, while stronger than brass, are subject to damage by impact, such as wrenches.
If plastic tank has been damaged, plastic tank and/or O-rings are available for service repair. Tank replacement should be done by qualified personal with proper equipment.
RADIATOR COOLANT FLOW CHECK
The following procedure will determine if coolant is flowing through the cooling system.
If engine is cold, idle engine until normal operating temperature is reached. Then feel the upper radiator hose. If hose is hot, the thermostat is open and water is circulating through cooling system.
RADIATOR REMOVAL/INSTALLATION
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS, RADIATOR CAP, OR
LOOSEN THE RADIATOR DRAINCOCK WITH THE
SYSTEM HOT AND PRESSURIZED.
SERIOUS
BURNS FROM THE COOLANT CAN OCCUR.
DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUM-
BER 6094) (FIG. 26). SNAP-ON CLAMP TOOL (NUM-
BER HPC-20) MAY BE USED FOR LARGER
CLAMPS.
ALWAYS WEAR SAFETY GLASSES
WHEN SERVICING CONSTANT TENSION CLAMPS.
Fig. 26 Hose Clamp Tool—Typical
(3) Position drain pan under draincock. Open radiator draincock. Drain radiator.
(4) Remove radiator upper and lower hose clamps and hoses.
(5) Remove alignment dowel E-clip from radiator lower mounting bracket (Fig. 27).
CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with matching number or letter.
XJ MODELS WITH 2.5L ENGINE
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Observe the previous WARNINGS. Remove radiator cap.
Fig. 27 Radiator Remove/Install—XJ Models—2.5L
Engine
(6) Disconnect coolant reserve/overflow tank hose from radiator.
(7) Remove radiator fan shroud mounting bolts
(Fig. 28). Push shroud back against front of engine.
(8) If equipped, disconnect and plug automatic transmission fluid cooler lines.
(9) Remove radiator top mounting bolts (Fig. 28).
(10) Remove the radiator grille mounting screws.
Remove grille (Fig. 29).
(11) Remove the air conditioning condenser-to-radiator mounting bolt. Use an open end wrench to re-
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COOLING SYSTEM 7 - 23
Fig. 28 Shroud Remove/Install—XJ Models With
2.5L Engine
Fig. 29 Grille Remove/Install—Cherokee Models
With 2.5L Engine move bottom bolts (Fig. 30).
(12) Lift radiator straight up and out of vehicle.
Take care not to damage radiator fins.
INSTALLATION
(1) Install radiator behind air conditioning condenser with bottom alignment dowel inserted into radiator lower mounting bracket.
(2) Install E-clip to alignment dowel.
Fig. 30 Condenser Mounting Bolts—XJ Models With
2.5L Engine
(3) Tighten the four condenser-to-radiator mounting bolts to 6.2 N z m (55 in. lbs.) torque.
(4) Install radiator grille.
(5) Tighten radiator top mounting bolts to 6 N z m
(55 in. lbs.) torque.
(6) If equipped, connect automatic transmission fluid cooler lines to radiator.
(7) Install the radiator fan shroud. Connect the coolant reserve/overflow tank hose.
(8) Connect radiator hoses and install hose clamps.
(9) Connect negative battery cable.
(10) Close the draincock.
(11) Fill cooling system with correct coolant.
(12) Install radiator cap.
(13) Check and adjust automatic transmission fluid level (if equipped).
XJ MODELS WITH 4.0L ENGINE
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND PRES-
SURIZED. SERIOUS BURNS FROM THE COOLANT
CAN OCCUR.
DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
7 - 24 COOLING SYSTEM
J
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUM-
BER 6094) (FIG. 26). SNAP-ON CLAMP TOOL (NUM-
BER HPC-20) MAY BE USED FOR LARGER
CLAMPS.
ALWAYS WEAR SAFETY GLASSES
WHEN SERVICING CONSTANT TENSION CLAMPS.
ment tabs at the bottom are clear of slots in bracket at bottom of radiator (Fig. 32). Place shroud over mechanical fan.
CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with matching number or letter.
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Observe the previous WARNINGS.
(3) Remove pressure cap.
(4) For access to radiator draincock, remove radiator grille (Fig. 29).
(5) Attach one end of a 24 inch long X 1/4 inch ID hose to the radiator draincock. Put the other end into a clean container. Open draincock and drain radiator.
(6) If equipped, disconnect electric cooling fan electrical connector (Fig. 31).
Fig. 31 Auxiliary Fan—Remove/Install
(7) Remove electric fan mounting bolts. Lift fan straight up and out of engine compartment.
(8) Remove the mechanical (non-electrical) fan shroud mounting bolts. Lift shroud up until align-
Fig. 32 Auxiliary Fan and Mechanical Fan
Shroud—Remove/Install—Typical
(9) If equipped, disconnect and plug automatic transmission fluid cooler lines. If equipped with remote cooler, remove line to cooler from bracket at bottom of radiator.
(10) Disconnect radiator upper and lower hoses.
(11) Mark the position of the hood latch striker on the radiator crossmember and remove hood latch striker.
(12) Remove radiator upper crossmember bracket.
(13) Remove radiator upper crossmember.
(14) If equipped with air conditioning, separate radiator from condenser by removing condenser-to-radiator mounting brackets (Fig. 33).
(15) Lift radiator straight up and out of engine compartment taking care not to damage fins.
INSTALLATION
The radiator has two alignment dowels. They are located on the bottom tank and fit into rubber grommets in the radiator lower crossmember.
(1) Lower radiator into engine compartment. Position alignment dowels into grommets in radiator lower crossmember (Fig. 34).
(2) If equipped with air conditioning, attach condenser to radiator with mounting brackets (Fig. 33).
(3) Install radiator upper crossmember.
(4) Install radiator upper crossmember bracket.
(5) Install hood latch striker.
(6) Connect radiator upper and lower hoses.
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Fig. 33 Condenser-to-Radiator Mounting
Brackets—XJ with 4.0L Engine
COOLING SYSTEM 7 - 25
(10) Install mechanical cooling fan shroud. Insert alignment tabs at bottom of shroud into slots in bracket at bottom of radiator. Tighten mounting bolts to 4 N z m (36 in. lbs.) torque (Fig. 32).
(11) Close radiator draincock.
(12) Install grille.
(13) Connect negative battery cable.
(14) Fill cooling system with correct coolant. Refer to the Coolant section of this group.
(15) Install pressure cap.
(16) Check and adjust automatic transmission fluid level (if equipped).
YJ MODELS
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND PRES-
SURIZED. SERIOUS BURNS FROM THE COOLANT
CAN OCCUR.
DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUM-
BER 6094) (FIG. 26). SNAP-ON CLAMP TOOL (NUM-
BER HPC-20) MAY BE USED FOR LARGER
CLAMPS.
ALWAYS WEAR SAFETY GLASSES
WHEN SERVICING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with matching number or letter.
Fig. 34 Radiator Installation—XJ Models with 4.0L
Engine
(7) If equipped, connect automatic transmission fluid cooler lines. If equipped with remote cooler, attach cooler line to bracket at bottom of radiator.
(8) Install electric cooling fan (if equipped). Insert alignment tabs at bottom of fan shroud into slots in bracket at bottom of radiator. Tighten mounting bolts to 4 N z m (36 in. lbs.) torque.
(9) Connect electric cooling fan electrical connector.
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Observe the previous WARNINGS. Remove the radiator cap.
(3) Position drain pan under draincock. Open radiator draincock and drain radiator.
(4) Remove radiator upper and lower hose clamps and hoses.
(5) Disconnect coolant reserve/overflow tank hose from radiator.
(6) Remove fan shroud bolts and push shroud back onto fan (Fig. 35).
(7) If equipped, disconnect and plug automatic transmission fluid cooler lines.
(8) Remove radiator attaching bolts.
(9) Lift radiator straight up and out of vehicle taking care not to damage radiator fins.
7 - 26 COOLING SYSTEM
J
CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with matching number or letter.
Fig. 35 Radiator—Remove/Install—YJ Models
INSTALLATION
(1) Install the radiator. Tighten the mounting bolts to 8 N z m (6 ft. lbs.) torque (Fig. 35).
(2) Close radiator draincock.
(3) Install fan shroud. Tighten mounting bolts to
16 N z m (11 ft. lbs.) torque.
(4) If equipped, remove plugs and connect automatic transmission fluid cooler lines.
(5) Connect radiator hoses and install hose clamps.
(6) Connect negative battery cable.
(7) Fill cooling system with correct coolant. Refer to the Coolant section of this group.
(8) Connect reserve/overflow tank hose.
(9) Install radiator cap.
(10) Check and adjust automatic transmission fluid level (if equipped).
COOLING SYSTEM HOSES
Rubber hoses route coolant to and from the radiator, intake manifold and heater core. All XJ models equipped with air conditioning have a coolant control valve. This is located in-line with the heater core inlet and outlet hoses. It controls coolant flow to the heater core when the air conditioning system is in operation.
Radiator lower hoses are spring-reinforced to prevent collapse from water pump suction at moderate and high engine speeds.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUM-
BER 6094) (FIG. 36). SNAP-ON CLAMP TOOL (NUM-
BER HPC-20) MAY BE USED FOR LARGER
CLAMPS.
ALWAYS WEAR SAFETY GLASSES
WHEN SERVICING CONSTANT TENSION CLAMPS.
Fig. 36 Hose Clamp Tool—Typical
Inspect the hoses at regular intervals. Replace hoses that are cracked, feel brittle when squeezed, or swell excessively when the system is pressurized.
For all vehicles: In areas where specific routing clamps are not provided, be sure that hoses are positioned with sufficient clearance. Check clearance from exhaust manifolds and pipe, fan blades, drive belts and sway bars. Improperly positioned hoses can be damaged, resulting in coolant loss and engine overheating.
Ordinary worm gear type hose clamps (when equipped) can be removed with a straight screwdriver or a hex socket. To prevent damage to hoses or clamps, the hose clamps should be tightened to 4 N z m (34 in. lbs.) torque. Do not over tighten hose clamps.
When performing a hose inspection, inspect the radiator lower hose for proper position and condition of the internal spring.
COOLING SYSTEM FANS
All models are equipped with a mechanical temperature controlled fan. The viscous fan drive is a torque-and-temperature-sensitive clutch unit. It automatically increases or decreases fan speed to provide proper engine cooling. XJ models equipped with a
4.0L engine may also have an auxiliary electrical fan. This is with models that have air conditioning and/or heavy duty cooling.
VISCOUS FAN DRIVE OPERATION
The viscous fan drive (Fig. 37) is a silicone-fluidfilled coupling. On some engines it connects the fan assembly to the fan/water pump pulley. The coupling allows the fan to be driven in a normal manner. This is done at low engine speeds while limiting the top
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COOLING SYSTEM 7 - 27
speed of the fan to a predetermined maximum level at higher engine speeds. A bimetallic spring coil is located on the front face. This spring coil reacts to the temperature of the radiator discharge air. It engages the viscous fan drive for higher fan speed if the air temperature from the radiator rises above a certain point. Until additional engine cooling is necessary, the fan will remain at a reduced rpm regardless of engine speed.
Only when sufficient heat is present, will the viscous fan drive engage. This is when the air flowing through the radiator core causes a reaction from the bimetallic coil. It then increases fan speed to provide the necessary additional engine cooling.
Once the engine has cooled, the radiator discharge temperature will drop. The bimetallic coil again reacts and the fan speed is reduced to the previous disengaged speed.
CAUTION: Engines equipped with serpentine drive belts have reverse rotating fans and viscous fan drives. They are marked with the word REVERSE to designate their usage. Installation of the wrong fan or viscous fan drive can result in engine overheating.
Fig. 37 Viscous Fan Drive—Typical
VISCOUS FAN DRIVE TEST
The cooling system must be in good condition. This is checked prior to performing the following test. It also will ensure against excessively high coolant temperature.
CAUTION: Be sure that there is adequate fan blade clearance before drilling.
(1) Drill a 3.18-mm (1/8-in) diameter hole in the top center of the fan shroud.
(2) Obtain a dial thermometer with an 8 inch stem
(or equivalent). It should have a range of -18°-to-
105°C (0°-to-220° F). Insert thermometer through the hole in the shroud. Be sure that there is adequate clearance from the fan blades.
(3) Connect a tachometer and an engine ignition timing light (timing light is to be used as a strobe light).
(4) Block the air flow through the radiator. Secure a sheet of plastic in front of the radiator (or air conditioner condenser). Use tape at the top to secure the plastic and be sure that the air flow is blocked.
(5) Be sure that the air conditioner (if equipped) is turned off.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
(6) Start the engine and operate at 2400 rpm with the timing light (strobe light) aimed at the fan blades. Within ten minutes the air temperature (indicated on the dial thermometer) should be 88° C
(190° F). Satisfactory operation of the fan drive requires that it engage before or at 88° C (190° F). Engagement is distinguishable by a definite increase in flow noise. The timing light also will indicate an increase in the speed of the fan.
(7) When the air temperature reaches 88° C (190°
F), remove the plastic sheet. Satisfactory operation of the viscous fan requires the air temperature to drop
20° F (11° C) or more. A definite decrease of audiblefan-air-flow-noise should be noticed. Replace defective fan assemblies.
VISCOUS FAN DRIVE REPLACEMENT
REMOVAL
Some engines have the mechanical fan/viscous fan drive assembly mounted directly to the water pump hub (Fig. 38). It may also be mounted to a hub/bearing attached to an aluminum bracket on the right front side of engine (Fig. 39).
(1) Loosen but do not remove at this time, the four fan hub mounting nuts (Figs. 38 or 39).
(2) Remove accessory serpentine drive belt. Refer to Belt Service in the Engine Accessory Drive Belt section of this group.
(3) Some models with certain engines may require the removal of the fan shroud to remove the viscous fan drive. The fan shroud and fan blade/viscous fan drive should be removed from the vehicle as one assembly.
7 - 28 COOLING SYSTEM
Fig. 38 Water Pump Mounted Cooling Fan
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INSTALLATION
(1) Assemble fan blade to viscous fan drive.
Tighten mounting bolts to 27 N z m (20 ft. lbs.) torque.
(2) Position mounting flange of fan blade/viscous fan drive assembly onto hub. Install four nuts and tighten to 24 N z m (18 ft. lbs.) torque. Tighten the first two nuts 180 degrees apart. Then tighten last two nuts.
CAUTION: When installing a serpentine accessory drive belt, the belt MUST be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction. Refer to appropriate
Engine Accessory Drive Belt Schematic in this group for correct belt routing.
(3) Install accessory drive belts. Tension belts to specifications. Refer to the Specifications section at the end of this group.
FAN BLADE INSPECTION
The fan blades cannot be repaired. If the fan is damaged, it must be replaced. Inspect the fan blades as follows:
Lay fan blade assembly on a flat surface with leading edge facing down. With tip of blade touching flat surface, replace fan if clearance between opposite blade and surface is greater than 2.0 mm (.090 inch).
Rocking motion of opposite blades should not exceed
2.0 mm (.090 inch). Test all blades in this manner.
WARNING: DO NOT ATTEMPT TO BEND OR
STRAIGHTEN FAN BLADES IF NOT WITHIN SPECI-
FICATIONS.
Inspect fan assembly for cracks, bends, loose rivets or broken welds. Replace fan if any damage is found.
CAUTION: If the fan blade assembly is replaced because of mechanical damage, the water pump and viscous fan drive should also be inspected. These components could have been damaged due to excessive vibration.
Fig. 39 Bracket Mounted Cooling Fan
(4) Remove four fan hub mounting nuts (Figs. 38 or 39) and remove fan/viscous fan drive assembly from vehicle.
After removing fan blade/viscous fan drive assembly, do not place thermal viscous fan drive in horizontal position. If stored horizontally, silicone fluid in viscous fan drive could drain into its bearing assembly and contaminate lubricant.
AUXILIARY ELECTRIC COOLING FAN—XJ
MODELS WITH 4.0L ENGINE
OPERATION
XJ models equipped with a 4.0L engine may also have an auxiliary electrical fan. This is with models that have air conditioning and/or heavy duty cooling.
The fan is controlled by the cooling fan relay, which is located in the Power Distribution Center (PDC).
For location of relay within the PDC (Fig. 40), refer to label on PDC cover.
When coolant temperature is above 88°C (190°F), the powertrain control module (PCM) grounds the relay. Battery voltage is then applied to the fan
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COOLING SYSTEM 7 - 29
Fig. 40 PDC—XJ Models through the relay. When coolant temperature is below 88°C (190°F), the PCM opens the ground path to the relay. This will prevent the cooling fan from being energized.
Whenever the air conditioning is used, the PCM engages the auxiliary cooling fan. It provides a ground path to the cooling fan relay.
DIAGNOSIS
The powertrain control module (PCM) will enter a diagnostic trouble code (DTC) number 35 in memory if it detects a problem in the auxiliary cooling fan relay or circuit. This will be read as a flashing signal at the instrument panel mounted Malfunction Indicator Lamp (formerly referred to as the Check Engine
Lamp). Refer to On-Board Diagnostics in Group 14,
Fuel Systems for information on accessing a DTC.
The DTC can also be accessed through the DRB scan tool. Refer to the appropriate Powertrain Diagnostic Procedures manual for diagnostic information and operation of the DRB scan tool.
REMOVAL
The auxiliary fan is attached to the radiator upper crossmember behind the radiator.
(1) Remove the fan retaining bolts from radiator upper crossmember (Fig. 41).
(2) Disconnect the electric fan connector.
(3) Lift fan straight up and out of vehicle.
INSTALLATION
(1) Align lower retaining tabs of fan shroud with slots in bracket at bottom of radiator. Push fan down into position.
(2) Tighten the mounting bolts to 4 N z m (31 in.
lbs.) torque.
(3) Connect auxiliary cooling fan electrical connector.
Fig. 41 Auxiliary Fan—Remove/Install
TRANSMISSION OIL COOLERS
WATER-TO-OIL COOLER
All models equipped with an automatic transmission are equipped with a transmission oil cooler mounted internally within the radiator tank. This internal cooler is supplied as standard equipment on all models equipped with an automatic transmission.
Transmission oil is cooled when it passes through this separate cooler. In case of a leak in the internal radiator mounted transmission oil cooler, engine coolant may become mixed with transmission fluid or transmission fluid may enter engine cooling system.
Both cooling system and transmission should be drained and inspected if the internal radiator mounted transmission cooler is leaking.
Also refer to the section on Transmission Air-to-Oil
Coolers. This auxiliary air-to-oil cooler is an option on most engine packages.
REPLACING WATER-TO-OIL COOLER IN
RADIATOR SIDE TANK
The internal transmission oil cooler located within the radiator is not serviceable. If it requires service, the radiator must be replaced.
Once the repaired or replacement radiator has been installed, fill the cooling system and inspect for leaks. Refer to the Refilling Cooling System and
Testing Cooling System For Leaks sections in this group. If the transmission operates properly after repairing the leak, drain the transmission and remove the transmission oil pan. Inspect for sludge and/or rust. Inspect for a dirty or plugged inlet filter. If none of these conditions are found, the transmission
7 - 30 COOLING SYSTEM
J and torque convertor may not require reconditioning.
Refer to Group 21 for automatic transmission servicing.
AIR-TO-OIL COOLER
An auxiliary air-to-oil transmission oil cooler is available with most engine packages.
On XJ and YJ models, the cooler is located in front of the radiator or A/C condenser (if equipped) and behind the grill (Figs. 42 or 43). It is mounted to the front frame crossmember.
The auxiliary oil coolers on all models operate in conjunction with the internal radiator mounted main oil cooler. The transmission oil is routed through the main cooler first, then the auxiliary cooler, before returning to the transmission.
REMOVAL/INSTALLATION—XJ MODELS
(1) Remove the grill. Refer to Group 23, Body.
(2) Place a drain pan below the transmission oil cooler.
(3) Remove the two hose clamps at oil cooler inlet and outlet tubes (Fig. 42).
(4) Remove the two oil cooler mounting bolts (Fig.
42).
(5) Remove the oil cooler from vehicle.
(6) Reverse the preceding operation for installation. Tighten the two clamps 2 N z m (15 in. lbs.) torque.
REMOVAL/INSTALLATION—YJ MODELS
(1) Remove fan shroud and radiator. Refer to
Group 7, Cooling for procedures.
(2) Remove the air conditioning filter/drier mounting bolts.
CAUTION: Before proceeding with the next step, be sure to wear safety glasses. The A/C system is under pressure even with the system off.
(3) Remove the A/C condenser mounting bolts (Fig.
44).
Fig. 42 Auxiliary Air-To-Oil Cooler—YJ Models
Fig. 43 Auxiliary Air-To-Oil Cooler—XJ Models
Fig. 44 Condenser Mounting Bolts—YJ Models
(4) Carefully tilt the A/C condenser rearward for access to the auxiliary transmission oil cooler.
(5) Place a drain pan below the oil cooler.
(6) Remove the two hose clamps at oil cooler inlet and outlet tubes (Fig. 43).
(7) Remove the two oil cooler mounting bolts (Fig.
43).
(8) Remove the oil cooler from vehicle.
(9) Reverse the preceding operation for installation.
Tighten the two clamps 2 N z m (15 in. lbs.) torque.
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ENGINE ACCESSORY DRIVE BELTS
COOLING SYSTEM 7 - 31
INDEX
page
Automatic Belt Tensioner—XJ Models
Belt Diagnosis
. . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Belt Schematics
. . . . . . . . . . . . . . . . . . . . . . . . . 34
Belt Service—Except Right Hand Drive
Belt Service—With Right Hand Drive
page
Belt Tension Specifications
. . . . . . . . . . . . . . . . . 34
Belt Tension—Except Right Hand Drive (RHD)
Belt Tension—Right Hand Drive (RHD)
General Information
. . . . . . . . . . . . . . . . . . . . . . . 31
GENERAL INFORMATION
CAUTION: When installing a serpentine accessory drive belt, the belt MUST be routed correctly. If not, the engine may overheat due to water pump rotating in wrong direction. Refer to the appropriate engine Belt Schematic in this group for the correct belt routing. Or, refer to the Belt Routing Label located in the engine compartment.
BELT DIAGNOSIS
When diagnosing serpentine accessory drive belts, small cracks that run across the ribbed surface of the belt from rib to rib (Fig. 1), are considered normal.
These are not a reason to replace the belt. However, cracks running along a rib (not across) are not normal. Any belt with cracks running along a rib must be replaced (Fig. 1). Also replace the belt if it has excessive wear, frayed cords or severe glazing.
Refer to the Serpentine Accessory Drive Belt Diagnosis charts for further belt diagnosis.
Fig. 1 Serpentine Belt Wear Patterns
7 - 32 COOLING SYSTEM
SERPENTINE DRIVE BELT DIAGNOSIS
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COOLING SYSTEM 7 - 33
SERPENTINE DRIVE BELT DIAGNOSIS (CONT.)
BELT TENSION—EXCEPT RIGHT HAND DRIVE (RHD)
Correct drive belt tension is required to ensure optimum performance of the belt driven engine accessories. There are different types of adjustment gauges for checking either a serpentine or a V-type belt. Refer to the instructions supplied with the gauge. Use the correct gauge when checking belt tension. Place gauge in the middle of the section of belt being tested (between two pulleys) to check tension
(Figs. 2, 3, 4 or 5). Do not allow the gauge (or gauge adapter) to contact anything but the belt.
Fig. 2 YJ Models with 4.0L Engine and XJ Models with 2.5L Engine—With A/C
Fig. 3 YJ Models With 2.5L or 4.0L Engine and XJ
Models with 2.5L Engine—Without A/C
7 - 34 COOLING SYSTEM
BELT TENSION—RIGHT HAND DRIVE (RHD)
XJ MODELS WITH 4.0L ENGINE
It is not necessary to adjust belt tension on RHD vehicles if equipped with a 4.0L engine. The engine is equipped with an automatic belt tensioner (Fig. 7).
The tensioner maintains correct belt tension at all times. Due to the use of this belt tensioner, DO
NOT attempt to use a belt tension gauge on this engine.
BELT TENSION SPECIFICATIONS
Refer to the Specifications section at the end of this group.
BELT SCHEMATICS
The belt routing schematics are published from the latest information available at the time of publication. If anything differs between these schemat- ics and the Belt Routing Label, use the
schematics on Belt Routing Label. This label is located in the engine compartment.
Refer to figures 2, 3, 4 or 5 for proper belt routing on vehicles with conventional left hand drive. Refer to figure 6 for proper belt routing on vehicles with right hand drive (RHD). Or, refer to the Belt Routing
Label located in the vehicle engine compartment.
Fig. 5 XJ Models With 4.0L Engine—With
A/C—Except RHD
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Fig. 4 XJ Models with 4.0L Engine—Without
A/C—Except RHD
BELT SERVICE—EXCEPT RIGHT HAND DRIVE
The following procedures are for models equipped with conventional left hand drive. Also refer to Belt
Service—With Right Hand Drive.
REPLACEMENT/ADJUSTMENT
Belt tension is adjusted at the power steering pump
(or idler pulley if not equipped with power steering).
To adjust belt tension or to replace belt:
(1) Loosen two rear power steering pump mounting bolts A (Fig. 8).
Fig. 6 XJ Models With 4.0L Engine—With A/C—With
RHD
(2) Loosen upper pump pivot bolt B and lower lock nut C (Fig. 9).
(3) Loosen pump adjusting bolt D (Fig. 8).
(4) If belt is to be adjusted, refer to Drive Belt Tension specifications at the end of this group for correct tension and proceed to step 7.
If belt is to be replaced, remove belt.
(5) Check condition of all pulleys.
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COOLING SYSTEM 7 - 35
Fig. 7 Automatic Belt Tensioner—4.0L Engine With
RHD
Fig. 8 P.S. Pump Rear Mounting Bolts—Typical
CAUTION: When installing the serpentine accessory drive belt, the belt MUST be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction. Refer to (Figs. 2, 3, 4 or 5) for correct belt routing.
(6) Install new belt. Refer to the end of this group for Drive Belt Tension specifications.
(7) Tighten pump adjusting bolt D (Fig. 8) to attain proper belt tension.
Fig. 9 P.S. Pump Front Mounting
Bolt/Locknut—Typical
(8) Tighten rear pump mounting bolts, pivot bolt and lock nut to 27 N z m (20 ft. lbs.) torque.
(9) After power steering pump has been tightened into position, recheck belt tension. Adjust if necessary.
BELT SERVICE—WITH RIGHT HAND DRIVE
The following procedures are for XJ models equipped with right hand drive (RHD) and a 4.0L engine.
REMOVAL
(1) Attach a socket/wrench to the mounting bolt of the automatic tensioner pulley (Fig. 7).
(2) Rotate the tensioner assembly clockwise (as viewed from front) until tension has been relieved from belt.
(3) Remove belt from idler pulley (Fig. 7) first. Remove belt from vehicle.
(4) Check condition and alignment of all pulleys.
INSTALLATION
(1) Position the drive belt over all pulleys except the idler pulley (Fig. 7).
CAUTION: When installing the serpentine accessory drive belt, the belt must be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction. Refer to (Fig. 6) for correct engine belt routing. The correct belt with the correct length must be used
(2) Attach a socket/wrench to the pulley mounting bolt of the automatic tensioner (Fig. 7).
7 - 36 COOLING SYSTEM
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(3) Rotate the socket/wrench clockwise (Fig. 7).
Place the belt over the idler pulley. Let tensioner rotate back into place. Remove wrench. Be sure belt is properly seated in the grooves of all pulleys.
AUTOMATIC BELT TENSIONER—XJ MODELS
4.0L ENGINE WITH RIGHT HAND DRIVE
The drive belt is equipped with a spring loaded automatic belt tensioner (Fig. 10). This belt tensioner will be used with all belt configurations such as with or without air conditioning.
REMOVAL
(1) Attach a socket/wrench to the mounting bolt of the automatic tensioner pulley (Fig. 10).
(2) Rotate the tensioner assembly clockwise (as viewed from front) until tension has been relieved from belt.
(3) Remove belt from idler pulley (Fig. 10) first.
Remove belt from automatic tensioner.
(4) Remove tensioner mounting bolt (Fig. 10) from tensioner bracket. Remove tensioner from vehicle.
Note alignment pin on the back of tensioner.
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE AUTO-
MATIC TENSIONER. UNIT IS SERVICED AS AN
ASSEMBLY (EXCEPT FOR PULLEY).
(5) Remove tensioner pulley bolt. Remove pulley from tensioner.
INSTALLATION
(1) Install pulley and pulley bolt to tensioner.
Tighten bolt to 90 N z m (65 ft. lbs.) torque.
(2) Install tensioner assembly to mounting bracket.
An alignment pin is located on the back of tensioner.
Align this pin to the slotted hole in the mounting bracket. Install mounting bolt and tighten to 41 N z m
(30 ft. lbs.) torque. If automatic tensioner bracket-to-
Fig. 10 Automatic Belt Tensioner—4.0L Engine With
RHD generator mounting bracket bolts were removed, tighten to 27 N z m (20 ft. lbs.) torque.
(3) Position the drive belt over all pulleys except the idler pulley (Fig. 10).
CAUTION: When installing the serpentine accessory drive belt, the belt must be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction. Refer to (Fig. 6) for correct engine belt routing. The correct belt with the correct length must be used
(4) Attach a socket/wrench to the pulley mounting bolt of the automatic tensioner (Fig. 10).
(5) Rotate the socket/wrench clockwise (Fig. 10).
Place the belt over the idler pulley. Let tensioner rotate back into place. Remove wrench. Be sure belt is properly seated on all pulleys.
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COOLING SYSTEM 7 - 37
ENGINE BLOCK HEATER
GENERAL INFORMATION
DESCRIPTION AND OPERATION
An optional engine block heater is available for all models. The heater is equipped with a power cord.
The cord is attached to an engine compartment component with tie-straps. The heater warms the engine providing easier engine starting and faster warm-up in low temperatures. The heater is mounted in a core hole of the engine cylinder block (in place of a freeze plug) with the heating element immersed in engine coolant. Connect the power cord to a grounded 110-
120 volt AC electrical outlet with a grounded, threewire extension cord.
WARNING: DO NOT OPERATE ENGINE UNLESS
BLOCK HEATER CORD HAS BEEN DISCONNECTED
FROM POWER SOURCE AND SECURED IN PLACE.
BLOCK HEATER SPECIFICATIONS
• 2.5L Engine: 115 Volts 400 Watts
• 4.0L Engine: 120 Volts 600 Watts
REMOVAL
Refer to correct illustration (Figures 11, 12 or 13) when servicing block heater.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND PRES-
SURIZED. SERIOUS BURNS FROM THE COOLANT
CAN OCCUR.
DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
(1) Drain coolant from radiator and engine cylinder block.
(2) Unplug power cord from block heater.
(3) Loosen screw in center of block heater (Figs.
11, 12 or 13).
(4) Remove block heater from cylinder block.
INSTALLATION
(1) Thoroughly clean the engine core hole and the block heater seat.
(2) Insert block heater assembly into core hole with element loop pointing Up.
(3) Seat block heater flush against block face.
Tighten mounting screw to 3.6 N z m (32 in. lbs.) torque.
(4) Fill cooling system with coolant. Pressurize system and inspect for leaks.
(5) Plug power cord into block heater. Route cord away from moving parts, linkages and exhaust system components. Secure cord in place with tie-straps.
Fig. 11 Heater and Cord—XJ with 2.5L Engine
Fig. 12 Heater and Cord—XJ with 4.0L Engine
Fig. 13 Heater and Cord—YJ Models
7 - 38 COOLING SYSTEM
SPECIFICATIONS
GENERAL INFORMATION
The following specifications are published from the latest information available at the time of publication. If anything differs between the specifica- tions found on the Vehicle Emission Control
Information (VECI) label and the following specifications, use specifications on VECI label.
The VECI label is located in the engine compartment.
BELT TENSION—EXCEPT RHD MODELS
DRIVE BELT TENSION
Belt tension can be adjusted only on models equipped with conventional left hand drive. Refer to the following Belt Tension—Except RHD Models chart for specifications.
It is not necessary to adjust belt tension on right hand drive (RHD) vehicles if equipped with a 4.0L
engine. The engine is equipped with an automatic belt tensioner. The tensioner maintains correct belt tension at all times. Due to the use of this belt tensioner, DO NOT attempt to use a belt ten-
sion gauge on this engine. Refer to Automatic Belt
Tensioner for additional information.
COOLING SYSTEM CAPACITIES
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TORQUE
COOLING SYSTEM 7 - 39
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ELECTRICAL 8A - 1
ELECTRICAL
GROUP INDEX
Group
AUDIO SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . 8F
BATTERY/STARTER/GENERATOR SERVICE . . 8B
BATTERY/STARTING/CHARGING SYSTEMS
DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . . . 8A
CHIME/WARNING BUZZER SYSTEM . . . . . . . 8U
HORNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8G
IGNITION SYSTEMS . . . . . . . . . . . . . . . . . . . . 8D
INSTRUMENT PANEL AND GAUGES . . . . . . . . 8E
LAMPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8L
OVERHEAD CONSOLE . . . . . . . . . . . . . . . . . . . 8C
Group
POWER LOCKS . . . . . . . . . . . . . . . . . . . . . . . . 8P
POWER MIRRORS . . . . . . . . . . . . . . . . . . . . . . 8T
POWER SEAT . . . . . . . . . . . . . . . . . . . . . . . . . . 8R
POWER WINDOWS . . . . . . . . . . . . . . . . . . . . . 8S
REAR WINDOW DEFOGGER . . . . . . . . . . . . . . 8N
TURN SIGNALS AND HAZARD WARNING
FLASHERS . . . . . . . . . . . . . . . . . . . . . . . . . . . 8J
VEHICLE SPEED CONTROL SYSTEM . . . . . . . 8H
WINDSHIELD WIPERS AND WASHERS . . . . . 8K
WIRING DIAGRAMS . . . . . . . . . . . . . . . . . . . . 8W
BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
CONTENTS page
BATTERY TEST PROCEDURES
. . . . . . . . . . . . . 2
ENGINE STARTER MOTOR TEST
PROCEDURES ON VEHICLE
. . . . . . . . . . . . . . 9
page
GENERATOR TEST PROCEDURES ON
VEHICLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
IGNITION OFF DRAW (IOD) DIAGNOSIS . . . . . . 8
USING ON-BOARD DIAGNOSTIC SYSTEM . . . . 19
GENERAL INFORMATION
The battery, starting, and charging systems operate with one another, and therefore, must be thoroughly tested as a complete system. In order for the vehicle to start and charge properly, it must have a battery that will perform to specifications. The starter motor, generator, wiring, and electronics also must perform within specifications. Group 8A covers starting (Fig. 1) and charging (Fig. 2) system diagnostic procedures. These procedures include the most basic conventional methods to On-Board Diagnostics
(OBD) built into the Powertrain Control Module
(PCM). Use of an ammeter, volt/ohmmeter, battery charger, carbon pile rheostat (load tester), and 12volt test lamp will be required.
All OBD sensing systems are monitored by the
PCM. The PCM will store in memory any detectable failure in the monitored circuits. Refer to Using On-
Board Diagnostic System in this group for more information.
Fig. 1 Starting System Components (Typical)
8A - 2 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
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Fig. 2 Charging System Components
BATTERY TEST PROCEDURES
INDEX
page
Battery Charging
. . . . . . . . . . . . . . . . . . . . . . . . . . 5
Battery Diagnostics Chart
. . . . . . . . . . . . . . . . . . . 7
Battery Load Test
. . . . . . . . . . . . . . . . . . . . . . . . . 4
Battery Open Circuit Voltage Test
page
Battery Testing General Information
General Information
. . . . . . . . . . . . . . . . . . . . . . . . 2
Hydrometer Test
. . . . . . . . . . . . . . . . . . . . . . . . . . 3
Specifications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
GENERAL INFORMATION
The battery stores, stabilizes, and produces electrical current. A battery must be able to accept a charge and produce high-amperage current output over an extended period. A chemical reaction occurs between the sulfuric acid solution (electrolyte) and the lead +/− plates in each cell of the battery. As the battery discharges, the plates collect the acid from the electrolyte. When the charging system charges the battery, water is converted to sulfuric acid in the battery. The amount of acid (specific gravity) in the electrolyte can be measured with a hydrometer. The battery is vented to release gases that are created when the battery is being charged.
The battery top, posts, and terminals should be cleaned when other underhood maintenance is performed.
WARNING: DO NOT ATTEMPT TO ASSIST BOOST,
CHARGE, OR TEST BATTERY WHEN ELECTRO-
LYTE LEVEL IS BELOW THE TOP OF THE PLATES.
PERSONAL INJURY MAY OCCUR.
When the electrolyte level is below the top of the plates distilled water should be added. The battery must be completely charged. The top, posts, and terminals should be properly cleaned before diagnostic procedures are performed. See Group 8B - Battery/
Starter/Generator Service, for additional information.
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BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 3
BATTERY TESTING GENERAL INFORMATION
Before testing a battery, clean the top of the battery case, posts and cable terminals.
Specific gravity is a ratio of the density of the electrolyte and the density of pure water. The electrolyte is composed of sulfuric acid and water. Acid makes up approximately 35% of the electrolyte by weight, or 24% by volume.
The condition of a battery may be determined from the results of 2 tests:
• hydrometer test
• ability to supply current (battery load test)
Perform the hydrometer test first. If the specific gravity is less than 1.235, (with battery at room temperature) the battery must be charged before proceeding with further testing. A battery that will not accept a charge is defective and further testing is not necessary.
Completely discharged batteries may take several hours to accept a charge. See Charging
Completely Discharged Battery.
A battery that has been fully charged but does not pass the battery load test is defective.
A battery is fully charged when:
• all cells are gassing freely during charging
• 3 corrected specific gravity tests, taken at 1-hour intervals, indicate no increase in specific gravity.
ABNORMAL BATTERY DISCHARGING
(1) Corroded battery posts and terminals.
(2) Loose or worn generator drive belt.
(3) Electrical loads that exceed the output of the charging system due to equipment or accessories installed after delivery.
(4) Slow driving speeds (heavy traffic conditions) or prolonged idling with high-amperage draw systems in use.
(5) Defective circuit or component causing excess
IOD. Refer to Ignition Off Draw Diagnosis in this group.
(6) Defective charging system.
(7) Defective battery.
HYDROMETER TEST
Before performing a hydrometer test, remove battery caps and check electrolyte level. Add distilled water as required.
Before testing, visually inspect battery for any damage (cracked case or cover, loose post, etc.) that would cause the battery to be defective. To use the hydrometer correctly, hold it with the top surface of the electrolyte at eye level. Refer to manufacturers instructions for correct use of hydrometer.
Remove only enough electrolyte from the battery to keep the float off the bottom of the hydrometer barrel with pressure on the bulb released. Exercise care when inserting the tip of the hydrometer into a cell to avoid damage to the separators. Damaged separators can cause premature battery failure.
Hydrometer floats are generally calibrated to indicate the specific gravity correctly only at one fixed temperature, 80°F (26.6°C). When testing the specific gravity at any other temperature, a correction factor is required.
The correction factor is approximately a specific gravity value of 0.004, referred to as 4 points of specific gravity. For each 10°F above 80°F (5.5°C above
26.6°C), add 4 points. For each 10°F below 80°F
(5.5°C below 26.6°C), subtract 4 points. Always correct the specific gravity for temperature variation.
Test the specific gravity of the electrolyte in each battery cell.
Example: A battery is tested at 10°F (-12.2°C) and has a specific gravity of 1.240. Determine the actual specific gravity as follows:
• Determine the number of degrees above or below
80°F:
80°F - 10°F = 70°F
• Divide the result above by 10:
70°F/10 = 7
•
Multiply the result from the previous step by the temperature correction factor (0.004):
7 x 0.004 = 0.028
• The temperature at testing was below 80°F, therefore the temperature correction is subtracted:
1.240 - 0.028 = 1.212
• The corrected specific gravity is 1.212.
The fully charged battery should have a temperature corrected specific gravity of 1.260 to 1.290.
If the specific gravity of all cells is above 1.235, and cell variation is more than 50 points (0.050), it is an indication that the battery is unserviceable.
If the specific gravity of one or more cells is less than 1.235, charge the battery at a rate of approximately 5 amperes. Continue charging until 3 consecutive specific gravity tests, taken at 1 hour intervals, are constant.
If the cell specific gravity variation is more than 50 points (0.050) after the charge period, replace the battery.
When the specific gravity of all cells is above 1.235
and variation between cells is less than 50 points
(0.050), the battery may be tested under heavy load.
BATTERY OPEN CIRCUIT VOLTAGE TEST
A battery voltage (no load) test will show state of charge of a battery that will pass the Battery Load
Test described in this section. Before proceeding with this test or Battery Load Test, completely charge battery as described in Battery Charging in this section.
If a battery has a no load voltage reading of 12.4
volts or greater and will not endure a load test, it is defective and should be replaced. Refer to Group 8B -
8A - 4 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
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Battery/Starter/Generator Service for instructions. To test battery no load voltage, perform the following operation:
(1) Before measuring open circuit voltage, the surface charge must be removed from plates. Turn headlamps on for 15 seconds then allow up to 5 minutes for voltage to stabilize.
(2) Remove both battery cables, negative first.
(3) Using a voltmeter connected to the battery posts (see instructions provided with voltmeter) measure open circuit voltage (Fig. 3).
This voltage reading will indicate state of charge, but will not reveal cranking capacity. Refer to Battery Open Circuit Voltage chart.
BATTERY OPEN CIRCUIT VOLTAGE
(2) Connect a suitable volt-ammeter-load tester
(Fig. 4) to the battery posts (Fig. 5). Refer to operating instructions provided with the tester being used.
Check the open circuit voltage (no load) of the battery. Voltage should be equal to or greater than 12.4
volts (Fig. 5).
Fig. 4 Volt-Amps-Load Tester (Typical)
Fig. 3 Testing Open Circuit Voltage
BATTERY LOAD TEST
WARNING: IF BATTERY SHOWS SIGNS OF FREEZ-
ING, LEAKING, LOOSE POSTS, OR LOW ELECTRO-
LYTE LEVEL, DO NOT TEST. ACID BURNS OR
EXPLOSIVE CONDITION MAY RESULT.
A battery load test will verify the cranking ability based on the cold crank amperage rating of the battery.
Before performing battery load test, the battery must be FULLY CHARGED.
(1) Remove both battery cables, negative first. Battery top and posts should be clean.
Fig. 5 Volt-Ammeter-Load Tester Connections
(3) Rotate the load control knob (carbon pile rheostat) to apply a 300 amp load for 15 seconds then return the control knob to OFF (Fig. 6). This will remove the surface charge from the battery.
(4) Allow the battery to stabilize to open circuit voltage (may take up to 5 minutes).
(5) Rotate the load control knob to maintain a load
(50% of cold crank amperage rating—see Specifications) for a minimum of 15 seconds (Fig. 7). After 15 seconds, record the (loaded) voltage reading and return the load control knob to OFF.
(6) Voltage drop will vary according to battery temperature at the time of the load test. Battery temperature can be estimated by the ambient temperature over the past several hours. If the battery has been charged, boosted, or loaded a few minutes prior to test, the battery would be somewhat warmer.
Refer to Load Test Temperature chart for proper loaded voltage reading.
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BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 5
dicates battery is charged enough for further testing and possible return to use.
WARNING: DO NOT CHARGE A BATTERY THAT
HAS LOW ELECTROLYTE LEVEL. BATTERY MAY
ARC INTERNALLY AND EXPLODE.
Fig. 6 Remove Surface Charge from Battery
WARNING: EXPLOSIVE GASES FORM OVER BAT-
TERY, DO NOT SMOKE, USE FLAME, OR CREATE
SPARKS NEAR BATTERY.
WARNING: DO NOT ASSIST BOOST OR CHARGE A
FROZEN BATTERY, CASING MAY FRACTURE.
WARNING: POISON, CAUSES SEVERE BURNS.
BATTERY CONTAINS SULFURIC ACID, AVOID CON-
TACT WITH SKIN, EYES, OR CLOTHING. IN EVENT
OF CONTACT, FLUSH WITH WATER AND CALL
PHYSICIAN IMMEDIATELY. KEEP OUT OF REACH
OF CHILDREN.
Fig. 7 Load 50% Cold Crank Rating Note Voltage
(7) If the voltmeter reading fell below 9.6 volts, with the battery temperature at a minimum of 70°F
(21°C), replace the battery.
CAUTION: Always disconnect the battery negative cable before charging battery to avoid damage to electrical systems. Do not exceed 16.0 volts while charging battery.
Battery electrolyte will bubble inside case while being charged properly. If the electrolyte boils or is discharged from the vent holes while charging, immediately reduce charging rate or turn OFF charger and evaluate battery condition.
Battery should not be hot to touch.
If the battery feels hot to the touch, turn OFF charger and let cool before restarting.
Some battery chargers are equipped with polarity
(+ to +/- to -) sensing devices to protect the charger or battery from being damaged if improperly connected. If the battery state of charge is too low for the polarity sensor to detect, the sensor must be bypassed for charger to operate. Refer to operating instructions provided with battery charger being used.
BATTERY CHARGING TIME TABLE
BATTERY CHARGING
A battery is completely charged when it has:
• an open circuit voltage of 12.4 volts or more.
• has enough cranking capacity (minimum 9.6 volts when loaded for 15 seconds to 50% of cold crank amperage rating at 21°C (70°F).
An open circuit voltage of 12.4 volts or greater, in-
8A - 6 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
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After the battery has been charged to 12.4 volts or greater, perform a load test to determine cranking capacity. If the battery will endure a load test, return the battery to use. If battery will not endure a load test, it must be replaced. Clean and inspect battery holddowns, tray, terminals, posts, and top before completing service, see Group 8B - Battery/Starter/
Generator Service.
CHARGING TIME REQUIRED
The time required to charge a battery will vary depending upon the following factors:
(1) Size of Battery— A completely discharged large, heavy-duty battery requires more than twice the recharging time as a completely discharged small capacity battery.
WARNING: NEVER EXCEED 20 AMPS WHEN
CHARGING A COLD (-1°C/30°F) BATTERY, PER-
SONAL INJURY MAY RESULT.
(2) Temperature— A longer time will be needed to charge a battery at -18°C (0°F) than at 27°C
(80°F). When a fast charger is connected to a cold battery, current accepted by battery will be very low at first. Then, in time, the battery will accept a higher rate as battery warms.
(3) Charger Capacity— A charger, that supplies only 5 amperes, will require a longer charging time than a charger that supplies 20 amperes or more.
(4) State Of Charge— A completely discharged battery requires more charging time than a partially charged battery. Electrolyte is nearly pure water in a completely discharged battery. At first the charging current amperage will be low. As the battery charges the specific gravity of the electrolyte will rise slowly.
CHARGING COMPLETELY DISCHARGED
BATTERY
The following procedure should be used to recharge a completely discharged battery. Unless procedure is properly followed, a good battery may be needlessly replaced.
(1) Measure voltage at battery posts with a voltmeter, accurate to 1/10 volt (Fig. 8). If below 10 volts, then charge current will be low and it could take some time before it accepts a current greater than a few milliamperes. Such low current may not be detectable on ammeters built into many chargers.
(2) Connect charger leads. Some chargers feature polarity protection circuitry that prevents operation unless charger is connected to battery posts correctly.
A completely discharged battery may not have enough voltage to activate this circuitry, even though leads are connected properly. This makes it
Fig. 8 Voltmeter Accurate to 1/10 Volt Connected appear that battery will not accept charging current.
Refer to instructions provided with battery charger being used.
(3) Battery chargers vary in the amount of voltage and current they provide. For time required for battery to accept measurable charger current at various voltages, refer to Charge Rate chart. If charge current is still not measurable at end of charging times, the battery should be replaced. If charge current is measurable during charging time, the battery may be good and charging should be completed in the normal manner.
CHARGE RATE
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BATTERY DIAGNOSTICS CHART
BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 7
8A - 8 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
SPECIFICATIONS
BATTERY CLASSIFICATIONS AND RATINGS
TORQUE SPECIFICATIONS
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GENERAL INFORMATION
Ignition off draw refers to power being drained from the battery with the ignition switch turned off.
A normal vehicle electrical system will draw from 5 to 20 milliamps. This is with the ignition switch in the OFF position, and all non-ignition controlled circuits in proper working order. A vehicle that has not been operated for approximately 20 days, may discharge the battery to an inadequate level. Battery drain should not exceed approximately 20 MA (20 milliamps = 0.020 amps).
The 20 MA are needed to supply PCM memory, digital clock memory, and ETR (electronically tuned radio) memory.
Excessive battery drain is caused by items left turned on, internally shorted generator, or intermittent short in wiring.
If the IOD is over 20 milliamperes, the defect must be found and corrected before replacing a battery. In most cases the battery can be charged and returned to service.
When a vehicle will not be used for 20 days or more (stored), remove IOD fuse in the Power Distribution Center to reduce battery discharging.
TEST PROCEDURE
IGNITION OFF DRAW (IOD) DIAGNOSIS
Testing for higher amperage IOD must be performed first to prevent damage to most milliamp meters.
(1) Verify that all electrical accessories are OFF.
Turn off all lamps, remove ignition key, and close all doors. If the vehicle is equipped with electronic accessories (illuminated entry, high line radio), allow the systems to automatically shut off (time out), up to 3 minutes.
(2) Determine that the underhood lamp is operating properly, then disconnect or remove bulb.
(3) Disconnect negative cable from battery.
(4) Connect a typical 12-volt test lamp (low wattage bulb) between the negative cable clamp and the battery negative terminal. If equipped with security alarm, cycle the key in the door to turn off the flashing lights. Make sure that the doors remain closed so that illuminated entry is not activated.
The test lamp may light brightly for up to 3 minutes or may not light at all (depending on the electrical equipment). The term brightly being used throughout the following tests, implies the brightness of the test lamp will be the same as if it were connected across the battery.
The test lamp must be securely clamped to the negative cable and battery terminal. If the test lamp becomes disconnected during any part of the IOD test, the electronic timer function will be activated and all tests must be repeated.
If the ammeter circuit is broken the Security
Alarm Module will turn on parking lamps.
(5) After 3 minutes, the test lamp should turn OFF or be DIMLY lit (depending on the electrical equipment). If the test lamp remains brightly lit do not disconnect it. Remove each fuse or circuit breaker
(refer to Group 8 - Wiring Diagrams) until test lamp is either OFF or DIMLY lit. This will eliminate the higher amperage draw.
If test lamp is still bright after disconnecting each fuse and circuit breaker, disconnect the wiring harness from the generator. Refer to Generator Test Procedures in this group. Do not disconnect the test lamp.
After higher amperage IOD has been corrected, low amperage IOD may be checked.
It is now safe to install milliamp meter to check for low amperage IOD.
(6) With test lamp still connected securely, clamp an ammeter between battery negative terminal and negative battery cable.
Do not open any doors or turn on any electrical accessories with the test lamp disconnected or the meter may be damaged.
(7) Disconnect test lamp. The current draw should not exceed 0.020 amp. If it exceeds 0.020 milliamps, isolate each circuit by removing circuit breakers and fuses. The meter reading drops once the high current problem is found. Repair this section of the circuit, whether it is a wiring short or component failure.
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BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 9
ENGINE STARTER MOTOR TEST PROCEDURES ON VEHICLE
INDEX
page
2.5L Starter Motor Noise Diagnosis
General Information
. . . . . . . . . . . . . . . . . . . . . . . . 9
Starter Control Circuit Tests
. . . . . . . . . . . . . . . . 11
page
Starter Feed Circuit Tests - (Voltage Drop Method)
Starter System Diagnostic Inspections
Starting System Cold Cranking Test
GENERAL INFORMATION
The starting system consists of an:
• ignition switch
• starter relay
• park/neutral position switch (automatic transmission)
• wiring harness
• battery
• starter motor with an integral solenoid.
These components form 2 separate circuits. A high amperage circuit that feeds the starter motor up to
300+ amps, and a control circuit that operates on less than 20 amps.
STARTER SYSTEM DIAGNOSTIC INSPECTIONS
Before removing any unit from the starter motor system for repair, perform the following inspections:
BATTERY INSPECTION
To determine condition of the battery, perform the testing procedure outlined in Battery Test Procedures.
WIRING INSPECTION
Inspect wiring for damage. Inspect all connections at the starter motor solenoid, park/neutral position switch (if equipped), back-up lamp switch connector, ignition switch, starter relay, and battery (including all ground connections). Clean and tighten all connections as required.
SOLENOID, RELAY AND IGNITION SWITCH
INSPECTION
Inspect the solenoid, relay and switch to determine their condition. Also, if equipped with automatic transmission, inspect condition of the park/neutral position switch. Testing information can be found in the following pages.
STARTING SYSTEM COLD CRANKING TEST
(1) Battery must first pass load and voltage drop tests and be fully charged before proceeding. Refer to
Battery Test Procedures.
(2) Connect a suitable volt-ampere tester to the battery terminals (Fig. 1). Refer to the operating instructions provided with the tester being used.
(3) Fully engage parking brake, place manual transmission in NEUTRAL, automatic transmission in PARK.
(4) Verify that all lamps and accessories are OFF.
(5) Remove coil secondary cable from distributor and connect to ground.
(6) Rotate and hold the ignition switch in the
START position. Note cranking voltage and amperage.
(a) If voltage reads above 9.6 volts and amperage draw reads above specifications, go to Starter Feed
Circuit Tests.
(b) If voltage reads 12.5 volts or greater and amperage reads below specifications, go to Starter
Control Circuit Tests.
A cold engine will increase starter motor current and reduce battery voltage.
STARTER FEED CIRCUIT TESTS - (VOLTAGE DROP
METHOD)
The voltage drop tests will determine if there is excessive resistance in the high current circuit. When performing these tests, it is important that the voltmeter be connected to the terminals that the cables are connected to, instead of to the cables themselves.
For example, when testing between the battery and solenoid, touch the voltmeter test probes to the battery post and the solenoid threaded stud. The following operation will require a voltmeter, accurate to
1/10 of a volt.
Before performing the tests, assure the following procedures are accomplished:
• remove coil secondary cable from distributor and connect to ground
• transmission in NEUTRAL (manual transmission) or PARK (automatic transmission)
• parking brake applied
• battery is fully charged (refer to Battery Test Procedures).
8A - 10 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
STARTING SYSTEM DIAGNOSIS
TEST CONDITIONS
• PLACE GEAR SELECTOR IN PARK OR NEUTRAL AND SET PARK BRAKE OR EQUIVALENT.
• VERIFY BATTERY STATE-OF-CHARGE AND CRANKING CAPACITY, SEE BATTERY SECTION.
•
CLEAN BATTERY TOP, POSTS, AND TERMINALS.
•
VERIFY GENERATOR DRIVE BELT TENSION.
• DISCONNECT AND GROUND COIL CABLE.
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Fig. 1 Volt-Amps Tester Connections (Typical)
(1) Connect positive lead of voltmeter to battery negative post. Connect negative voltmeter lead to battery negative cable clamp (Fig. 2). Rotate and hold ignition switch in the START position. Observe voltmeter. If voltage is detected, correct poor contact between cable clamp and post.
(2) Connect positive lead of voltmeter to battery positive post. Connect negative lead to battery cable positive clamp (Fig. 2). Rotate and hold ignition switch in the START position. Observe voltmeter. If voltage is detected, correct poor contact between cable clamp and post.
(3) Connect a voltmeter to measure between the battery positive post and the center of the B+ starter solenoid stud (Fig. 3).
(4) Rotate and hold ignition switch in the START position. If voltage reads above 0.2 volt, correct poor
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BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 11
tact at ground cable attaching point. Voltage reading still above 0.2 volt, replace ground cable.
(7) Connect positive voltmeter lead to starter motor housing. Connect negative lead to battery negative terminal (Fig. 5).
Fig. 2 Test Battery Connection Resistance
Fig. 3 Test Positive Battery Cable Resistance
(Typical) contact at battery cable to solenoid connection. If reading is still above 0.2 volt, replace positive battery cable.
(5) Connect voltmeter to measure between the battery negative post and the engine block (Fig. 4).
Fig. 5 Test Starter Motor Ground (Typical)
(8) Rotate and hold ignition switch in the START position. If voltage reads above 0.2 volt, correct poor starter to engine ground.
If resistance tests detect no feed circuit failures, remove the starter motor and go to Solenoid Testing.
STARTER CONTROL CIRCUIT TESTS
The starter control circuit consists of a starter solenoid, starter relay, ignition switch, park/neutral position switch (automatic transmission), and all their wiring and connections.
Testing procedures for these components are as follows and should be followed in order as described.
CAUTION: Before performing any test, disconnect distributor connector to prevent engine from starting.
SOLENOID TESTING
Refer to Group 8B - Battery/Starter/Generator Service for starter removal procedures.
(1) Disconnect field coil wire from field coil terminal.
(2) Check for continuity between solenoid terminal and field coil terminal with a continuity tester.
There should be continuity (Fig. 6).
Fig. 4 Test Ground Circuit Resistance
(6) Rotate and hold ignition switch in the START position. If voltage reads above 0.2 volt, correct poor con-
Fig. 6 Continuity Test Between Solenoid Terminal and Field Coil Terminal
8A - 12 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
(3) Check for continuity between solenoid terminal and solenoid housing. There should be continuity (Fig. 7).
Fig. 7 Continuity Test Between Solenoid Terminal and Solenoid Case
(4) If there is continuity, solenoid is good. If there is no continuity in either test, solenoid has an open circuit and is defective. Replace starter motor.
(5) Install starter as described in Group 8B.
(6) Connect field coil wire to field coil terminal.
STARTER RELAY OPERATION/TESTING
The starter relay is in the Power Distribution Center (Figs. 8 and 9). Refer to the underside of the
Power Distribution Center cover for relay location.
Fig. 9 Power Distribution Center—YJ
STARTER RELAY CONNECTIONS
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Fig. 8 Power Distribution Center—XJ
OPERATION
• Terminal No. 30 is usually connected to battery voltage and can be switched or B+ at all times.
• Terminal No. 87A is connected to terminal 30 in the de-energized position.
•
Terminal No. 87 is connected to terminal 30 in the energized position which supplies battery voltage to the operated device.
• Terminal No. 86 is connected to the electromagnet and usually connected to a switched power source.
• Terminal No. 85 is connected to the electromagnet and is usually grounded by a switch or Powertrain
Control Module.
TESTING
Remove relay from Power Distribution Center to perform the following tests.
• A relay in the de-energized position should have continuity between terminal 87A and terminal 30.
• Resistance value between terminals 85 and 86
(electromagnet) is 75 6 5 ohms.
• Connect a battery to terminals 85 and 86. There should be continuity between terminal 30 and 87.
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BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 13
IGNITION SWITCH TEST
After testing starter solenoid and relay and they check out OK, trouble is probably with ignition switch or its wiring.
Check all wiring for opens and shorts, and connections for being loose or corroded.
PARK/NEUTRAL POSITION SWITCH
Refer to Group 21 - Transmissions for diagnostic information.
2.5L STARTER MOTOR NOISE DIAGNOSIS
If the complaint is similar to Conditions No. 1 and
No. 2 of chart below, correction can be achieved by proper ‘‘shimming’’ according to the following procedures:
•
Disconnect the battery negative cable (to prevent inadvertent starting of engine).
Two shim thicknesses are available. One is
0.381 mm (0.015 in.) and the other is 1.143 mm
(0.045 in.).
If the complaint is similar to Condition No. 1, the starter motor must be moved toward the flywheel/ driveplate using thinner shims (Fig. 10).
This is generally a condition that causes broken flywheel/driveplate ring gear teeth or broken starter motor housings.
If the complaint is similar to Condition No. 2, the starter motor must be moved away from the flywheel/driveplate. This is done by installing shim(s) across both mounting pads. More than one shim may be required.
8A - 14 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
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Fig. 10 Starter Motor Shimming
GENERATOR TEST PROCEDURES ON VEHICLE
INDEX
page
Diagnostic Procedures
. . . . . . . . . . . . . . . . . . . . . 15
General Information
. . . . . . . . . . . . . . . . . . . . . . . 14
page
Operational Check with Battery Indicator
(Base Cluster Only)
. . . . . . . . . . . . . . . . . . . . . 14
Operational Check with Voltmeter
GENERAL INFORMATION
The generator is belt-driven by the engine. All engines use serpentine drive.
The amount of DC current produced by the generator is controlled by the Powertrain Control Module
(PCM) (Fig. 1).
All vehicles are equipped with On-Board Diagnostics (OBD). All OBD sensing systems are monitored by the PCM. The PCM will store in electronic memory any detectable failure within the monitored circuits. Refer to Using On-Board Diagnostic System in this group for more information.
OPERATIONAL CHECK WITH BATTERY INDICATOR
(BASE CLUSTER ONLY)
When operating normally, the indicator bulb will come on when the ignition switch is turned to the
ON or START position. After the engine starts, the indicator bulb goes off. With the engine running, the charge indicator should come on only when there is a problem in the charging system (base cluster only).
Fig. 1 Charging System Components (Typical)
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BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 15
OPERATIONAL CHECK WITH VOLTMETER
When the ignition switch is turned to the ON position, battery potential will register on the voltmeter. During engine cranking a lower voltage will appear on the meter. With the engine running, a voltage reading higher than the first reading (ignition in ON) should register.
DIAGNOSTIC PROCEDURES
If the indicator operates abnormally, or if an undercharged or overcharged battery condition occurs, the following procedures may be used to diagnose the charging system.
Remember that an undercharged battery is often caused by:
• accessories being left on overnight
• or by a defective switch which allows a bulb, such as a liftgate or glove box light, to stay on (refer to
Ignition Off Draw Diagnosis).
VISUAL INSPECTION
• Inspect condition of battery cable terminals, battery posts, connections at engine block, starter motor solenoid and relay. They should be clean and tight.
Repair as required.
• Inspect all fuses in the fuse block for tightness in receptacles. They should be properly installed and tight. Repair or replace as required.
• Inspect the electrolyte level in the battery and add water if necessary.
• Inspect generator mounting bolts for tightness. Replace or torque bolt as required. Refer to Torque
Specifications in Battery/Starter/Generator Service.
• Inspect generator drive belt condition and tension.
Tension or replace belt as required. Refer to Belt
Tension Specifications in Battery/Starter/Generator
Service.
•
Inspect connection at generator B+ output. It should be clean and tight. Repair as required.
GENERATOR OUTPUT WIRE RESISTANCE
TEST
Generator output wire resistance test will show amount of voltage drop across generator output wire between generator battery terminal and battery positive post.
PREPARATION
(1) Before starting test make sure vehicle has a fully charged battery. Test and procedures on how to check for a fully charged battery are shown in Battery Test Procedures.
(2) Turn OFF ignition switch.
(3) Disconnect negative cable from battery.
(4) Disconnect generator output wire from generator output battery terminal.
Fig. 2 Generator Output Wire Resistance Test (Typical)
8A - 16 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
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(5) Connect a 0-150 ampere scale D.C. ammeter in series between generator battery terminal and disconnected generator output wire (Fig. 2). Connect positive lead to generator battery terminal and negative lead to disconnected generator output wire.
(6) Connect positive lead of a test voltmeter (range
0-18 volts minimum) to disconnected generator output wire. Connect negative lead of test voltmeter to battery positive cable at positive post.
(7) Connect one end of a jumper wire to ground and with other end probe green K20 lead wire at back of generator (Fig. 2). This will generate a DTC.
CAUTION: Do not connect green/orange A142 lead of wiring to ground. Refer to Group 8W - Wiring Diagrams for more information.
(8) Connect an engine tachometer and connect negative cable to battery.
(9) Connect a variable carbon pile rheostat between battery terminals. Be sure carbon pile is in
OPEN or OFF position before connecting leads. See
Load Testing in Battery Test Procedures for instructions.
TEST
(1) Start engine. Immediately after starting, reduce engine speed to idle.
(2) Adjust engine speed and carbon pile to maintain 20 amperes flowing in circuit. Observe voltmeter reading. Voltmeter reading should not exceed 0.5
volts.
RESULTS
If a higher voltage drop is indicated, inspect, clean and tighten all connections between generator battery terminal and battery positive post. A voltage drop test may be performed at each connection to locate connection with excessive resistance. If resistance tested satisfactorily, reduce engine speed, turn
OFF carbon pile and turn OFF ignition switch.
(1) Disconnect negative cable from battery.
(2) Remove test ammeter, voltmeter, carbon pile, and tachometer.
(3) Remove jumper wire.
(4) Connect generator output wire to generator battery terminal. Tighten to 5 to 6 N I m (45 to 75 in.
lbs.).
(5) Connect negative cable to battery.
(6) Use DRB scan tool to erase DTC.
GENERATOR OUTPUT TEST
Generator output test determines whether generator can deliver its rated current output.
PREPARATION
(1) Before starting any tests make sure vehicle has a fully charged battery. Test and procedures on how to check for a fully charged battery are shown in
Battery Test Procedures.
(2) Disconnect negative cable from battery.
(3) Disconnect generator output wire at the generator battery terminal.
(4) Connect a 0-150 ampere scale D.C. ammeter in series between generator battery terminal and disconnected generator output wire (Fig. 3). Connect positive lead to generator battery terminal and negative lead to disconnected generator output wire.
(5) Connect positive lead of a test voltmeter (range
0-18 volts minimum) to generator battery terminal.
(6) Connect negative lead of test voltmeter to a good ground.
(7) Connect an engine tachometer and connect battery negative cable.
(8) Connect a variable carbon pile rheostat between battery terminals. Be sure carbon pile is in
OPEN or OFF position before connecting leads. See
Load Testing in Battery Test Procedures.
(9) Connect one end of a jumper wire to ground and with other end probe green K20 lead wire at back of generator (Fig. 3). This will generate a DTC.
CAUTION: Do not connect green/orange A142 lead of wiring to ground. Refer to Group 8W - Wiring Diagrams for more information.
TEST
(1) Start engine. Immediately after starting reduce engine speed to idle.
(2) Adjust carbon pile and engine speed in increments until a speed of 1250 rpm and voltmeter reading of 15 volts is obtained.
CAUTION: Do not allow voltage meter to read above
16 volts.
(3) The ammeter reading must be within limits shown for that size of generator being tested. See
Generator Specifications in Battery/Starter/Generator Service.
RESULTS
(1) If reading is less than specified and generator output wire resistance is not excessive, generator should be replaced. Refer to Group 8B - Battery/
Starter/Generator Service.
(2) After current output test is completed reduce engine speed, turn OFF carbon pile and turn OFF ignition switch.
(3) Disconnect negative cable from battery.
(4) Remove test ammeter, voltmeter, tachometer and carbon pile.
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BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 17
Fig. 3 Generator Current Output Test (Typical)
(5) Remove jumper wire (Fig. 3).
(6) Connect generator output wire to generator battery terminal. Tighten nut to 5-6 N I m (45-75 in.
lbs.).
(7) Connect negative cable to battery.
(8) Use DRB scan tool to erase DTC.
8A - 18 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS
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BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 19
USING ON-BOARD DIAGNOSTIC SYSTEM
OPERATION OF ON-BOARD DIAGNOSTIC
(OBD) SYSTEM
The Powertrain Control Module (PCM) monitors critical input and output circuits of the charging system making sure they are OK. Some are checked continuously and some are checked only under certain conditions.
If OBD system senses that one critical circuit is bad during the monitoring cycle, it will put a diagnostic trouble code into memory. Each input and output circuit monitored by the OBD system has its own diagnostic trouble code. The diagnostic trouble code
(DTC) will stay in memory as long as the circuit continues to be bad. If the problem does not happen again after the fault code is put into memory, the
PCM is programmed to clear the memory after 50 engine starts.
HOW TO USE MALFUNCTION INDICATOR (CHECK
ENGINE) LAMP FOR DIAGNOSTIC TROUBLE
CODES
To start this function, cycle the ignition switch ON-
OFF-ON-OFF-ON within 5 seconds and any trouble code stored in the PCM will be displayed. The Malfunction Indicator (Check Engine) Lamp will display a DTC by flashing on and off. There is a short pause between flashes and a longer pause between digits.
All codes displayed are two digit numbers with a 4 second pause between codes.
An example of a code is as follows:
(1) Lamp on for 2 seconds, then turns off.
(2) Lamp flashes 4 times pauses and then flashes 1 time.
(3) Lamp pauses for 4 seconds, flashes 4 times, pauses and then flashes 7 times.
The 2 codes are 41 and 47. Any number of codes can be displayed as long as they are in memory. The lamp will flash until all are displayed (55 = End of test).
DIAGNOSTIC TROUBLE CODES (DTC)
Diagnostic trouble codes are two-digit numbers flashed on Malfunction Indicator (Check Engine)
Lamp that identify which circuit is bad. In most cases they do not identify which component in a circuit is bad. A trouble code description can be read using the DRB scan tool. Refer to Group 14 - Fuel
Systems for more information. Therefore, a DTC is only a symptom, not necessarily the cause for the problem. In some cases, because of the design of the driveability test procedure, a DTC can be the reason for the problem. It is important that the test procedure be followed to understand what caused the DTC of the on-board diagnostic system to be set.
CHARGING SYSTEM DIAGNOSTIC TROUBLE
CODES
See Generator Diagnostic Trouble Code chart for diagnostic trouble codes which apply to the charging system. Refer to the Powertrain Diagnostic Procedures manal to diagnose an On-Board Diagnostic
System, Trouble Code.
GENERATOR DIAGNOSTIC TROUBLE CODE (DTC)
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BATTERY/STARTER/GENERATOR SERVICE 8B - 1
BATTERY/STARTER/GENERATOR SERVICE
CONTENTS page
BATTERY SERVICE PROCEDURES
. . . . . . . . . . 1
ENGINE STARTER MOTOR SERVICE
PROCEDURES
. . . . . . . . . . . . . . . . . . . . . . . . . 4
page
GENERATOR SERVICE PROCEDURES
. . . . . . . . 7
SPECIFICATIONS
. . . . . . . . . . . . . . . . . . . . . . . 10
BATTERY SERVICE PROCEDURES
GENERAL INFORMATION
This section covers battery removal and installation procedures only. For diagnostic procedures, refer to Group 8A - Battery/Starting/Charging Systems Diagnostics.
BATTERY MAINTENANCE
(1) Inspect cable terminals for corrosion and damage. Remove the corrosion using a wire brush, or post and terminal cleaner, and a sodium bicarbonate/ water solution. Replace cables that have damaged or deformed terminals.
Be sure filler caps or vents are installed when washing battery to prevent solution from entering battery.
(2) Clean outside of battery case if the original battery is to be installed. Clean top cover with diluted ammonia or a sodium bicarbonate/water solution to remove acid film. Flush with clean water.
Ensure that cleaning solution does not enter cells.
(3) Remove corrosion from the terminals with a wire brush or post and terminal cleaner. Inspect the case for cracks or other damage that would result in leakage of electrolyte.
(4) Check electrolyte level in the battery. Use a putty knife or other suitable wide tool to pry filler caps off low maintenance battery (Fig. 1). Do not use a screwdriver. Add distilled water to each cell until the liquid reaches the bottom of the vent well. DO
NOT OVERFILL.
(5) Operate the engine immediately after adding water (particularly in cold weather) to assure proper mixing of the water and acid.
BATTERY REPLACEMENT—LEFT HAND DRIVE
REMOVAL
(1) Make sure ignition switch is in OFF position and all electrical accessories are OFF.
(2) Loosen the cable terminal clamps.
(3) If necessary, use a puller to remove cable terminal clamps. Remove negative cable terminal clamp first.
Fig. 1 Removing Filler Cap
WARNING: WEAR A SUITABLE PAIR OF RUBBER
GLOVES (NOT THE HOUSEHOLD TYPE) WHEN RE-
MOVING A BATTERY BY HAND. SAFETY GLASSES
ALSO SHOULD BE WORN. IF THE BATTERY IS
CRACKED OR LEAKING, THE ELECTROLYTE CAN
BURN THE SKIN AND EYES.
(4) Remove battery holddown, and remove battery from vehicle (Figs. 2 and 3).
(5) Inspect battery tray and holddowns for corrosion. Remove corrosion using a wire brush and a sodium bicarbonate/water solution. Paint any exposed bare metal. Replace damaged components (Figs. 4 and 5).
INSTALLATION
(1) Refer to Specifications to determine if battery has correct classification and rating for the vehicle.
(2) Use a hydrometer to test the battery electrolyte. Charge battery if necessary.
(3) Position battery in tray. Ensure that positive and negative terminals (posts) are correctly located.
The cables must reach their terminals (posts) without stretching (Figs. 2 and 3).
8B - 2 BATTERY/STARTER/GENERATOR SERVICE
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Fig. 2 Battery Holddown—XJ
Fig. 4 Battery Tray—XJ
Fig. 3 Battery Holddown—YJ
(4) Ensure that tang at battery base is positioned in tray properly before tightening holddown.
CAUTION: It is imperative that the cables are connected to the battery positive-to-positive and negative-to-negative. Reverse polarity will damage the generator diodes and radio(s).
(5) Place felt washer on positive battery terminal.
(6) Connect positive cable first. Then connect negative cable. Tighten both cable terminal bolts to 8.5
N z m (75 in. lbs.).
Fig. 5 Battery Tray—YJ
(7) Apply a thin coating of petroleum jelly or chassis grease to cable terminals and battery posts.
(8) Inspect negative cable connections on engine and vehicle body for condition, security and electrical continuity.
BATTERY REPLACEMENT—RIGHT HAND DRIVE
REMOVAL
(1) Make sure ignition switch is in OFF position and all electrical accessories are OFF.
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BATTERY/STARTER/GENERATOR SERVICE 8B - 3
(2) Remove bolt and negative cable from battery
(Fig. 6).
Fig. 6 Battery Cable Attachment
(3) Remove bolt and positive cable from battery.
WARNING: WEAR A SUITABLE PAIR OF RUBBER
GLOVES (NOT THE HOUSEHOLD TYPE) WHEN RE-
MOVING A BATTERY BY HAND. SAFETY GLASSES
ALSO SHOULD BE WORN. IF THE BATTERY IS
CRACKED OR LEAKING, THE ELECTROLYTE CAN
BURN THE SKIN AND EYES.
(4) Remove battery holddown and battery from vehicle.
(5) Inspect battery tray and holddowns for corrosion. Remove corrosion using a wire brush and a sodium bicarbonate/water solution. Paint any exposed bare metal. Replace damaged components.
INSTALLATION
(1) Refer to Specifications to determine if battery has correct classification and rating for the vehicle.
(2) Use a hydrometer to test the battery electrolyte. Charge battery if necessary.
(3) Position battery in tray. Ensure that positive and negative terminals are correctly located. The cables must reach their terminals without stretching
(Fig. 6).
(4) Ensure that battery base is positioned in tray properly before tightening holddown.
CAUTION: It is imperative that the cables are connected to the battery positive-to-positive and negative-to-negative. Reverse polarity will damage the generator diodes and radio(s).
(5) Connect positive cable first. Then connect negative cable. Tighten both cable terminal bolts to
10-20 N z m (90-178 in. lbs.).
(6) Inspect negative cable connections on engine and vehicle body for condition, security and electrical continuity.
8B - 4 BATTERY/STARTER/GENERATOR SERVICE
ENGINE STARTER MOTOR SERVICE PROCEDURES
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INDEX
page
2.5L Starter General Information
2.5L Starter Motor Removal/Installation
4.0L Starter General Information
4.0L Starter Motor Removal/Installation
page
General Information
. . . . . . . . . . . . . . . . . . . . . . . . 4
Park/Neutral Position Switch
. . . . . . . . . . . . . . . . . 6
Starter Relay Replacement
. . . . . . . . . . . . . . . . . . 4
GENERAL INFORMATION
This section will cover the starting system component service procedures only. For diagnostic procedures, refer to Group 8A - Battery/Starting/Charging
Systems Diagnostics.
Starting system components: battery, starter motor, starter relay, starter solenoid, ignition switch, connecting wires and battery cables. A park/neutral position switch is used with automatic transmissions.
STARTER RELAY REPLACEMENT
The starter relay is located in the Power Distribution Center (Figs. 1 and 2). Refer to underside of
Power Distribution Center cover for relay location.
(1) Disconnect negative cable from battery.
(2) Replace relay.
(3) Connect negative cable to battery.
(4) Test relay operation.
Fig. 2 Power Distribution Center—YJ makes it possible to reduce the dimensions of the starter. This also makes it possible to obtain a higher rotational speed to produce the same torque at the pinion.
The permanent magnet field consists of six twocomponent high strength magnets. The magnets are aligned according to their polarity and are permanently fixed in the starter frame.
The brush holder plate consists of a plastic baseplate with four tubular brush holders.
This unit is highly sensitive to hammering, shocks and external pressure.
CAUTION: The starter motor MUST NOT BE
CLAMPED in a vise by the starter frame. Doing so may damage the magnets. It may be clamped by the mounting flange ONLY.
Fig. 1 Power Distribution Center—XJ
2.5L STARTER GENERAL INFORMATION
The 2.5L engine starter motor incorporates several features to create an efficient, lightweight unit.
A planetary gear system (intermediate transmission) between the electric motor and pinion shaft
CAUTION: Do not connect starter motor incorrectly when tests are being performed. The magnets may be damaged and rendered unserviceable.
•
Ensure cleanliness when performing repairs.
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• Metal chips are attracted by the magnets and may not be completely removed from the starter frame.
Chips in the ring gear can lead to failure of the starter.
2.5L STARTER MOTOR REMOVAL/INSTALLATION
XJ—2.5L ENGINE
(1) Disconnect negative cable from battery.
(2) Remove exhaust clamp from bracket (Fig. 3).
(3) Remove nut and bolt from forward end of brace rod (automatic transmission only).
(4) Remove nut from lower end of brace rod (automatic transmission only).
(5) Remove brace rod and bracket (automatic transmission only).
(6) Remove nut, bolt and bracket from bell housing
(manual transmission only).
BATTERY/STARTER/GENERATOR SERVICE 8B - 5
Fig. 4 Starter Motor Removal/Installation—2.5L XJ
(3) Disconnect solenoid feed wire.
(4) Remove starter motor mounting bolts.
(5) Remove starter motor and shims.
Fig. 3 Exhaust Clamp and Brace Removal—2.5L XJ
(7) Disconnect battery cable and solenoid feed wire from solenoid (Fig. 4).
(8) Remove starter motor mounting bolts, starter motor and shims.
Two shim thicknesses are available. One is
0.381 mm (0.015 in.) and the other is 1.143 mm
(0.045 in.). Refer to Group 8A for proper shim selection.
(9) To install starter motor, reverse the removal procedures and torque mounting hardware as shown.
(10) Connect negative cable to battery.
Fig. 5 Starter Motor Removal/Installation—2.5L YJ
Two shim thicknesses are available. One is
0.381 mm (0.015 in.) and the other is 1.143 mm
(0.045 in.). Refer to Group 8A for proper shim selection.
(6) To install starter motor, reverse removal procedures and torque mounting hardware as shown.
(7) Connect negative cable to battery.
YJ—2.5L ENGINE
(1) Disconnect negative cable from battery.
(2) Disconnect battery cable from starter motor
B+ terminal (Fig. 5).
8B - 6 BATTERY/STARTER/GENERATOR SERVICE
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4.0L STARTER GENERAL INFORMATION
The Mitsubishi starter motor is a light-weight unit featuring a planetary gear drive and permanent magnets for current induction.
The planetary gear drive is splined to both the armature shaft and overrunning clutch. Starter torque is transmitted to the overrunning clutch pinion through the planetary gears which provide higher rotational speeds.
The starter magnetic field is produced by six permanent magnets. The magnets are mounted in the starter frame and positioned according to polarity.
They are permanently attached to the frame and are not removable.
The starter motor is activated by a solenoid mounted on the overrunning clutch housing.
This unit is highly sensitive to hammering, shocks, and external pressure.
CAUTION: The starter motor MUST NOT BE
CLAMPED in a vise by the starter frame. Doing so may damage the magnets. It may be clamped by the mounting flange ONLY.
(3) Disconnect battery wire and solenoid feed wire.
(4) Remove starter lower mounting bolt (Fig. 6).
(5) Remove starter upper mounting bolt and remove starter.
CAUTION: Do not connect the starter motor incorrectly when performing tests. The magnets may be damaged and rendered unserviceable.
• Ensure cleanliness when performing repairs.
• Metal chips are attracted by the magnets and may not be completely removed from the starter frame.
Chips in the ring gear can lead to failure of the starter.
4.0L STARTER MOTOR REMOVAL/INSTALLATION
(1) Disconnect negative cable from battery.
(2) Raise and support vehicle.
Fig. 6 Starter Motor Removal/Installation (Typical)
(6) To install starter motor, reverse the removal procedures and torque mounting hardware as shown.
(7) Remove vehicle support and lower vehicle.
(8) Install negative cable to battery.
PARK/NEUTRAL POSITION SWITCH
Refer to Group 21 for diagnostic, removal and installation procedures.
Check linkage adjustment before replacing the switch.
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BATTERY/STARTER/GENERATOR SERVICE 8B - 7
GENERATOR SERVICE PROCEDURES
GENERAL
The generator is belt-driven by the engine. All engines use serpentine drive. This section will cover generator removal and installation. The generator is not serviceable. Information covering on-vehicle testing can be found in Group 8A - Battery/Starting/
Charging Systems Diagnostics.
GENERATOR REPLACEMENT—LEFT HAND DRIVE
WARNING: FAILURE TO DISCONNECT NEGATIVE
CABLE FROM BATTERY BEFORE DISCONNECTING
RED (OUTPUT) WIRE CONNECTOR FROM GENER-
ATOR CAN RESULT IN INJURY.
ALL YJ AND XJ WITH 2.5L ENGINE
Belt tension is adjusted at the power steering pump
(or idler pulley if not equipped with power steering).
To replace generator:
(1) Disconnect negative cable from battery.
(2) Loosen rear mounting bolts (Fig. 1 or 2).
Fig. 2 Idler Pulley Rear Mounting Bolts—Except XJ
With 4.0L
Fig. 1 Powering Steering Pump Rear Mounting
Bolts—Except XJ With 4.0L
(3) Loosen power steering pump/idler pulley pivot bolt and lock nut (Fig. 3 or 4).
(4) Loosen adjusting bolt to remove belt.
(5) Remove generator B+ terminal nut, 2 field terminal nuts, ground and harness holddown nuts (Fig.
5). Remove wire connector assembly.
(6) Remove 2 generator mounting bolts and remove generator from vehicle.
(7) Install generator with 2 mounting bolts. Torque bolts to 55 N z m (41 ft. lbs.).
(8) Attach generator wires.
CAUTION: Never force a belt over a pulley rim using a screwdriver as the synthetic fiber may be damaged.
Fig. 3 Power Steering Pump Front Mounting
Bolts—Except XJ With 4.0L
CAUTION: When installing a serpentine accessory drive belt, the belt MUST be routed correctly. The engine may overheat because the water pump will be rotating in the wrong direction if the belt is installed incorrectly. Refer to the belt routing label in engine compartment, or see Group 7 - Belt Schematics.
(9) Place serpentine belt over pulley.
(10) Belt tension adjustment is made at power steering pump or idler pulley (Figs. 1 or 2).
(11) Turn adjusting bolt until belt has correct tension. See Belt Tension in Specifications.
8B - 8 BATTERY/STARTER/GENERATOR SERVICE
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Fig. 4 Idler Pulley Front Mounting Bolts—Except XJ
With 4.0L
Fig. 6 Powering Steering Pump Rear Mounting
Bolts—XJ With 4.0L
Fig. 5 Remove or Install Connector Assembly
(12) Tighten rear mounting bolts, pivot bolt, and lock nut to 27 N z m (20 ft. lbs.) torque.
(13) Connect negative cable to battery.
XJ WITH 4.0L ENGINE
Belt tension is adjusted at the power steering pump.
To replace generator:
(1) Disconnect negative cable from battery.
(2) Loosen rear mounting bolts (Fig. 6).
(3) Loosen power steering pump pivot bolt and lock nut (Fig. 7).
(4) Loosen adjusting bolt to remove belt.
(5) Raise and support vehicle.
Fig. 7 Powering Steering Pump Front Mounting
Bolts—XJ With 4.0L
(6) Remove generator B+ terminal nut, 2 field terminal nuts, ground and harness holddown nuts (Fig.
5). Remove wire connector assembly.
(7) Remove 2 generator mounting bolts and remove generator from vehicle.
(8) Install generator with two mounting bolts.
Torque bolts to 55 N z m (41 ft. lbs.).
(9) Attach generator wires.
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CAUTION: Never force a belt over a pulley rim using a screwdriver as the synthetic fiber may be damaged.
BATTERY/STARTER/GENERATOR SERVICE 8B - 9
CAUTION: When installing a serpentine accessory drive belt, the belt MUST be routed correctly. The engine may overheat because the water pump will be rotating in the wrong direction if the belt is installed incorrectly. Refer to the belt routing label in engine compartment, or see Group 7 - Belt Schematics.
(10) Place serpentine belt over pulley.
(11) Belt tension adjustment is made at power steering pump (Fig. 6).
(12) Turn adjusting bolt until belt has correct tension. See Belt Tension in Specifications.
(13) Tighten rear mounting bolts, pivot bolt, and lock nut to 27 N z m (20 ft. lbs.) torque.
(14) Remove support and lower vehicle.
(15) Connect negative cable to battery.
GENERATOR REPLACEMENT—RIGHT HAND DRIVE
The generator used on the right hand drive is the same as used on left hand drive. However, the mounting and accessory drive belt installation are different.
WARNING: FAILURE TO DISCONNECT NEGATIVE
CABLE FROM BATTERY BEFORE DISCONNECTING
RED (OUTPUT) WIRE CONNECTOR FROM GENER-
ATOR CAN RESULT IN INJURY.
(1) Remove negative cable from battery.
(2) Remove 2 screws holding electric cooling fan
(Fig. 8).
(3) Unplug electric cooling fan connector.
(4) Pull fan up and out of vehicle.
(5) Remove generator drive belt. See Group 7 -
Cooling System, for instructions.
(6) Remove generator mounting bolts.
(7) Position generator to gain access to all of the wire connectors.
Fig. 8 Electric Cooling Fan Removal/Installation
(8) Remove B+ terminal nut, 2 field terminal nuts, ground and harness holddown nuts (Fig. 9). Remove wire connector assembly.
Fig. 9 Remove or Install Connector Assembly
(9) Remove generator from vehicle.
(10) To install generator, reverse the removal procedures. Refer to Group 7 for belt installation.
(11) Tighten battery cable bolts to 10-20 N z m (90-
178 in. lbs.).
8B - 10 BATTERY/STARTER/GENERATOR SERVICE
SPECIFICATIONS
BATTERY CLASSIFICATIONS AND
RATINGS—LEFT HAND DRIVE
BATTERY TORQUE SPECIFICATIONS
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BATTERY CLASSIFICATIONS AND
RATINGS—RIGHT HAND DRIVE
BELT TENSION
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4.0L ENGINES
4.0L STARTER MOTOR AND SOLENOID
TESTING SPECIFICATIONS
BATTERY/STARTER/GENERATOR SERVICE 8B - 11
2.5L ENGINES
2.5L STARTER MOTOR SPECIFICATIONS
STARTING SYSTEM COLD CRANKING
SPECIFICATIONS
STARTING SYSTEM COLD CRANKING
SPECIFICATIONS
STARTER MOTOR TORQUE SPECIFICATIONS
STARTER MOTOR TORQUE SPECIFICATIONS
8B - 12 BATTERY/STARTER/GENERATOR SERVICE
GENERATOR SPECIFICATIONS
TORQUE SPECIFICATIONS
OUTPUT VOLTAGE SPECIFICATIONS
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OVERHEAD CONSOLE
OVERHEAD CONSOLE 8C - 1
CONTENTS page
COMPASS REPAIR PROCEDURES
. . . . . . . . . . 4
CONSOLE REPAIR PROCEDURES
. . . . . . . . . . . 6
DESCRIPTION
. . . . . . . . . . . . . . . . . . . . . . . . . . . 1
page
DIAGNOSTIC PROCEDURES
. . . . . . . . . . . . . . . 1
THERMOMETER AND SENSOR SYSTEM REPAIR
PROCEDURES
. . . . . . . . . . . . . . . . . . . . . . . . . 6
DESCRIPTION
The overhead console includes:
• a compass/temperature display
• reading and courtesy lights for the front and rear seats
• the receiver for the keyless entry system
• storage compartment for remote garage door opener
• storage compartment for sunglasses.
COMPASS
The compass will display the direction the vehicle is pointed, using the eight major compass headings
(Examples: North is ‘‘N’’, Northeast is ‘‘NE’’). It does not display the headings in actual degrees. The display is turned on/off using the TEMP/COMP button on the left of the display.
The compass is a self calibrating unit that should not require recalibration. The only calibration that may prove necessary is to drive the vehicle in 3 complete circles, on level ground, in not less than 48 seconds. This will ‘‘reorient’’ the unit to its vehicle. The unit also will compensate for magnetism the vehicle may acquire during its life. Care should be used to avoid putting anything magnetic on the roof of the vehicle.
The unit can compensate for some magnetic fields in the body. The use of magnetic attachments like antenna mounts or repair order ‘‘hats’’ placed directly on the roof can exceed the compensation ability of the unit. Magnetic bit drivers used on the fasteners to hold the assembly to the roof header can also affect operation. If the vehicle roof should become magnetized, then the degaussing and calibration procedures may be required to restore proper operation.
If the compass functions but accuracy is suspect, it may be necessary to perform a variation adjustment.
This procedure allows the unit to accommodate variations in the earth’s magnetic field strength based on geographic location.
If the compass has blanked out and only CAL appears, degaussing may be necessary to remove residual magnetic fields.
THERMOMETER
The ambient temperature display can be changed from Fahrenheit to Celsius using the U.S./METRIC button on the right of the display. The temperature reported is not an instant reading of conditions but an average temperature. It may take the unit several minutes to react to a major change such as driving out of a heated garage into winter temperatures.
When the ignition switch is turned OFF, the last displayed temperature reading stays in memory.
When the ignition switch is turned ON again the thermometer will display the memory temperature for one minute; then update the display to the actual temperature within five minutes.
READING AND COURTESY LAMPS
All reading and courtesy lamps in the overhead console are activated by the door courtesy circuit.
When all four doors and the liftgate are closed the lamps can be activated by depressing the corresponding lens. When any door or the liftgate is open, the switches are disabled. They will not turn the lamps off.
MAP AND COURTESY LAMPS
These lamps offer several unique features. Both the map and courtesy lamps can be turned on with the integral ‘‘Soft Touch’’ switch. Pushing this switch energizes an electrical circuit, which in turn directs power to the light. The map lamps are unaffected by the door switches, while the courtesy lamps are turned on with the opening of any door. When any door is open, the ‘‘Soft Touch’’ switches are disabled, you cannot turn the lights off with these switches.
DIAGNOSTIC PROCEDURES
Follow the appropriate diagnostic flow chart:
• Chart 1 describes the procedures for compass and display problems.
• Chart 2 describes the procedures for illumination lamp problems.
•
Chart 3 describes the procedures for outside temperature measuring problems.
8C - 2 OVERHEAD CONSOLE
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Chart 1
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OVERHEAD CONSOLE 8C - 3
Chart 2
8C - 4 OVERHEAD CONSOLE
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Fig. 1 Variance Settings
COMPASS CALIBRATION PROCEDURE
CAUTION: DO NOT use magnetic tools when servicing the overhead console.
Chart 3
COMPASS REPAIR PROCEDURES
VARIATION ADJUSTMENT PROCEDURE
Variance is the difference between magnetic North and geographic North. In some areas the difference between magnetic and geographic north is great enough to cause the compass to give false readings. If this occurs, the variance must be set.
To set the variance:
(1) Turn ignition switch to the ON position.
(2) Depress both buttons and holddown until VAR light appears. This takes about 5 seconds.
(3) Release both buttons.
(4) Using the map (Fig. 1) find your geographic location and note the zone number.
(5) Press the U.S./METRIC button to sequentially go through the numbers until the zone number for your area appears in the display.
(6) Press the COMP/TEMP button to enter this zone number.
(7) Confirm correct directions are indicated.
CAUTION: DO NOT place any external magnets such as magnetic roof mount antennas, in the vicinity of the compass.
Do not attempt to set compass near large metal objects such as other vehicles, large buildings or bridges. The compass features an ‘‘Auto-Cal’’ design which simplifies the calibration procedure. During normal driving this feature automatically updates the compass calibration. This takes into account incremental changes in magnetism the vehicle may see over its lifetime.
Whenever the compass is calibrated manually, the variation number must also be reset.
Calibrate the compass as follows:
(1) Start the engine.
(2) Depress both buttons on the compass and hold down until CAL light appears. This takes about 10 seconds and appears about 5 seconds after the VAR light appears.
(3) Release buttons.
(4) Drive vehicle on a level surface that is away from metal objects through three or more complete
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OVERHEAD CONSOLE 8C - 5
circles, in not less than 48 seconds. The CAL light will go off and the compass is now calibrated.
(5) Reset variation number. This step must be done every time step 2 is performed.
If CAL light does not go off, either there is excessive magnetism near the compass or the unit is defective. Repeat the degaussing and calibration procedures at least one more time.
If the wrong direction is still indicated, the area selected may be too close to a magnetic source. Repeat the calibration procedure in another location.
DEGAUSSING PROCEDURE
The tool used to degauss or demagnetize the forward console attaching screw and roof panel is the Miller
Tool 6029. Equivalent units must be rated as continuous duty for 110/115 volts, 60Hz with a field strength of over 350 gauss at 1/4 inch beyond the tip of the probe.
In this degaussing procedure the degaussing tool is used to demagnetize both the roof panel and console forward mounting screw.
(1) Be sure the ignition switch is in the OFF position before you begin the degaussing procedures.
CAUTION: Keep the degaussing tool at least 2 inches away from the compass area when plugging it in.
(2) Plug the degaussing tool into a standard
110/115 volt AC outlet.
CONSOLE FORWARD MOUNTING SCREW
(3) Slowly approach the head of the forward mounting screw with the plastic coated tip of the degaussing tool. Contact the head of the screw for about two seconds.
(4) With the degaussing tool still energized, slowly back it away from the screw until the tool is at least
2 inches from the screw head then unplug the tool.
ROOF PANEL
(5) Place an 8 1/2 X 11 piece of paper on the center of the roof at the windshield, oriented lengthwise from front to rear. The purpose of the paper is protect the roof panel from scratches and define the area to be degaussed (Fig. 2). Figure 2 shows the recommended sweep pattern of 1/2 inch between passes in a sweeping zig-zag pattern.
(6) Plug in the degaussing tool. Keep the tool at least 2 inches away from the compass unit.
(7) Slowly approach the center of the roof panel at the windshield with the degaussing tool plugged in.
(8) Contact the roof panel with the tip of the tool
(be sure template is in place to avoid scratching the roof panel). Using slow sweeping motions of 1/2 inch between sweeps, move the tool approximately 4 9 either side of the centerline and at least 11 inches back from the windshield.
Fig. 2 Roof Degaussing Pattern
(9) With the degaussing tool still energized, slowly back it away from the roof panel until the tip is at least 2 inches from the roof then unplug the tool.
(10) Calibrate the compass and set the variance as described.
SELF-DIAGNOSTIC TEST
The self-diagnostic test is used to verify the compass is working properly electrically. This can be used to confirm that the display and all of its segments are operating properly. Initiate the self-diagnostic test as follows:
(1) With the ignition switch in the OFF position simultaneously press and hold the COMP/TEMP button and the US/METRIC button.
(2) Turn ignition switch to ON.
(3) Continue to hold both buttons until the display performs a walking segment test. In this test all of the compass points are displayed along with various number combinations. These combinations verify that all segments work. To repeat the test, press the
COMP/TEMP button.
(4) Press the US/METRIC button, and all segments will light simultaneously for about 2 seconds. To repeat the test, press the COMP/TEMP button.
(5) Press the US/METRIC button to return to normal operation.
8C - 6 OVERHEAD CONSOLE
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(6) Should any segment in any of the digit positions fail to light, the unit is defective and should be replaced.
THERMOMETER AND SENSOR SYSTEM REPAIR
PROCEDURES
This portion of the display consists of a sensor, the circuit and display devoted to the temperature measuring and display. The sensor is mounted at the center of the vehicle below the grille, behind the front bumper (Fig. 3).
CIRCUIT TEST
(1) Locate temperature sensor and disconnect harness connector.
(2) Short the pins on the harness connector by using a jumper wire.
(3) Remove the overhead console as described in
Console Repair Procedures.
(4) Check continuity between pins 10 and 11 of compass/temperature harness connector (Fig. 4). If an open circuit is detected, repair as required.
(5) Remove jumper wire on temperature sensor harness connector. Check continuity between pins 10 and 11 of compass/temperature harness connector
(Fig. 4). If a short is detected, repair as required.
Fig. 4 Compass/Temperature Harness Connector
CONSOLE REPAIR PROCEDURES
(1) Remove screw forward of the compass unit (Fig.
5).
Fig. 3 Temperature Sensor Viewed From
Underneath Vehicle
If an electrical component breaks it will diagnose as an open or short circuit. The system reports SC when the sensor is exposed to temperatures in excess of 140°F or if the circuit is shorted. If the temperature is below
-40°F or an open exists, the system will display OC.
To diagnose the temperature sensor perform the following procedures. If the sensor and wiring are
OK then the electronic module is defective and should be replaced.
SENSOR TEST
(1) Turn the ignition switch to OFF.
(2) Measure resistance of sensor. At -40°F the resistance is 336K ohms. At 140°F the resistance is
2.488K ohms. If resistance is NOT between these two values, then the sensor is faulty. Replace the sensor.
Fig. 5 Remove/Install Overhead Console
(2) Flex housing outward while pressing upward to disengage the housing from the rear bracket (arrow 1)
(Fig. 5).
J
(3) Slide console rearward until the console detaches from the front mounting bracket (arrow 2)
(Fig. 5).
(4) While pressing up on rear of console (arrow 1), slide console forward holding front away from headliner (arrow 2). Move console forward until the rear detaches from headliner and becomes free (Fig. 6).
OVERHEAD CONSOLE 8C - 7
Fig. 8 Keyless Entry Connector
Fig. 6 Remove/Install Overhead Console
(5) Disconnect wire harnesses from keyless entry and compass (Figs. 7 and 8).
Fig. 9 Map Lamp Lens Removal
(3) Replace lens by inserting tab on thin portion of lens into mating slot on console and push upwards on opposite end of lens (Fig. 10).
Fig. 7 Disconnect Wire Harnesses
(6) To install the overhead console, reverse the removal procedures. Be sure to flex housing outward near the keyless entry receiver until the console snaps onto the rear mounting bracket.
BULB REPLACEMENT
(1) With a large paper clip or wire (approximately
0.06 in. diameter) make a hook in the end. Insert into the hole in the lens and pull downward (Fig. 9).
(2) Set lens aside and replace bulb.
Fig. 10 Map Lamp Lens Installation
8C - 8 OVERHEAD CONSOLE
SUNGLASS BIN AND SPRING ASSEMBLY
(1) Open sunglass bin door.
(2) Remove cover plate (Fig. 11).
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Fig. 12 Release Torque Spring
Fig. 11 Remove Cover Plate From Sunglass Bin
(3) Unhook torque spring from wall and put in down position as shown by arrow (Fig. 12).
(4) Remove sunglass bin door by flexing the center panel and removing the side of the door with the gear first (Fig. 13). The gear side of the door has a short pivot rod. Slide door out of the compartment.
(5) Remove and discard push spring (Fig. 11).
(6) Install new push spring as shown. This may require flexing the housing in that area for clearance.
(7) Install new sunglass bin door in the open position as follows:
(a) Make sure the torque spring lines up with the slot in the longer pivot rod then insert the longer pivot rod (Fig. 13).
(b) Flex the center panel and snap in the short pivot rod.
(c) Hook torque spring back over the wall (Fig.
11).
Fig. 13 Remove Sunglass Bin
(d) Cycle door several times to ensure that the door functions properly.
(8) Snap cover plate back in position as shown
(Fig. 11). Some pressure from the inside of the bins may be required to engage all 6 snaps.
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IGNITION SYSTEMS 8D - 1
IGNITION SYSTEMS
CONTENTS page
COMPONENT IDENTIFICATION/SYSTEM
OPERATION
. . . . . . . . . . . . . . . . . . . . . . . . . . 1
COMPONENT REMOVAL/INSTALLATION
. . . . . 20
page
DIAGNOSTICS/SERVICE PROCEDURES
. . . . . . . 8
IGNITION SWITCH
. . . . . . . . . . . . . . . . . . . . . . 30
SPECIFICATIONS
. . . . . . . . . . . . . . . . . . . . . . . 33
COMPONENT IDENTIFICATION/SYSTEM OPERATION
INDEX
page
Automatic Shut Down (ASD) Relay
Camshaft Position Sensor
. . . . . . . . . . . . . . . . . . . 1
Crankshaft Position Sensor
. . . . . . . . . . . . . . . . . . 2
Distributors
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Engine Coolant Temperature Sensor
General Information
. . . . . . . . . . . . . . . . . . . . . . . . 1
page
Ignition Coil
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Intake Manifold Air Temperature Sensor
Manifold Absolute Pressure (MAP) Sensor
Powertrain Control Module (PCM)
Throttle Position Sensor
. . . . . . . . . . . . . . . . . . . . 6
GENERAL INFORMATION
Throughout this group, references are made to particular vehicle models by alphabetical designation
(XJ or YJ) or by the particular vehicle nameplate. A chart showing a breakdown of alphabetical designations is included in the Introduction group at the beginning of this manual.
This section of the group, Component Identification/System Operation, will discuss ignition system operation and will identify ignition system components.
For diagnostic procedures and adjustments, refer to the Diagnostics/Service Procedures section of this group.
For removal and installation of ignition system components, refer to the Component Removal/Installation section of this group.
For other useful information, refer to On-Board Diagnostics in the General Diagnosis sections of Group
14, Fuel System in this manual.
For operation of the DRB Scan Tool, refer to the appropriate Powertrain Diagnostic Procedures service manual.
An Ignition specifications section is included at the end of this group. A general Maintenance Schedule
(mileage intervals) for ignition related items can be found in Group 0, Lubrication and Maintenance. This schedule can also be found in the Owners Manual.
IGNITION SYSTEMS
A multi-port, fuel injected engine is used on all models. The ignition system is controlled by the Powertrain Control Module (PCM) on all engines. The
PCM was formerly referred to as the SBEC or engine controller.
The ignition system consists of:
• Spark Plugs
•
Ignition Coil
•
Secondary Ignition Cables
•
Ignition distributor (contains rotor and camshaft position sensor)
•
Powertrain Control Module (PCM)
• Crankshaft Position Sensor
AUTOMATIC SHUT DOWN (ASD) RELAY
The automatic shut down (ASD) relay is located in the Power Distribution Center (PDC) near the battery (Fig. 1 or 2). As one of its functions, it will supply battery voltage to the ignition coil. The ground circuit for the ASD relay is controlled by the Powertrain Control Module (PCM). The PCM regulates
ASD relay operation by switching the ground circuit on-and-off.
CAMSHAFT POSITION SENSOR
The camshaft position sensor is located in the ignition distributor (Figs. 3 or 4) on all engines.
The camshaft position sensor contains a hall effect device called a sync signal generator to generate a fuel sync signal. This sync signal generator detects a
8D - 2 IGNITION SYSTEMS
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Fig. 1 PDC—XJ Models
Fig. 3 Camshaft Position Sensor—Typical
Fig. 2 PDC—YJ Models rotating pulse ring (shutter) on the distributor shaft
(Fig. 4). The pulse ring rotates 180 degrees through the sync signal generator. Its signal is used in conjunction with the crankshaft position sensor to differentiate between fuel injection and spark events. It is also used to synchronize the fuel injectors with their respective cylinders.
When the leading edge of the pulse ring (shutter) enters the sync signal generator, the following occurs: The interruption of magnetic field causes the voltage to switch high resulting in a sync signal of approximately 5 volts.
When the trailing edge of the pulse ring (shutter) leaves the sync signal generator, the following occurs: The change of the magnetic field causes the sync signal voltage to switch low to 0 volts.
For component testing, refer to the Diagnostics/Service Procedures section of this group.
For removal and installation of this component, refer to the Component Removal/Installation section of this group.
Fig. 4 Distributor—Typical
CRANKSHAFT POSITION SENSOR
The crankshaft position sensor is mounted to the transmission bellhousing at the left/rear side of the engine block (Figs. 5, 6 or 7).
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IGNITION SYSTEMS 8D - 3
Fig. 5 Crankshaft Position Sensor—2.5L
Engine—Typical
Fig. 6 Crankshaft Position Sensor—4.0L Engine—All
Except YJ models With Automatic Transmission
Engine speed and crankshaft position are provided through the crankshaft position sensor. The sensor generates pulses that are the input sent to the Powertrain Control Module (PCM). The PCM interprets the sensor input to determine the crankshaft position. The PCM then uses this position, along with other inputs, to determine injector sequence and ignition timing.
The sensor is a hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it.
SENSOR OPERATION
The flywheel/drive plate has groups of four notches at its outer edge. On 4.0L 6 cylinder engines there are three sets of notches (Figs. 9 or 10). On 2.5L 4 cylinder engines there are two sets of notches (Fig.
8).
The notches cause a pulse to be generated when they pass under the sensor. The pulses are the input
Fig. 7 Crankshaft Position Sensor—4.0L Engine—YJ models With Automatic Transmission to the PCM. For each engine revolution there are two groups of four pulses generated on 2.5L 4 cylinder engines. There are 3 groups of four pulses generated on 4.0L 6 cylinder engines.
The trailing edge of the fourth notch, which causes the pulse, is four degrees before top dead center
(TDC) of the corresponding piston.
The engine will not operate if the PCM does not receive a crankshaft position sensor input.
For component testing, refer to the Diagnostics/Service Procedures section of this group.
For removal and installation of this sensor, refer to the Component Removal/Installation section of this group.
DISTRIBUTORS
All engines are equipped with a camshaft driven mechanical distributor containing a shaft driven distributor rotor. All distributors are equipped with an internal camshaft position (fuel sync) sensor. This sensor provides fuel injection synchronization and cylinder identification.
The distributors on the 2.5L and 4.0L engines do not have built in centrifugal or vacuum assisted advance. Base ignition timing and all timing advance is controlled by the Powertrain Control Module
(PCM). Because ignition timing is controlled by the
PCM, base ignition timing is not adjustable on any of these engines.
The distributor is locked in place by a notch on the distributor housing. The distributor holddown clamp bolt passes through this notch when installed. Because the distributor position is locked when in-
8D - 4 IGNITION SYSTEMS
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Fig. 8 Sensor Operation—2.5L Engine Fig. 10 Sensor Operation—4.0L Engine—YJ Models
With Automatic Transmission
For removal and installation of this component, refer to the Component Removal/Installation section of this group.
Fig. 9 Sensor Operation—4.0L Engine—All Except
YJ Models With Automatic Transmission stalled, its rotational position can not be changed.
Do not attempt to modify the distributor housing to get distributor rotation. Distributor position will have no effect on ignition timing.
All distributors contain an internal oil seal that prevents oil from entering the distributor housing.
The seal is not serviceable.
For component testing, refer to the Diagnostics/Service Procedures section of this group.
IGNITION COIL
Battery voltage is supplied to the ignition coil positive terminal from the ASD relay.
The Powertrain Control Module (PCM) opens and closes the ignition coil ground circuit for ignition coil operation.
Base ignition timing is not adjustable. By controlling the coil ground circuit, the PCM is able to set the base timing and adjust the ignition timing advance. This is done to meet changing engine operating conditions.
The ignition coil is not oil filled. The windings are embedded in an epoxy compound. This provides heat and vibration resistance that allows the ignition coil to be mounted on the engine.
The ignition coil is mounted to a bracket on the side of the engine (Fig. 11).
For component testing, refer to the Diagnostics/Service Procedures section of this group.
For removal and installation of this component, refer to the Component Removal/Installation section of this group.
ENGINE COOLANT TEMPERATURE SENSOR
The engine coolant temperature sensor provides an input voltage to the Powertrain Control Module
(PCM) relating coolant temperature. The PCM uses this input, along with inputs from other sensors, to determine injector pulse width and ignition timing.
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IGNITION SYSTEMS 8D - 5
manifold air temperature. The input from this sensor is used along with inputs from other sensors to determine injector pulse width. As the temperature of the air-fuel stream in the manifold varies, the sensor resistance will change. This will result in a different input voltage to the PCM. For more information, refer to Group 14, Fuel System.
This sensor is installed in the intake manifold (Fig.
13, 4.0L engine or Fig. 14, 2.5L engine).
Fig. 11 Ignition Coil—Typical
As coolant temperature varies, the sensor resistance will change, resulting in a different input voltage to the PCM.
When the engine is cold, the PCM will operate in the Open Loop Cycle. It will demand slightly richer air-fuel mixtures and higher idle speeds, until normal operating temperatures are reached. Refer to
Modes Of Operation in Group 14, Fuel System for a description of Open and Closed Loop operation.
This sensor is installed in the thermostat housing
(Fig. 12).
Fig. 13 Air Temperature Sensor Location—4.0L
Engine
Fig. 12 Coolant Temperature Sensor—Typical
For component testing, refer to the Diagnostics/Service Procedures section of this group.
For removal and installation of this component, refer to the Component Removal/Installation section of this group.
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
The sensor element extends into the intake manifold air stream. It provides an input voltage to the
Powertrain Control Module (PCM) indicating intake
Fig. 14 Air Temperature Sensor Location—2.5L
Engine
For component testing, refer to the Diagnostics/Service Procedures section of this group.
For removal and installation of this component, refer to the Component Removal/Installation section of this group.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
The MAP sensor reacts to absolute pressure in the intake manifold and provides an input voltage to the
Powertrain Control Module (PCM). As engine load changes, manifold pressure varies, causing the MAP
8D - 6 IGNITION SYSTEMS
sensor voltage to change. This change results in a different input voltage to the PCM. The input voltage level supplies the PCM with information. This relates to ambient barometric pressure during engine start-up (cranking) and to engine load while the engine is running. The PCM uses this input, along with inputs from other sensors, to adjust air-fuel mixture.
For more information, refer to Group 14, Fuel System.
The MAP sensor is located in the engine compartment near the rear of engine cylinder head (valve) cover (Fig. 15). It is connected to the throttle body with a vacuum hose and to the PCM electrically.
Fig. 16 PCM Location—XJ Models
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Fig. 15 MAP Sensor—Typical
For component testing, refer to the Diagnostics/Service Procedures section of this group.
For removal and installation of this component, refer to the Component Removal/Installation section of this group.
POWERTRAIN CONTROL MODULE (PCM)
The PCM was formerly referred to as the SBEC or engine controller. On XJ models, the PCM is located in the engine compartment next to the air cleaner
(Fig. 16). On YJ models, the PCM is located in the engine compartment behind the windshield washer fluid reservoir (Fig. 17).
The ignition system is controlled by the PCM.
Base ignition timing by rotation of distributor
is not adjustable. The PCM opens and closes the ignition coil ground circuit to operate the ignition coil.
This is done to adjust ignition timing, both initial
(base) and advance, for changing engine operating conditions.
The amount of electronic spark advance provided by the PCM is determined by five input factors: Engine coolant temperature, engine rpm, intake manifold air temperature, intake manifold absolute pressure and throttle position.
Fig. 17 PCM Location—YJ Models
For removal and installation of this component, refer to the Component Removal/Installation section of this group.
For diagnostics, refer to the appropriate Powertrain
Diagnostic Procedures service manual for operation of the DRB scan tool.
THROTTLE POSITION SENSOR
The sensor is mounted on the throttle body (Figs.
18 or 19). It is connected to the throttle blade shaft.
The sensor is a variable resistor. It provides the Powertrain Control Module (PCM) with an input signal
(voltage) that represents throttle blade position. As the position of the throttle blade changes, the resistance of the sensor changes.
The PCM supplies approximately 5 volts to the sensor. The sensor output voltage (input signal to the
PCM) represents the throttle blade position. The
PCM receives an input signal voltage from the sensor. This will vary in an approximate range of from 1 volt at minimum throttle opening (idle), to 4 volts at wide open throttle. Along with inputs from other sensors, the PCM uses the sensor input to determine
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IGNITION SYSTEMS 8D - 7
Fig. 18 Throttle Position Sensor—2.5L Engine current engine operating conditions. It will also adjust fuel injector pulse width and ignition timing.
Fig. 19 Throttle Position Sensor—4.0L Engine
For component testing, refer to the Diagnostics/Service Procedures section of this group.
For removal and installation of this component, refer to the Component Removal/Installation section of this group.
8D - 8 IGNITION SYSTEMS
DIAGNOSTICS/SERVICE PROCEDURES
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INDEX
page
Automatic Shut Down (ASD) Relay
Camshaft Position Sensor Test
. . . . . . . . . . . . . . . 8
Crankshaft Position Sensor Test
Distributor Cap
. . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Distributor Rotor
. . . . . . . . . . . . . . . . . . . . . . . . . 10
DRB Scan Tool
. . . . . . . . . . . . . . . . . . . . . . . . . . 10
Engine Coolant Temperature Sensor Test
General Information
. . . . . . . . . . . . . . . . . . . . . . . . 8
Ignition Coil
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Ignition Secondary Circuit Diagnosis
page
Ignition Timing
. . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Intake Manifold Air Temperature Sensor Test
Manifold Absolute Pressure (MAP) Sensor Test
On-Board Diagnostics (OBD)
. . . . . . . . . . . . . . . . 19
Oxygen Sensor Tests
. . . . . . . . . . . . . . . . . . . . . 19
Powertrain Control Module (PCM)
Spark Plug Secondary Cables
. . . . . . . . . . . . . . . 17
Spark Plugs
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Throttle Position Sensor Test
. . . . . . . . . . . . . . . 18
GENERAL INFORMATION
This section of the group, Diagnostics/Service Procedures, will discuss basic ignition system diagnostics and service adjustments.
For system operation and component identification, refer to the Component Identification/System Operation section of this group.
For removal or installation of ignition system components, refer to the Component Removal/Installation section of this group.
For other useful information, refer to On-Board Diagnostics in the General Diagnosis sections of Group
14, Fuel System in this manual.
For operation of the DRB Scan Tool, refer to the appropriate Powertrain Diagnostic Procedures service manual.
AUTOMATIC SHUT DOWN (ASD) RELAY
Refer to Relays—Operation/Testing in the Group
14, Fuel System section of this service manual.
CAMSHAFT POSITION SENSOR TEST
The camshaft position sensor is located in the distributor on all engines.
To perform a complete test of this sensor and its circuitry, refer to the DRB scan tool. Also refer to the appropriate Powertrain Diagnostics Procedures manual. To test the sensor only, refer to the following:
(2) Connect the negative (-) voltmeter lead into the ground wire. For wire identification, refer to Group
8W, Wiring Diagrams.
(3) Set the voltmeter to the 15 Volt DC scale.
(4) Remove distributor cap. Rotate (crank) engine with starter until pulse ring (Fig. 1) enters the magnetic pickup on camshaft position sensor. Distributor rotor should be pointed in 9 o’clock position. The movable pulse ring should now be within the sensor pickup.
2.5L OR 4.0L ENGINE
For this test, an analog voltmeter is needed. Do not remove the distributor connector from the distributor. Using small paper clips, insert them into the backside of the distributor wire harness connector to make contact with the terminals. Be sure that the connector is not damaged when inserting the paper clips. Attach voltmeter leads to these paper clips.
(1) Connect the positive (+) voltmeter lead into the sensor output wire. This is at done the distributor wire harness connector. For wire identification, refer to Group 8W, Wiring Diagrams.
Fig. 1 Pulse Ring/Rotor Position—Typical
(5) Turn ignition key to ON position. Voltmeter should read approximately 5.0 volts.
(6) If voltage is not present, check the voltmeter leads for a good connection.
(7) If voltage is still not present, check for voltage at the supply wire. For wire identification, refer to
Group 8W, Wiring Diagrams.
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IGNITION SYSTEMS 8D - 9
(8) If voltage is not present at supply wire, check for voltage at pin 7 of Powertrain Control Module
(PCM) 60-way connector. Leave the PCM connector connected for this test.
(9) If voltage is still not present, perform vehicle test using the DRB scan tool.
(10) If voltage is present at pin 7, but not at the supply wire:
(a) Check continuity between the supply wire.
This is checked between the distributor connector and pin 7 at the PCM. If continuity is not present, repair the harness as necessary.
(b) Check for continuity between the camshaft position sensor output wire and pin 44 at the PCM.
If continuity is not present, repair the harness as necessary.
(c) Check for continuity between the ground circuit wire at the distributor connector and ground.
If continuity is not present, repair the harness as necessary.
(11) While observing the voltmeter, crank the engine with ignition switch. The voltmeter needle should fluctuate between 0 and 5 volts while the engine is cranking. This verifies that the camshaft position sensor in the distributor is operating properly and a sync pulse signal is being generated.
If sync pulse signal is not present, replacement of the camshaft position sensor is necessary.
For removal or installation of ignition system components, refer to the Component Removal/Installation section of this group.
For system operation and component identification, refer to the Component Identification/System Operation section of this group.
CRANKSHAFT POSITION SENSOR TEST
To perform a complete test of this sensor and its circuitry, refer to the DRB scan tool. Also refer to the appropriate Powertrain Diagnostics Procedures manual. To test the sensor only, refer to the following:
The sensor is located on the transmission bellhousing at the left/rear side of the engine block (Figs. 2, 3 or 4).
(1) Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
(2) Place an ohmmeter across terminals B and C
(Fig. 5). Ohmmeter should be set to 1K-to-10K scale for this test. The meter reading should be open (no resistance). Replace sensor if a low resistance is indicated.
For removal or installation of ignition system components, refer to the Component Removal/Installation section of this group.
Fig. 2 Crankshaft Position Sensor—2.5L
Engine—Typical
Fig. 3 Crankshaft Position Sensor—4.0L Engine—All
Except YJ models With Auto. Trans.
DISTRIBUTOR CAP
INSPECTION
Remove the distributor cap and wipe it clean with a dry lint free cloth. Visually inspect the cap for cracks, carbon paths, broken towers, or damaged rotor button (Figs. 6 and 7). Also check for white deposits on the inside (caused by condensation entering the cap through cracks). Replace any cap that displays charred or eroded terminals. The machined surface of a terminal end (faces toward rotor) will indicate some evidence of erosion from normal operation. Examine the terminal ends for evidence of mechanical interference with the rotor tip.
If replacement of the distributor cap is necessary, transfer spark plug cables from the original cap to the new cap. This should be done one cable at a time.
Each cable is installed onto the tower of the new cap that corresponds to its tower position on the original cap. Fully seat the cables onto the towers. If neces-
8D - 10 IGNITION SYSTEMS
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Fig. 4 Crankshaft Position Sensor—4.0L Engine—YJ models With Auto. Trans.
Fig. 6 Cap Inspection—External—Typical
Fig. 7 Cap Inspection—Internal—Typical
Fig. 5 Crankshaft Position Sensor Connector sary, refer to the engine Firing Order diagrams
(Figs. 8 or 9).
DISTRIBUTOR ROTOR
Visually inspect the rotor (Fig. 10) for cracks, evidence of corrosion, or the effects of arcing on the metal tip. Also check for evidence of mechanical interference with the cap. Some charring is normal on the end of the metal tip. The silicone-dielectric-varnish-compound applied to the rotor tip for radio interference noise suppression, will appear charred.
This is normal. Do not remove the charred com-
pound. Test the spring for insufficient tension. Replace a rotor that displays any of these adverse conditions.
Fig. 8 Firing Order—2.5L 4 Cylinder Engine
DRB SCAN TOOL
For operation of the DRB scan tool, refer to the appropriate Powertrain Diagnostic Procedures service manual.
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IGNITION SYSTEMS 8D - 11
IGNITION COIL
To perform a complete test of the ignition coil and its circuitry, refer to the DRB scan tool. Also refer to the appropriate Powertrain Diagnostics Procedures manual. To test the coil only, refer to the following:
The ignition coil (Fig. 11) is designed to operate without an external ballast resistor.
Fig. 9 Firing Order—4.0L 6 Cylinder Engine
Fig. 11 Ignition Coil—Typical
Inspect the ignition coil for arcing. Test the coil according to coil tester manufacturer’s instructions.
Test the coil primary and secondary resistance. Replace any coil that does not meet specifications. Refer to the Ignition Coil Resistance chart.
If the ignition coil is being replaced, the secondary spark plug cable must also be checked. Replace cable if it has been burned or damaged.
Arcing at the tower will carbonize the cable nipple, which if it is connected to a new ignition coil, will cause the coil to fail.
If the secondary coil cable shows any signs of damage, it should be replaced with a new cable and new terminal. Carbon tracking on the old cable can cause arcing and the failure of a new ignition coil.
Fig. 10 Rotor Inspection—Typical
IGNITION COIL RESISTANCE
8D - 12 IGNITION SYSTEMS
ENGINE COOLANT TEMPERATURE SENSOR TEST
To perform a complete test of this sensor and its circuitry, refer to the DRB scan tool. Also refer to the appropriate Powertrain Diagnostics Procedures manual. To test the sensor only, refer to the following:
The sensor is installed in the thermostat housing
(Fig. 12).
(1) Disconnect wire harness connector from sensor
(Fig. 12).
SENSOR RESISTANCE (OHMS)
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Fig. 12 Coolant Temperature Sensor—Typical
(2) Test the resistance of the sensor with a high input impedance (digital) volt-ohmmeter. The resistance should be less than 1340 ohms at normal engine operating idle temperature. For resistance values, refer to the Sensor Resistance chart. Replace the sensor if it is not within the range of resistance specified in the chart.
(3) Test continuity of the wire harness. This is done between Powertrain Control Module (PCM) wire harness connector terminal-2 and the sensor connector terminal. Also check continuity between wire harness terminal-4 to the sensor connector terminal. Repair the wire harness if an open circuit is indicated.
IGNITION SECONDARY CIRCUIT DIAGNOSIS
CHECKING FOR SPARK
CAUTION: When disconnecting a high voltage cable from a spark plug or from the distributor cap, twist the rubber boot slightly (1/2 turn) to break it loose.
Grasp the boot (not the cable) and pull it off with a steady, even force.
(1) Disconnect the ignition coil secondary cable from center tower of the distributor cap. Hold the cable terminal approximately 12 mm (1/2 in.) from a good engine ground (Fig. 13).
Fig. 13 Checking for Spark—Typical
WARNING: BE VERY CAREFUL WHEN THE ENGINE
IS CRANKING. DO NOT PUT YOUR HANDS NEAR
THE PULLEYS, BELTS OR THE FAN. DO NOT
WEAR LOOSE FITTING CLOTHING.
(2) Rotate (crank) the engine with the starter motor and observe the cable terminal for a steady arc. If steady arcing does not occur, inspect the secondary coil cable. Refer to Spark Plug Cables in this group.
Also inspect the distributor cap and rotor for cracks or burn marks. Repair as necessary. If steady arcing occurs, connect ignition coil cable to the distributor cap.
(3) Remove a cable from one spark plug.
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IGNITION SYSTEMS 8D - 13
(4) Using insulated pliers, hold the cable terminal approximately 12 mm (1/2 in.) from the engine cylinder head or block while rotating the engine with the starter motor. Observe the spark plug cable terminal for an arc. If steady arcing occurs, it can be expected that the ignition secondary system is operating correctly. If steady arcing occurs at the spark plug cables, but the engine will not start, connect the DRB scan tool. Refer to the Powertrain Diagnostic Procedures service manual for DRB operation.
FAILURE TO START TEST
To prevent unnecessary diagnostic time and wrong test results, the previous Checking For Spark test should be performed prior to this test.
WARNING: SET PARKING BRAKE OR BLOCK THE
DRIVE WHEELS BEFORE PROCEEDING WITH THIS
TEST.
(1) Unplug the ignition coil harness connector at the coil (Fig. 14).
Fig. 15 Coil Terminals—Typical
60-way connector (Fig. 16) from the PCM. Check 60way connector for any spread terminals.
Fig. 16 PCM 60-Way Connector
(5) Remove test lead from the coil positive terminal. Connect an 18 gauge jumper wire between the battery positive terminal and the coil positive terminal.
(6) Make the special jumper shown in Figure 17.
Using the jumper, momentarily ground terminal-19 of the 60-way connector. A spark should be generated at the coil cable when the ground is removed.
Fig. 14 Coil Harness Connector—Typical
(2) Connect a set of small jumper wires (18 gauge or smaller) between the ignition coil and coil electrical connector (Fig. 15).
(3) Determine that sufficient battery voltage (12.4
volts) is present for the starting and ignition systems.
(4) Crank the engine for 5 seconds while monitoring the voltage at the coil positive terminal:
• If the voltage remains near zero during the entire period of cranking, refer to On-Board Diagnostics in
Group 14, Fuel Systems. Check the powertrain control module (PCM) and auto shut down relay.
• If voltage is at near battery voltage and drops to zero after 1-2 seconds of cranking, check the camshaft position sensor-to-PCM circuit. Refer to On-
Board Diagnostics in Group 14, Fuel Systems.
•
If voltage remains at near battery voltage during the entire 5 seconds, turn the key off. Remove the
Fig. 17 Special Jumper Ground-to-Coil Negative
Terminal
(7) If spark is generated, replace the powertrain control module (PCM).
(8) If spark is not seen, use the special jumper to ground the coil negative terminal directly.
(9) If spark is produced, repair wiring harness for an open condition.
8D - 14 IGNITION SYSTEMS
(10) If spark is not produced, replace the ignition coil.
IGNITION TIMING
Base (initial) ignition timing is NOT adjustable on any of the 2.5L 4 cylinder or 4.0L 6 cylinder engines. Do not attempt to adjust ignition timing by rotating the distributor.
Do not attempt to modify the distributor housing to get distributor rotation. Distributor position will have no effect on ignition timing.
All ignition timing functions are controlled by the powertrain control module (PCM). Refer to On-Board
Diagnostics in the Multi-Port Fuel Injection—General Diagnosis section of Group 14, Fuel Systems for more information. Also refer to the appropriate Powertrain Diagnostics Procedures service manual for operation of the DRB Scan Tool.
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
TEST
To perform a complete test of this sensor and its circuitry, refer to the DRB scan tool. Also refer to the appropriate Powertrain Diagnostics Procedures manual. To test the sensor only, refer to the following:
(1) Disconnect the wire harness connector from the sensor (Figs. 18 or 19).
Fig. 19 Air Temperature Sensor—4.0L Engine
SENSOR RESISTANCE (OHMS)
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Fig. 18 Air Temperature Sensor—2.5L Engine
(2) Test the resistance of the sensor with a input impedance (digital) volt-ohmmeter. Do not remove the sensor from the engine for testing. For resistance values, refer to the Sensor Resistance chart. Replace the sensor if it is not within the range of resistance specified in the chart.
(3) Test the resistance of the wire harness. This is done between the Powertrain Control Module (PCM) wire harness connector terminal-21 and the sensor connector terminal. Also check continuity between terminal-4 to the sensor connector terminal. Repair the wire harness as necessary if the resistance is greater than 1 ohm.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
TEST
To perform a complete test of this sensor and its circuitry, refer to the DRB scan tool. Also refer to the appropriate Powertrain Diagnostics Procedures manual. To test the sensor only, refer to the following:
The MAP sensor is located on the cowl panel near the rear of the engine cylinder head (valve) cover
(Fig. 20).
(1) Inspect the sensor vacuum hose connections at the throttle body and sensor (Fig. 20). Repair as necessary.
CAUTION: When testing the sensor, be sure that the harness wires are not damaged by the test meter probes.
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IGNITION SYSTEMS 8D - 15
(5) Test the sensor ground circuit at sensor connector terminal-A and PCM connector terminal-4. Repair the wire harness if necessary.
(6) Test the sensor ground circuit at the PCM connector between terminal-4 and terminal-11 with an ohmmeter. If the ohmmeter indicates an open circuit, inspect for a defective sensor ground connection. Refer to Group 8W, Wiring for location of ground connection. If the ground connection is good, replace the
PCM. If terminal-4 has a short circuit to 12 volts, correct this condition before replacing the PCM.
Fig. 20 MAP Sensor—Typical
(2) Test the sensor output voltage at the sensor connector between terminals A and B as marked on the sensor body (Fig. 21). This is done with the ignition switch ON and the engine OFF. Output voltage should be 4-to-5 volts. The voltage should drop to
1.5-to-2.1 volts with a hot, neutral idle speed condition.
POWERTRAIN CONTROL MODULE (PCM)
The PCM (formerly called the SBEC or engine controller) is located in the engine compartment behind the windshield washer fluid tank on YJ models (Fig.
22). It is located in the engine compartment next to the air cleaner on XJ models (Fig. 23).
Fig. 22 PCM Location—YJ Models
Fig. 21 MAP Sensor Test—Typical
(3) Test Powertrain Control Module (PCM) terminal-1 for the same voltage described above to verify the wire harness condition. Repair as necessary.
(4) Test sensor supply voltage at sensor connector between terminals A and C with the ignition ON.
The voltage should be approximately 5 volts ( 6 0.5V).
Five volts ( 6 0.5V) should also be at terminal-6 of the corresponding Powertrain Control Module (PCM) wire harness connector. Repair or replace the wire harness as necessary.
Fig. 23 PCM Location—XJ Models
The ignition system is controlled by the PCM.
For removal and installation of this component, refer to the Component Removal/Installation section of this group.
8D - 16 IGNITION SYSTEMS
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For diagnostics, refer to the appropriate Powertrain
Diagnostic Procedures service manual for operation of the DRB scan tool.
SPARK PLUGS
For spark plug removal, cleaning, gap adjustment and installation, refer to the Component Removal/Installation section of this group.
Faulty carbon and/or gas fouled plugs generally cause hard starting, but they will clean up at higher engine speeds. Faulty plugs can be identified in a number of ways: poor fuel economy, power loss, decrease in engine speed, hard starting and, in general, poor engine performance.
Remove the spark plugs and examine them for burned electrodes and fouled, cracked or broken porcelain insulators. Keep plugs arranged in the order in which they were removed from the engine. An isolated plug displaying an abnormal condition indicates that a problem exists in the corresponding cylinder. Replace spark plugs at the intervals recommended in the maintenance chart in Group 0, Lubrication and Maintenance.
Spark plugs that have low mileage may be cleaned and reused if not otherwise defective. Refer to the following Spark Plug Condition section of this group.
CONDITION
NORMAL OPERATING
The few deposits present on the spark plug will probably be light tan or slightly gray in color. This is evident with most grades of commercial gasoline
(Fig. 24). There will not be evidence of electrode burning. Gap growth will not average more than approximately 0.025 mm (.001 in) per 1600 km (1000 miles) of operation. Spark plugs that have normal wear can usually be cleaned, have the electrodes filed, have the gap set and then be installed.
Some fuel refiners in several areas of the United
States have introduced a manganese additive (MMT) for unleaded fuel. During combustion, fuel with
MMT causes the entire tip of the spark plug to be coated with a rust colored deposit. This rust color can be misdiagnosed as being caused by coolant in the combustion chamber. Spark plug performance is not affected by MMT deposits.
COLD FOULING/CARBON FOULING
Cold fouling is sometimes referred to as carbon fouling. The deposits that cause cold fouling are basically carbon (Fig. 24). A dry, black deposit on one or two plugs in a set may be caused by sticking valves or defective spark plug cables. Cold (carbon) fouling of the entire set of spark plugs may be caused by a clogged air filter or repeated short operating times (short trips).
ELECTRODE GAP BRIDGING
Electrode gap bridging may be traced to loose deposits in the combustion chamber. These deposits accumulate on the spark plugs during continuous stopand-go driving.
When the engine is suddenly subjected to a high torque load, deposits partially liquefy and bridge the gap between electrodes (Fig. 25).
This short circuits the electrodes. Spark plugs with electrode gap bridging can be cleaned using standard procedures.
Fig. 24 Normal Operation and Cold (Carbon) Fouling
Fig. 25 Electrode Gap Bridging
SCAVENGER DEPOSITS
Fuel scavenger deposits may be either white or yellow (Fig. 26). They may appear to be harmful, but this is a normal condition caused by chemical additives in certain fuels. These additives are designed to change the chemical nature of deposits and decrease spark plug misfire tendencies. Notice that accumulation on the ground electrode and shell area may be heavy, but the deposits are easily removed. Spark
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IGNITION SYSTEMS 8D - 17
plugs with scavenger deposits can be considered normal in condition and can be cleaned using standard procedures.
temperature ranges. This depends upon the thickness and length of the center electrodes porcelain insulator.)
Fig. 26 Scavenger Deposits
CHIPPED ELECTRODE INSULATOR
A chipped electrode insulator usually results from bending the center electrode while adjusting the spark plug electrode gap. Under certain conditions, severe detonation can also separate the insulator from the center electrode (Fig. 27). Spark plugs with this condition must be replaced.
Fig. 28 Preignition Damage
SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center electrode insulator that also appears blistered (Fig.
29). The increase in electrode gap will be considerably in excess of 0.001 inch per 1000 miles of operation. This suggests that a plug with a cooler heat range rating should be used. Over advanced ignition timing, detonation and cooling system malfunctions can also cause spark plug overheating.
Fig. 27 Chipped Electrode Insulator
PREIGNITION DAMAGE
Preignition damage is usually caused by excessive combustion chamber temperature. The center electrode dissolves first and the ground electrode dissolves somewhat latter (Fig. 28). Insulators appear relatively deposit free. Determine if the spark plug has the correct heat range rating for the engine. Determine if ignition timing is over advanced, or if other operating conditions are causing engine overheating. (The heat range rating refers to the operating temperature of a particular type spark plug.
Spark plugs are designed to operate within specific
Fig. 29 Spark Plug Overheating
SPARK PLUG SECONDARY CABLES
TESTING
Spark plug cables are sometimes referred to as secondary ignition cables or secondary wires. The cables transfer electrical current from the distributor to individual spark plugs at each cylinder. The spark plug cables are of nonmetallic construction and have a built in resistance. The cables provide suppression of radio frequency emissions from the ignition system.
8D - 18 IGNITION SYSTEMS
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Check the high-tension cable connections for good contact at the ignition coil, distributor cap towers and spark plugs. Terminals should be fully seated.
The terminals and spark plug covers should be in good condition. Terminals should fit tightly to the ignition coil, distributor cap and spark plugs. The spark plug cover (boot) of the cable should fit tight around the spark plug insulator. Loose cable connections can cause corrosion and increase resistance, resulting in shorter cable service life.
Clean the high tension cables with a cloth moistened with a nonflammable solvent and wipe dry.
Check for brittle or cracked insulation.
When testing secondary cables for damage with an oscilloscope, follow the instructions of the equipment manufacturer.
If an oscilloscope is not available, spark plug cables may be tested as follows:
CAUTION: Do not leave any one spark plug cable disconnected for longer than necessary during testing. This may cause possible heat damage to the catalytic converter. Total test time must not exceed ten minutes.
With the engine not running, connect one end of a test probe to a good ground. Start the engine and run the other end of the test probe along the entire length of all spark plug cables. If cables are cracked or punctured, there will be a noticeable spark jump from the damaged area to the test probe. The cable running from the ignition coil to the distributor cap can be checked in the same manner. Cracked, damaged or faulty cables should be replaced with resistance type cable. This can be identified by the words
ELECTRONIC SUPPRESSION printed on the cable jacket.
Use an ohmmeter to test for open circuits, excessive resistance or loose terminals. Remove the distributor cap from the distributor. Do not remove
cables from cap. Remove cable from spark plug.
Connect ohmmeter to spark plug terminal end of cable and to corresponding electrode in distributor cap.
Resistance should be 250 to 1000 Ohms per inch of cable. If not, remove cable from distributor cap tower and connect ohmmeter to the terminal ends of cable.
If resistance is not within specifications as found in the Spark Plug Cable Resistance chart, replace the cable. Test all spark plug cables in this manner.
SPARK PLUG CABLE RESISTANCE
To test ignition coil-to-distributor cap cable, do not remove the cable from the cap. Connect ohmmeter to rotor button (center contact) of distributor cap and terminal at ignition coil end of cable. If resistance is not within specifications as found in the Spark Plug
Cable Resistance chart, remove the cable from the distributor cap. Connect the ohmmeter to the terminal ends of the cable. If resistance is not within specifications as found in the Spark Plug Cable
Resistance chart, replace the cable. Inspect the ignition coil tower for cracks, burns or corrosion.
For removal and installation of spark plug cables, refer to Spark Plug Secondary Cables in the Component Removal/Installation section.
THROTTLE POSITION SENSOR TEST
To perform a complete test of this sensor and its circuitry, refer to the DRB scan tool. Also refer to the appropriate Powertrain Diagnostics Procedures manual. To test the sensor only, refer to the following:
The throttle position sensor can be tested with a digital voltmeter. The center terminal of the sensor connector is the output terminal (Figs. 30 or 31).
Fig. 30 Sensor—2.5L Engine
Fig. 31 Sensor—4.0L Engine
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IGNITION SYSTEMS 8D - 19
With the ignition key in the ON position and engine not running, check the sensor output voltage at the center terminal wire of the connector. Check this at idle (throttle plate closed) and at wide open throttle (WOT). At idle, sensor output voltage should be greater than 200 millivolts. At wide open throttle, sensor output voltage must be less than 4.8 volts.
The output voltage should increase gradually as the throttle plate is slowly opened from idle to WOT.
OXYGEN SENSOR TESTS
For diagnosis, removal or installation, refer to
Group 14, Fuel Systems in this manual.
ON-BOARD DIAGNOSTICS (OBD)
FOR IGNITION SYSTEM COMPONENTS
The powertrain control module (PCM) has been programmed to monitor certain ignition system circuits:
EXAMPLE:
If a reference signal is not being detected during engine cranking from the crankshaft position sensor, a Diagnostic Trouble Code (DTC) number 11 can be observed at the Check Engine Lamp.
If the problem is sensed in a monitored circuit often enough to indicate an actual problem, a DTC is stored. The DTC will be stored in the PCM memory for eventual display to the service technician. If the problem is repaired or ceases to exist, the PCM cancels the DTC after 51 engine starts.
Certain criteria must be met for a DTC to be entered into PCM memory. The criteria may be a specific range of engine rpm, engine temperature and/or input voltage to the PCM.
A DTC indicates that the PCM has recognized an abnormal signal in a circuit or the system. A DTC may indicate the result of a failure, but never identify the failed component directly.
It is possible that a DTC for a monitored circuit may not be entered into memory even though a malfunction has occurred. Refer to On-Board Diagnostics
(OBD) in Group 14, Fuel Systems for additional information.
ACCESSING DIAGNOSTIC TROUBLE CODES
A stored Diagnostic Trouble Code (DTC) can be displayed by cycling the ignition key On-Off-On-Off-On within three seconds and observing the Malfunction
Indicator Lamp. This lamp was formerly referred to as the Check Engine Lamp. The lamp is located on the instrument panel.
They can also be displayed through the use of the
Diagnostic Readout Box (DRB) scan tool. The DRB connects to the data link connector in the engine compartment (Figs. 32 or 33). For operation of the
DRB, refer to the appropriate Powertrain Diagnostic
Procedures service manual.
Fig. 32 Data Link Connector—YJ Models—Typical
Fig. 33 Data Link Connector—XJ Models—Typical
EXAMPLES:
•
If the lamp flashes 1 time, pauses and flashes 1 more time, a flashing Diagnostic Trouble Code (DTC) number 11 is indicated.
• If the lamp flashes 3 times, pauses and flashes 5 more times, a flashing Diagnostic Trouble Code
(DTC) number 35 is indicated.
After any stored DTC information has been observed, the display will end with a flashing DTC number 55. This will indicate the end of all stored information.
ERASING TROUBLE CODES
After the problem has been repaired, the DRB scan tool must be used to erase a DTC. Refer to the appropriate Powertrain Diagnostic Procedures service manual for operation of the DRB scan tool.
8D - 20 IGNITION SYSTEMS
COMPONENT REMOVAL/INSTALLATION
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INDEX
page
Automatic Shut Down (ASD) Relay
Camshaft Position Sensor
. . . . . . . . . . . . . . . . . . 20
Crankshaft Position Sensor
. . . . . . . . . . . . . . . . . 21
Distributor
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Engine Coolant Temperature Sensor
General Information
. . . . . . . . . . . . . . . . . . . . . . . 20
Ignition Coil
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
page
Intake Manifold Air Temperature Sensor
Manifold Absolute Pressure (MAP) Sensor
Oxygen (O2S) Sensor
. . . . . . . . . . . . . . . . . . . . . 28
Powertrain Control Module (PCM)
Spark Plug Secondary Cables
. . . . . . . . . . . . . . . 29
Spark Plugs
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Throttle Position Sensor (TPS)
. . . . . . . . . . . . . . 29
GENERAL INFORMATION
This section of the group, Component Removal/Installation, will discuss the removal and installation of ignition system components.
For basic ignition system diagnostics and service adjustments, refer to the Diagnostics/Service Procedures section of this group.
For system operation and component identification, refer to the Component Identification/System Operation section of this group.
AUTOMATIC SHUT DOWN (ASD) RELAY
The ASD relay is installed in the Power Distribution Center (PDC) (Fig. 1). Relay location is printed on the PDC cover.
Fig. 1 PDC—XJ Models
REMOVAL
(1) Remove the PDC cover.
(2) Remove the relay by lifting straight up.
INSTALLATION
(1) Check the condition of relay wire terminals at
PDC before installing relay. Repair as necessary.
(2) Push the relay into the connector.
(3) Install the relay cover.
Fig. 2 PDC—YJ Models
CAMSHAFT POSITION SENSOR
The camshaft position sensor is located in the distributor.
REMOVAL
(1) Remove the distributor. Refer to Distributor
Removal.
(2) Remove the distributor rotor.
CAUTION: Do not position the distributor in a vise when removing or installing the drive gear roll pin.
Support the distributor with wooden blocks.
(3) Mark the position of the gear and the shaft in line with the roll pin. The gear MUST be installed back to its original position on the distributor shaft.
(4) Using a small pin punch and hammer, remove the distributor gear roll (spring) pin (Fig. 3).
(5) Lightly tap the end of the distributor shaft until distributor gear and thrust washer are removed.
(6) Slide the distributor shaft out of the distributor housing.
(7) Remove the camshaft position sensor mounting screw and positioning arm (Fig. 4).
(8) Slide the wire harness grommet out of the distributor housing. Remove the camshaft position sensor.
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Fig. 3 Distributor Gear—Removal/Installation
IGNITION SYSTEMS 8D - 21
transmission bellhousing at the left/rear side of the engine block (Figs. 5, 6 or 7).
On all 2.5L and 4.0L engines (except YJ models with an automatic transmission and 4.0L engine) the sensor is attached with two bolts. The 2.5L engine, when equipped with an automatic transmission, will have the sensor mounted with two nuts.
On YJ models with a 4.0L engine and automatic transmission, the sensor uses a single slotted hole to adjust its depth. A paper/cardboard type spacer with self-adhesive (Fig. 7) is attached to the bottom of the sensor to set this depth. After the engine has been started (and after sensor installation), this temporary spacer will be sheared off. New factory replacement sensors are equipped with this spacer. If the original sensor is to be reinstalled, such as with transmission and/or flywheel removal, a new spacer MUST be installed.
Fig. 5 Crankshaft Position Sensor—2.5L
Engine—Typical
Fig. 4 Camshaft Position Sensor
INSTALLATION
(1) Position the camshaft position sensor in the distributor housing. Place the wire harness grommet into the opening in the distributor housing.
(2) Install retaining arm and retaining screw.
(3) Install distributor shaft into distributor housing. Make sure the upper thrust washer is installed on the shaft.
(4) Position thrust washer and drive gear on distributor shaft.
(5) Note the previous CAUTION and install distributor drive gear roll pin.
(6) Install rotor.
(7) Install distributor.
CRANKSHAFT POSITION SENSOR
The crankshaft position sensor is mounted in the
Fig. 6 Crankshaft Position Sensor—4.0L Engine—All
Except YJ models With Automatic Transmission
8D - 22 IGNITION SYSTEMS
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If original sensor is being reinstalled (such as with transmission or flywheel removal), clean bottom of the sensor before installation. Obtain a new spacer and remove the paper backing. Install the self-adhesive side to bottom of sensor. This spacer MUST be installed. If spacer is not installed, sensor will be damaged when engine is started.
(2) Position sensor to transmission bellhousing and install mounting bolt finger tight.
(3) Gently seat (push down) the sensor until the paper spacer contacts the outer edge of the flywheel.
(4) Tighten sensor mounting bolt (Fig. 7) to 17to-21 N z m (13-to-16 ft. lbs.) torque.
(5) Connect the electrical connector to sensor.
(6) Install the clip to sensor wire harness.
(7) Install clip over fuel rail mounting stud. Install clip mounting nut.
ENGINE COOLANT TEMPERATURE SENSOR
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR. RE-
FER TO GROUP 7, COOLING.
Fig. 7 Crankshaft Position Sensor—4.0L Engine—YJ models With Automatic Transmission
REMOVAL—ALL ENGINES
(1) Near the rear of the intake manifold, disconnect the pigtail harness (on the sensor) from the main electrical harness.
(2) Remove the nut holding sensor wire clip to fuel rail mounting stud.
(3) Depending upon application, remove either the sensor mounting bolt(s) or nuts.
(4) Remove the sensor.
(5) Remove clip from sensor wire harness.
INSTALLATION—ALL EXCEPT YJ MODELS
WITH 4.0L ENGINE AND AUTOMATIC
TRANSMISSION
(1) Install the sensor flush against the opening in the transmission housing.
(2) Install and tighten the two sensor mounting bolts (or nuts) to 19 N z m (14 ft. lbs.) torque.
CAUTION: On some models, two bolts used to secure the sensor to the transmission. These bolts are specially machined to correctly space the unit to the flywheel. Do not attempt to install any other bolts.
(3) Connect the electrical connector to the sensor.
(4) Install clip on sensor wire harness.
(5) Install clip over fuel rail mounting stud. Install clip mounting nut.
INSTALLATION—YJ MODELS WITH 4.0L
ENGINE AND AUTOMATIC TRANSMISSION
(1) Be sure the paper/cardboard spacer (Fig. 7) has been installed to the bottom of the new sensor.
REMOVAL
The sensor is installed in the thermostat housing
(Fig. 8).
Fig. 8 Coolant Temperature Sensor—Typical
(1) Drain cooling system until the coolant level is below the cylinder head. For cooling system draining, refer to Group 7, Cooling.
(2) Disconnect the coolant temperature sensor wire connector.
(3) Remove the sensor from the thermostat housing (Fig. 8).
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IGNITION SYSTEMS 8D - 23
INSTALLATION
(1) Install coolant temperature sensor into the thermostat housing. Tighten to 28 N z m (21 ft. lbs.) torque.
(2) Connect the wire connector.
(3) Fill the cooling system. Refer to group 7, Cooling System.
DISTRIBUTOR
All distributors contain an internal oil seal that prevents oil from entering the distributor housing.
The seal is not serviceable.
The camshaft position sensor is located in the distributor on all engines (Fig. 9).
Refer to Fig. 9 for an exploded view of the distributor.
Fig. 9 Distributor—2.5L/4.0L Engines—Typical
REMOVAL—2.5L ENGINE
(1) Disconnect the negative battery cable at the battery.
(2) Disconnect coil secondary cable at coil.
(3) Remove distributor cap from distributor (2 screws). Do not remove cables from cap.
(4) Disconnect the distributor wiring harness from the main engine harness.
(5) Scribe a mark on the distributor housing in line with the tip of the rotor. Note the position of the rotor and distributor housing. This is in relation to the surrounding engine components as reference points for installing the distributor.
(6) Remove the distributor holddown bolt and clamp.
(7) Remove the distributor from engine by lifting straight up. Remove and discard old distributor-toengine block gasket. Note that the rotor will rotate slightly in a counterclockwise direction while lifting up the distributor. Note this position after removal.
INSTALLATION—2.5L ENGINE
ENGINE NOT ROTATED AFTER REMOVAL
This procedure assumes that the engine was not rotated with distributor out of engine.
(1) Clean the distributor mounting hole area of the engine block.
(2) Install a new distributor-to-engine block gasket.
There is a fork on the distributor housing where the housing seats against the engine block. The slot in the fork aligns with the distributor holddown bolt hole in the engine block. The distributor is correctly installed when the rotor is correctly positioned. This is with the slot in the fork aligned with the holddown bolt hole in the cylinder block. Because of the fork on the distributor housing, initial ignition timing is not adjustable (the distributor cannot be rotated).
(3) Position the distributor shaft in the cylinder block. If the engine was not rotated while the distributor was removed, perform the following:
• Align the rotor tip with the scribe mark on the distributor housing during removal. Turn the rotor approximately 1/8-turn counterclockwise past the scribe mark.
CAUTION: Be sure that the distributor shaft fully engages into the oil pump drive gear shaft. It may be necessary to slightly rotate (bump) the engine.
This is done while applying downward hand force on the distributor body. It should fully engage the distributor shaft with the oil pump drive gear shaft.
• Slide the distributor shaft down into the engine.
It may be necessary to move the rotor and shaft
(slightly) to engage the distributor shaft with the slot in the oil pump shaft. The same may have to be done to engage the distributor gear with the camshaft gear. However, the rotor should align with the scribe mark when the distributor shaft is down in place.
• Install the distributor holddown clamp and bolt.
Tighten the bolt to 23 N z m (17 ft. lbs.) torque.
(4) Install the distributor cap (with the ignition cables) on the distributor housing (Fig. 10). Tighten distributor cap holddown screws to 3 N z m (26 in. lbs.) torque.
(5) Connect the distributor wiring harness to the main engine harness.
8D - 24 IGNITION SYSTEMS
J mark (0 degree) on timing degree scale. Always rotate the engine in direction of normal rotation. Do not turn the engine backward to align the timing marks.
• Using a flat blade screwdriver, rotate the oil pump gear. Do this to position the gear slot on the oil pump shaft slightly before the 11 o’clock position
(Fig. 11).
• With the distributor cap removed, install the distributor with the rotor located just past the 2 o’clock position (Fig. 12).
Fig. 10 Spark Plug Cable Positions—2.5L Engine
CAUTION: Do not puncture the spark plug cables or boots to make the connection. Use proper adapters.
(6) Connect battery cable to battery.
ENGINE ROTATED AFTER REMOVAL
There is a fork on the distributor housing where the housing seats against the engine block. The slot in the fork aligns with the hole for the distributor holddown bolt in the engine block. The distributor is correctly installed when the rotor is correctly positioned. This is when the slot in the fork is aligned with the hole for the distributor holddown bolt in the cylinder block. Because of the fork on the distributor housing, initial ignition timing is not adjustable (the distributor cannot be rotated).
(1) If the engine was rotated while the distributor was removed, it will be necessary to establish timing according to following procedure:
• Remove the No. 1 spark plug. Hold a finger over the spark plug hole and rotate the engine until compression pressure is felt. Slowly continue to rotate the engine. Do this until the timing index on vibration damper pulley aligns with top dead center (TDC)
Fig. 11 Align Oil Pump Gear Slot—2.5L Engine
Fig. 12 Distributor Installation—2.5L Engine
• When distributor is fully engaged in its correct location, the rotor should be just past the 3 o’clock position (Fig. 13).
• Install the distributor holddown clamp and bolt.
Tighten the holddown bolt to 23 N z m (17 ft. lbs.) torque.
CAUTION: If the distributor cap is incorrectly positioned on distributor housing, the cap or rotor may be damaged when engine is started.
(2) Install the distributor cap (with ignition cables) on the distributor housing. Be sure that the cap fits securely on rim of the distributor housing.
(3) Connect the distributor wiring harness to the main engine harness.
CAUTION: Do not puncture the spark plug cables or boots to make the connection. Use proper adapters.
REMOVAL—4.0L ENGINE
The distributor used in the 4.0L engine contains an internal oil seal that prevents oil from entering the distributor housing. The seal is not serviceable.
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IGNITION SYSTEMS 8D - 25
Fig. 13 Distributor Rotor Position—2.5L Engine
The camshaft position sensor is located in the distributor on all engines (Fig. 9).
Refer to figure 9 for an exploded view of the distributor.
(1) Disconnect the negative battery cable at battery.
(2) On XJ models equipped with A/C, remove the electrical cooling fan and shroud assembly from the radiator. This will provide room to turn the engine with a socket and ratchet using the vibration damper bolt.
(3) Scribe a mark on the distributor housing. Do this below the left side of (past) the number one spark plug cable post of the distributor cap. This will be used as a reference for #1 cylinder firing position
(Fig. 14).
(4) Remove the distributor cap from distributor (2 screws).
(5) Turn the engine in a clockwise direction until the rotor is approaching the scribe mark on the distributor housing. Then slowly turn the engine until the timing mark on the crankshaft vibration damper lines up with zero on the front cover timing scale
(Fig. 15).
The timing mark is on the edge of the vibration damper closest to the engine front cover.
(6) Align the trailing edge of the rotor blade with the scribe mark on the distributor housing (Fig. 16).
(7) Remove the distributor holddown bolt and clamp.
(8) Remove the distributor from the engine by lifting straight up. Remove and discard old distributorto-engine block gasket. Note that the rotor will
Fig. 14 Mark Distributor Housing
Fig. 15 Align Timing Marks rotate slightly in a counterclockwise direction while lifting up the distributor. Note this position after removal.
INSTALLATION—4.0L ENGINE
(1) Clean the distributor mounting area of the cylinder block.
(2) Install a replacement distributor-to-engine block gasket.
(3) Using a flat blade screwdriver, turn the oil pump gear shaft. Do this until the slot is slightly past the 11 o’clock position (Fig. 17).
8D - 26 IGNITION SYSTEMS
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Fig. 16 Align Rotor Trailing Edge With Scribe Mark
The oil pump shaft is located down in the distributor hole.
Fig. 18 Distributor Installation—Typical
Fig. 17 Align Oil Pump Gear Shaft—4.0L Engine
(4) Install the rotor.
(5) Without engaging the distributor gear into the cam gear, position the distributor into the hole in the engine block. Be sure the distributor gasket is installed.
(6) Visually line up the holddown ear of the distributor housing with the holddown clamp hole (Fig.
18).
(7) Turn the rotor to the 4 o’clock position (Fig.
19).
(8) Slide the distributor down into the block until it seats. Keep the holddown ear aligned to the hole in the block.
(9) The rotor should be in the 5 o’clock position.
This is with the trailing edge of rotor blade lined up with scribe mark on distributor housing (number one spark plug cable post location).
Fig. 19 Rotor Alignment
(10) Install the distributor holddown clamp bolt and tighten to 23 N z m (17 ft. lbs.) torque.
(11) Install the distributor cap and connect the distributor electrical connector.
(12) Install electrical cooling fan and shroud if applicable.
(13) Connect battery cable to battery.
IGNITION COIL
The ignition coil is an epoxy filled type. If the coil is replaced, it must be replaced with the same type.
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REMOVAL
The ignition coil is mounted to the right side of the engine block next to the distributor (Fig. 20).
IGNITION SYSTEMS 8D - 27
Fig. 20 Ignition Coil—Typical
(1) Disconnect the ignition coil secondary cable from ignition coil (Fig. 20).
(2) Disconnect engine harness connector from ignition coil.
(3) Remove ignition coil mounting bolts. Remove coil.
INSTALLATION
(1) Install ignition coil to bracket on cylinder block with mounting bolts.
(2) Connect engine harness connector to coil.
(3) Connect ignition coil cable to ignition coil.
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
REMOVAL
The intake manifold air temperature sensor is installed into the intake manifold plenum (Figs. 21 or
22).
Fig. 22 Air Temperature Sensor—4.0L Engine
(1) Disconnect the electrical connector from the sensor.
(2) Remove the sensor from the intake manifold.
INSTALLATION
(1) Install the air temperature sensor into the intake manifold. Tighten the sensor to 13 N z m (10 ft.
lbs.) torque.
(2) Connect the electrical connector to the sensor.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
The MAP sensor is located on the dash panel near the rear of the engine cylinder head (valve) cover
(Fig. 23).
Fig. 21 Air Temperature Sensor—2.5L Engine
Fig. 23 MAP Sensor—Typical
REMOVAL
(1) Disconnect the MAP sensor electrical connector
(Fig. 23).
(2) Disconnect the MAP sensor vacuum supply hose (Fig. 23).
(3) Remove the MAP sensor mounting nuts and remove MAP sensor.
8D - 28 IGNITION SYSTEMS
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INSTALLATION
(1) Install MAP sensor to dash panel and secure with mounting nuts.
(2) Install the MAP sensor vacuum supply hose.
(3) Connect the MAP sensor electrical connector.
OXYGEN (O2S) SENSOR
For diagnostics and removal/installation procedures, refer to Group 14, Fuel Systems, in this manual.
POWERTRAIN CONTROL MODULE (PCM)
The PCM was formerly referred to as the SBEC or engine controller.
XJ MODELS
On XJ models, the PCM is located in the engine compartment next to the air cleaner (Fig. 24).
Fig. 24 PCM Location—XJ Models
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Loosen 60-way connector mounting screw until connector can be disengaged from PCM.
(3) Pull 60-way connector straight back from PCM.
(4) Remove PCM mounting bolts.
(5) Remove PCM from vehicle.
INSTALLATION
(1) Check the pins in the PCM 60-way electrical connector for damage. Repair as necessary.
(2) Install PCM. Tighten mounting bolts to 1 N z m
(9 in. lbs.) torque.
(3) Engage 60-way connector into PCM. Tighten connector mounting screw to 4 N z m (35 in. lbs.) torque.
(4) Connect battery cable to battery.
YJ MODELS
On YJ models, the PCM is located in the engine compartment behind the windshield washer fluid reservoir (Fig. 25).
Fig. 25 PCM Location—YJ Models
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Remove windshield washer fluid reservoir.
(3) Loosen 60-way connector mounting screw until connector can be disengaged from PCM.
(4) Pull 60-way connector straight back from PCM.
(5) Remove PCM mounting bolts.
(6) Remove PCM from vehicle.
INSTALLATION
(1) Check the pins in the PCM 60-way electrical connector for damage. Repair as necessary.
(2) Install PCM. Tighten mounting bolts to 1 N z m
(9 in. lbs.) torque.
(3) Engage 60-way connector into PCM. Tighten connector mounting screw to 4 N z m (35 in. lbs.) torque.
(4) Connect battery cable to battery.
(5) Install washer fluid reservoir.
SPARK PLUGS
PLUG REMOVAL
(1) Always remove spark plug or ignition coil cables by grasping at the cable boot. Turn the cable boot 1/2 turn and pull straight back in a steady motion. Never pull directly on the cable. Internal damage to cable will result.
(2) Prior to removing the spark plug, spray compressed air around the spark plug hole and the area around the spark plug. This will help prevent foreign material from entering the combustion chamber.
(3) Remove the spark plug using a quality socket with a rubber or foam insert.
(4) Inspect the spark plug condition. Refer to
Spark Plugs in the Diagnostics/Service Procedures section of this group.
PLUG CLEANING
The plugs may be cleaned using commercially available spark plug cleaning equipment. After
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IGNITION SYSTEMS 8D - 29
cleaning, file the center electrode flat with a small point file or jewelers file before adjusting gap.
PLUG GAP ADJUSTMENT
Check the spark plug gap with a gap gauge tool. If the gap is not correct, adjust it by bending the ground electrode (Fig. 26). Never attempt to adjust the gap by bending the center electrode.
SPARK PLUG GAP
• 2.5L Engine Spark Plug Gap: .89 mm (.035 in).
• 4.0L Engine Spark Plug Gap: .89 mm (.035 in).
the rubber boot slightly (1/2 turn) to break it loose.
Grasp the boot (not the cable) and pull it off with a steady, even force.
Install cables into the proper engine cylinder firing order (Figs. 27 or 28).
Fig. 27 Engine Firing Order—2.5L Engine
Fig. 26 Setting Spark Plug Gap—Typical
PLUG INSTALLATION
Always tighten spark plugs to the specified torque.
Over tightening can cause distortion. This may result in a change in the spark plug gap.
When replacing the spark plug and ignition coil cables, route the cables correctly and secure them in the appropriate retainers. Failure to route the cables properly can cause the radio to reproduce ignition noise. It could cause cross ignition of the spark plugs, or short circuit the cables to ground.
(1) Start the spark plug into the cylinder head by hand to avoid cross threading.
(2) Tighten the spark plugs to 35-41 N z m (26-30 ft.
lbs.) torque.
(3) Install spark plug cables over spark plugs.
SPARK PLUG SECONDARY CABLES
CAUTION: When disconnecting a high voltage cable from a spark plug or from the distributor cap, twist
Fig. 28 Engine Firing Order—4.0L Engine
When replacing the spark plug and coil cables, route the cables correctly and secure in the proper retainers. Failure to route the cables properly can cause the radio to reproduce ignition noise. It could also cause cross ignition of the plugs, or short circuit the cables to ground.
When installing new cables, make sure a positive connection is made. A snap should be felt when a good connection is made between the plug cable and the distributor cap tower.
THROTTLE POSITION SENSOR (TPS)
For diagnostics and removal/installation procedures, refer to Group 14, Fuel Systems, in this manual.
8D - 30 IGNITION SYSTEMS
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IGNITION SWITCH
INDEX
page
General Information
. . . . . . . . . . . . . . . . . . . . . . . 30
Ignition Switch Installation/Adjustment
page
Ignition Switch Removal
. . . . . . . . . . . . . . . . . . . 30
Ignition Switch Testing
. . . . . . . . . . . . . . . . . . . . . 30
GENERAL INFORMATION
The ignition switch is mounted (under the instrument panel) on the lower section of the steering column. The headlamp dimmer switch is mounted beside the ignition switch (Fig. 1). Both of these switches (ignition and dimmer) share the same mounting screws.
The switch is connected to the ignition key lock assembly by a remote actuator rod. This remote actuator rod fits into an access hole on the bottom of the ignition switch (Fig. 2).
Fig. 1 Ignition Switch/Headlamp Dimmer
Switch—Typical
IGNITION SWITCH REMOVAL
(1) Disconnect the negative battery cable at the battery.
(2) XJ models: Remove the lower instrument panel trim assembly. YJ models: Remove the windshield wiper intermittent control module and its bracket (if equipped).
(3) Place the ignition key lock in ACCESSORY position.
(4) Remove the two headlamp dimmer switch attaching nuts. Lift the switch from steering column while disengaging actuator rod.
Fig. 2 Ignition Switch/Remote Actuator
Rod—Typical
Before removing dimmer switch, tape the two remote control actuator rods (ignition switch and dimmer) to the steering column. This will prevent accidental disengagement from the upper part of the steering column.
(5) Remove the ignition switch-to-steering column attaching screws.
(6) Disengage the ignition switch from the remote actuator rod by lifting straight up. Remove switch from steering column.
(7) Remove wiring from switch as follows:
Two electrical connectors are used to connect all wiring to the ignition switch. One of the connectors is installed (interlocked) over the top of the other connector. Remove wiring from switch by disconnecting the (black) harness connector first and then the other connector. Remove the switch from the vehicle.
IGNITION SWITCH TESTING
To test the ignition switch circuity and continuity, proceed as follows. Place the slide bar (on the ignition switch) (Fig. 2) into the detent position to be tested. An ohmmeter or continuity light may be used to check switch continuity. Refer to the Ignition
J
Switch Continuity Tests chart for continuity tests.
Refer to (Fig. 3) for the lettered/numbered terminal positions. All wiring must be disconnected from the ignition switch before performing any continuity testing.
There are five positions on the ignition switch. The switch positions (in order) are: ACCESSORY, OFF-
LOCK, OFF, ON AND START (Figs. 4 or 5). Each position has a detent stop (except START), which is spring loaded to release when the key is released.
The maximum voltage drop between any two connected terminals should not exceed 12.5 millivolts per amp. For example: If a 10 amp load is drawn through the switch, maximum voltage drop should be
10 x 0.0125 or 0.125 volt.
IGNITION SWITCH CONTINUITY TESTS
IGNITION SYSTEMS 8D - 31
IGNITION SWITCH INSTALLATION/ADJUSTMENT
(1) Place the key lock switch in the ACCESSORY position.
(2) Place the slider bar (in the ignition switch)
(Fig. 2) into the ACCESSORY detent position.
(3) Connect the wiring to the switch as follows: Install the non-black (colored) connector first and then the black (colored) connector to the ignition switch.
One connector will interlock the other connector.
(4) Slip the remote actuator rod into the access hole on the switch (Fig. 2). Install the switch to the steering column. Be careful not to move the slider bar (on the switch) out of the ACCESSORY detent position. Remove the ignition switch actuator rod securing-tape from steering column.
(5) Install the two ignition switch-to-steering column screws finger tight. Do not tighten screws at this time.
(6) Adjust ignition switch as follows:
(a) Non-tilt steering column: While holding key lock switch in ACCESSORY position, gently slide ignition switch up (towards steering wheel). This will remove slack from switch. Tighten attaching
Fig. 3 Ignition Switch Terminals/Circuits screws. Do not allow the ignition switch to move from the ACCESSORY detent position.
(b) Tilt steering column: While holding the key lock switch in the ACCESSORY position, gently slide the ignition switch down (away from steering wheel) to remove slack from switch. Tighten at-
8D - 32 IGNITION SYSTEMS
taching screws. Do not allow the ignition switch to move from the ACCESSORY detent position.
Because the ignition switch and the headlamp dimmer switch share the same two mounting screws, one of the screws must be removed from the ignition switch. This must be done after the ignition switch has been adjusted and before the dimmer switch has been installed. Remove one screw. Do not remove the stud/nut.
(7) Install the headlamp dimmer switch as follows:
Slip switch into actuator rod and position over the ignition switch. Install screws finger tight. Remove the dimmer switch actuator rod securing-tape from steering column.
(8) Adjust dimmer switch as follows: Depress the switch slightly and insert a 3/32-inch drill bit into the adjustment hole (Fig. 1). This is done to prevent horizontal switch movement.
(9) Move switch toward steering wheel to remove any lash from switch actuator rod. Tighten dimmer and ignition switch fasteners to 4 N z m (35 in. lbs.) torque.
(10) XJ models: Install the lower instrument panel trim assembly. YJ models: Install the windshield wiper intermittent control module and its bracket (if equipped).
(11) Install the negative battery cable.
Test dimmer switch. Test ignition switch operation in all switch positions. If equipped with a tilt steering column, test operation of dimmer switch and ignition switch in all tilt positions.
Fig. 4 Detent Positions—Non-Tilt Steering Column
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Fig. 5 Detent Positions—Tilt Steering Column
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IGNITION SYSTEMS 8D - 33
SPECIFICATIONS
GENERAL INFORMATION
The following specifications are published from the latest information available at the time of publication. If anything differs between the specifica- tions found on the Vehicle Emission Control
Information (VECI) label and the following spec-
ifications, use specifications on VECI label. The
VECI label is located in the engine compartment.
SPARK PLUGS
ENGINE FIRING ORDER—4.0L ENGINE
ENGINE FIRING ORDER—2.5L ENGINE
TORQUE
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INSTRUMENT PANEL AND GAUGES 8E - 1
INSTRUMENT PANEL AND GAUGES
GROUP INDEX page page
INSTRUMENT PANEL AND GAUGES—XJ . . . . . 1
INSTRUMENT PANEL AND GAUGES—YJ . . . . 14
INSTRUMENT PANEL AND GAUGES—XJE
CONTENTS page
INSTRUMENT CLUSTER DIAGNOSIS
. . . . . . . . 3
INSTRUMENT CLUSTER GENERAL INFORMATION
. . 1
page
INSTRUMENT CLUSTER SERVICE PROCEDURES
. . . 5
SPECIFICATIONS
. . . . . . . . . . . . . . . . . . . . . . . 13
INSTRUMENT CLUSTER GENERAL INFORMATION
INDEX
page
4WD Indicator Lamp . . . . . . . . . . . . . . . . . . . . . . . . 2
Anti-Lock Brake Indicator Lamp
. . . . . . . . . . . . . . . 2
Brake Indicator Lamp . . . . . . . . . . . . . . . . . . . . . . . 2
Coolant Temperature Gauge
. . . . . . . . . . . . . . . . . 1
Coolant Temperature Indicator Lamp
Fuel Gauge
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Low Fuel Warning Lamp . . . . . . . . . . . . . . . . . . . . . 2
page
Malfunction Indicator Lamp (Check Engine)
Oil Pressure Gauge
. . . . . . . . . . . . . . . . . . . . . . . 1
Oil Pressure Indicator Lamp . . . . . . . . . . . . . . . . . . 1
Speedometer/Odometer System
Tachometer
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Upshift Indicator Lamp
. . . . . . . . . . . . . . . . . . . . . . 2
Voltmeter
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
With the ignition switch in the ON or START position, voltage supplied to the instrument cluster is limited by fuse #17. The voltage is supplied to all the gauges and indicator lamps through the instrument cluster printed circuit.
With the ignition switch in the OFF position, voltage is not supplied to the instrument cluster and the gauges do not indicate any vehicle condition.
VOLTMETER
The voltmeter measures battery or generator output voltage, whichever is greater.
OIL PRESSURE GAUGE
The oil pressure gauge pointer position is controlled by a magnetic field created by electrical current flow through the coils within the gauge. A change in current flow will change the magnetic field which changes the pointer position. The oil pressure sender is a variable resistor that changes electrical resistance with a change in oil pressure (values shown in Specifications chart).
OIL PRESSURE INDICATOR LAMP
Voltage is supplied to one side of the indicator bulb and the oil pressure switch is connected to the other side. When oil pressure is too low the switch closes providing a path to ground, and the indicator bulb lights.
COOLANT TEMPERATURE GAUGE
The coolant temperature gauge pointer position is controlled by a magnetic field created by electrical current flow through the coils within the gauge. A change in current flow will change the magnetic field which changes the pointer position. The coolant temperature sensor is a thermistor that changes electrical resistance with a change in coolant temperature
(values shown in Specifications chart).
COOLANT TEMPERATURE INDICATOR LAMP
Voltage is supplied to one side of the indicator bulb and the coolant temperature switch is connected to the
8E - 2 XJ INSTRUMENT PANEL AND GAUGES
J other side. When coolant temperature is too high the switch closes providing a path to ground, and the indicator bulb lights.
TACHOMETER
The tachometer displays the engine speed (RPM).
With the engine running, the tachometer receives an engine speed signal from the Powertrain Control
Module pin 43 (values shown in Specifications chart).
SPEEDOMETER/ODOMETER SYSTEM
The speedometer/odometer system consists of an electric speedometer and pushbutton reset odometer mounted in the cluster. The system also includes the wire harness from the cluster to the vehicle speed sensor at the transmission, and the adapter and pinion in the transmission. A signal is sent from a transmission mounted vehicle speed sensor to the speedometer/odometer circuitry through the wiring harness. Refer to
Group 21 - Transmission for selecting the proper pinion, and selecting and indexing the proper adapter.
FUEL GAUGE
The fuel gauge pointer position is controlled by a magnetic field created by electrical current flow through the coils within the gauge. A change in current flow will change the magnetic field which changes the pointer position. The fuel level sender is a variable resistor that changes electrical resistance with a change of the level of fuel in the tank (values shown in Specifications chart).
LOW FUEL WARNING LAMP
The low fuel warning lamp will light when the fuel level falls below approximately 4 gallons. A low fuel warning module controls when the lamp will light.
When the module senses 66.5 ohms or less from the fuel level sender for 10 continuous seconds, the lamp will light. The lamp will remain on until the module senses 63.5 ohms or more from the fuel level sender for 20 continuous seconds.
UPSHIFT INDICATOR LAMP
Vehicles equipped with manual transmissions have an optional upshift indicator lamp. The lamp is controlled by the Powertrain Control Module. The lamp lights to indicate when the driver should shift to the next highest gear for best fuel economy. The Powertrain Control
Module will turn the lamp off after 3 to 5 seconds if the upshift is not performed. The lamp will remain off until the vehicle stops accelerating and is brought back to the range of lamp operation or shifted into another gear.
The indicator lamp is normally illuminated when the ignition switch is turned ON and is turned off when the engine is started. The lamp will be lighted during engine operation according to engine speed and load.
BRAKE INDICATOR LAMP
The brake indicator lamp warns the driver that the parking brake is applied or that hydraulic pressure in the split brake system is unequal.
Voltage is supplied through the brake indicator bulb to 3 switches. A path to ground for the current is available if:
• The brake warning switch is closed (with unequal brake system hydraulic pressures), or
• The ignition switch is in the START position (to test the bulb), or
• The park brake switch is closed (with the parking brake applied).
ANTI-LOCK BRAKE SYSTEM (ABS) INDICATOR
LAMP
The anti-lock brake system (ABS) lamp lights to indicate a system self-check is in process at vehicle start-up. If light remains on after start-up or comes on and stays on while driving, it may indicate that the ABS system has detected a malfunction or has become inoperative.
4WD INDICATOR LAMP
COMMAND-TRAC 4WD
The PART TIME lamp lights when the vehicle is engaged in four-wheel drive mode. Voltage is supplied to one side of the indicator bulb. A switch in the transfer case area is connected to the other side of the indicator bulb. When the switch is closed, a path to ground is provided and the indicator bulb lights.
SELECT-TRAC 4WD
The four-wheel drive icon or FULL TIME lamp lights when the vehicle is engaged in full time fourwheel drive mode. The PART TIME lamp lights when the vehicle is in part time four-wheel drive mode.
Voltage is supplied to one side of the indicators.
Switches in the transfer case area are connected to the other side of the indicator bulbs. When a switch is closed, a path to ground is provided and the indicator bulb lights.
MALFUNCTION INDICATOR LAMP (CHECK ENGINE)
The Malfunction Indicator Lamp (Check Engine) lights each time the ignition switch is turned ON and stays on for 3 seconds as a bulb test.
If the PCM receives an incorrect signal or no signal from certain sensors or emission related systems the lamp is turned on (pin 32 of PCM). This is a warning that the PCM has recorded a system or sensor malfunction. In some cases when a diagnostic trouble code is declared the PCM will go into a limp-in mode in an attempt to keep the system operating. It signals an immediate need for service.
The lamp also can be used to display diagnostic trouble codes (DTC). Cycle the ignition switch ON,
OFF, ON, OFF, ON within 5 seconds. This will allow any trouble codes stored in the PCM memory to be displayed in a series of flashes representing digits.
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XJ INSTRUMENT PANEL AND GAUGES 8E - 3
INSTRUMENT CLUSTER DIAGNOSIS
INDEX
page
4WD Indicator Inoperative
. . . . . . . . . . . . . . . . . . . 4
Anti-Lock Indicator
. . . . . . . . . . . . . . . . . . . . . . . . . 4
Brake Indicator Inoperative
. . . . . . . . . . . . . . . . . . 4
Coolant Temperature Gauge Inoperative
Coolant Temperature Indicator Inoperative
Fuel Gauge Inoperative
. . . . . . . . . . . . . . . . . . . . . 3
Gauges and Indicators Inoperative
Instrument Panel Lamps
. . . . . . . . . . . . . . . . . . . . 4
Low Fuel Warning Inoperative
. . . . . . . . . . . . . . . . 4
Low Washer Indicator Inoperative
page
Malfunction Indicator Lamp (Check Engine)
Oil Pressure Gauge Inoperative
. . . . . . . . . . . . . . . 3
Oil Pressure Indicator Inoperative
Radio/Clock Illumination
. . . . . . . . . . . . . . . . . . . . 4
Seat Belt Indicator
. . . . . . . . . . . . . . . . . . . . . . . . 4
Speedomete/Odometer Inoperative . . . . . . . . . . . . . 3
Tachometer Inoperative
. . . . . . . . . . . . . . . . . . . . . 3
Upshift Indicator Inoperative
. . . . . . . . . . . . . . . . . 4
Voltmeter Inoperative
. . . . . . . . . . . . . . . . . . . . . . . 3
SPEEDOMETER/ODOMETER INOPERATIVE
(1) Check for continuity in the wire between the vehicle speed sensor and cluster connector pin A5.
(2) With the ignition switch in the ON position, check for battery voltage across pin A8 (B+) and pin
B2 (ground).
(3) Perform vehicle speed sensor test. Refer to the appropriate vehicle Diagnostic Test Procedures manual.
(4) If all the previous tests prove good, replace speedometer/odometer.
GAUGES AND INDICATORS INOPERATIVE
(1) Remove and inspect fuse #17. Replace as required.
(2) Measure resistance at instrument cluster connector terminal A3. Meter should read zero ohms. If not, repair open to ground.
VOLTMETER INOPERATIVE
(1) Turn ignition switch to ON. Voltmeter should read battery voltage. If not, go to step 2.
(2) Measure voltage at instrument cluster connector terminal A8. Meter should read battery voltage.
If OK, replace meter. If not, repair open to fuse #17.
OIL PRESSURE GAUGE INOPERATIVE
(1) Turn ignition switch to ON.
(2) Disconnect oil pressure sender connector (Fig.
1). Needle goes to H. If not, go to step 3.
(3) Touch oil pressure sender connector to ground.
Needle goes to L. If OK, replace sender. If not, repair open to gauge (instrument cluster connector terminal
B7).
OIL PRESSURE INDICATOR INOPERATIVE
(1) Turn ignition switch to ON.
(2) Touch oil pressure switch connector to ground.
Lamp should light. If OK, replace switch. If bulb is
OK, repair open to instrument cluster connector terminal B7.
Fig. 1 Oil Pressure Sending Unit—4.0L
COOLANT TEMPERATURE GAUGE INOPERATIVE
(1) Turn ignition switch to ON.
(2) Disconnect coolant temperature sender connector. Needle goes to C. If not, go to step 3.
(3) Touch coolant temperature sender connector to ground. Needle goes to H. If OK, replace sender. If not, repair open to gauge (instrument cluster connector terminal A1).
COOLANT TEMPERATURE INDICATOR
INOPERATIVE
(1) Turn ignition switch to ON.
(2) Touch coolant temperature indicator connector to ground. Lamp should light. If OK, replace switch.
If bulb is OK, repair open to instrument cluster connector terminal A1.
TACHOMETER INOPERATIVE
Tachometer input is from the Powertrain Control
Module pin 43. Use the DRB scan tool to test.
FUEL GAUGE INOPERATIVE
(1) Turn ignition switch to ON.
(2) Disconnect fuel gauge sender connector. Needle should go to E.
8E - 4 XJ INSTRUMENT PANEL AND GAUGES
J
(3) Connect a jumper between terminal A and B on the body half of the fuel gauge sender connector. The gauge should move to F. If gauge is OK, replace sender. If not, go to step 4.
(4) Measure resistance of sender. Meter should read 105 to 5 ohms. If OK, go to step 5. If not, replace sender.
(5) Check for an open between sender connector and gauge. If OK, replace gauge. If not, repair open to gauge.
LOW FUEL WARNING INOPERATIVE
(1) Turn ignition switch to ON.
(2) Disconnect terminal B1 of the instrument cluster connector. Wait at least 10 seconds. Lamp (LED) should light. If OK, replace sender. If not, replace low fuel warning module.
UPSHIFT INDICATOR INOPERATIVE
(1) Turn ignition switch to ON.
(2) Ground pin 7 of connector B. Lamp should light. If not, replace bulb. If OK, continue with step 3.
(3) Turn ignition switch to OFF. Check for continuity between connector B pin 2 and pin 54 of the
Powertrain Control Module. If OK, replace PCM. If not, repair open.
BRAKE INDICATOR INOPERATIVE
(1) Turn ignition switch to ON. Apply parking brake, brake warning switch connector unplugged.
(2) Jumper brake warning switch connector terminal B to ground. Lamp should light. If bulb is OK, repair open to indicator.
(3) Turn ignition switch to OFF. Measure resistance between brake warning switch connector terminal A and ground. Meter should read zero ohms. If
OK, check switch and/or brake system. If not, repair open to park brake switch ground.
4WD INDICATOR INOPERATIVE
(1) Apply parking brake, start engine, vehicle in
4WD Lock or 4WD.
(2) Unplug switch and touch harness side of wire to ground. Lamp should light. If OK, check switch operation, replace if bad. If bulb is OK, repair open to indicator.
LOW WASHER INDICATOR INOPERATIVE
(1) Turn ignition switch to ON.
(2) Jumper 12 volts to fluid level switch connector terminal B. Lamp should light. If not, go to step 3.
(3) Measure resistance between terminal B and ground. Meter should read zero ohms. If not, repair open to bulb. If OK, go to step 4.
(4) Measure voltage at fluid level switch connector terminal A. Meter should read battery voltage. If
OK, replace switch. If not, repair open to fuse.
MALFUNCTION INDICATOR LAMP (CHECK ENGINE)
(1) Turn ignition switch to ON.
(2) Jumper Powertrain Control Module terminal 2 to ground. Lamp should light. If bulb is OK, check for open to instrument cluster connector terminal 2.
ANTI-LOCK INDICATOR
(1) Turn ignition switch to ON.
(2) Jumper instrument cluster connector terminal
6 to ground. Lamp should light. If bulb is OK, check wiring for an open to module. Refer to Group 5 -
Brakes.
SEAT BELT INDICATOR
Jumper instrument cluster connector terminal 15 to 12 volts. Lamp should light. If not, replace bulb. If
OK, check wiring for an open to buzzer module. Refer to Group 8U - Chime/Buzzer Warning Systems.
RADIO/CLOCK ILLUMINATION
With the ignition switch in ACCESSORY or ON, power comes from the radio fuse. It then goes through the normally closed contacts of the radio illumination relay to the radio at connector terminal
11.
Pulling the headlamp switch to ON energizes the radio illumination relay. This closes the normally open contacts of the relay, and the brightness for the radio display is controlled by the headlamp switch rheostat. The back-lighting for the radio is also controlled by the headlamp rheostat through radio connector terminal 10.
Refer to Group 8F - Audio Systems, for radio illumination relay diagnosis.
INSTRUMENT PANEL LAMPS
Voltage is supplied at all times from the 40 amp
Maxi fuse (located in the Power Distribution Center) through the park lamps fuse to the headlamp switch.
The circuit continues through the instrument lamps fuse to the individual instrument panel lamps to ground. Lamp brightness is controlled by turning the headlamp switch knob.
DIAGNOSIS
(1) Turn parking lamps ON.
(2) Check park lamps fuse. Replace as required.
(3) Check instrument lamps fuse. Replace as required.
(4) Measure voltage at battery side of instrument lamps fuse with rheostat turned counterclockwise to clockwise (LO to HI). Meter should read zero volts to battery voltage. If not, replace headlamp switch.
(5) Measure resistance at ground side of instrument lamps fuse with parking lamps OFF. Meter should read almost zero ohms (except bulb filament).
If not, repair open to ground. If zero ohms, 12 volt supply wire from fuse is shorted to ground, repair short.
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XJ INSTRUMENT PANEL AND GAUGES 8E - 5
INSTRUMENT CLUSTER SERVICE PROCEDURES
INDEX
page
Gauge Replacement—Instrument Cluster Removed
Gear Selector Indicator Replacement—Instrument
Cluster Removed
. . . . . . . . . . . . . . . . . . . . . . . . 6
Instrument Cluster Replacement
Instrument Panel Replacement (Fig. 9)
Printed Circuit Replacement—Instrument page
Cluster Removed
. . . . . . . . . . . . . . . . . . . . . . . . 6
Speedometer Replacement—Instrument
Cluster Removed
. . . . . . . . . . . . . . . . . . . . . . . . 5
Tachometer Replacement—Instrument
Cluster Removed
. . . . . . . . . . . . . . . . . . . . . . . . 5
INSTRUMENT CLUSTER REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove 4 instrument panel bezel attaching screws and remove instrument panel bezel. Bezel is snap fit at locations shown (Fig. 2).
Fig. 2 Instrument Bezel Removal/Installation—XJ
(3) Remove cigar lighter housing attaching screws
(Fig. 3).
(4) Remove switch housing attaching screws (if equipped).
(5) Remove instrument panel cluster attaching screws.
(6) Pull out cluster assembly far enough to disconnect 2 multiple plugs and remove instrument cluster.
To install cluster, reverse the removal procedures.
GAUGE REPLACEMENT—INSTRUMENT CLUSTER
REMOVED
(1) Remove cluster lens and gauge bezel (Fig. 4). If equipped with trip odometer, gently pull knob off trip odometer push pin.
(2) Remove gauge attaching screws from rear of mounting bezel. Remove gauge from front.
(3) Install gauge. Install attaching screws.
(4) Install cluster bezel and lens.
(5) Install knob on trip odometer push pin.
Fig. 3 Instrument Cluster Removal/Installation—XJ
SPEEDOMETER REPLACEMENT—INSTRUMENT
CLUSTER REMOVED
(1) Remove cluster lens and gauge bezel.
If equipped with trip odometer, gently pull knob off trip odometer push pin.
(2) Remove 6 mounting screws from cluster housing.
(3) Remove 3 screws from rear of cluster housing
(Fig. 5).
(4) Remove speedometer assembly including circuit board.
(5) Install speedometer with 3 screws.
(6) Install gauge bezel and lens.
(7) Install knob on trip odometer push pin.
TACHOMETER REPLACEMENT—INSTRUMENT
CLUSTER REMOVED
(1) Remove cluster lens and gauge bezel.
If equipped with trip odometer, gently pull knob off trip odometer push pin.
8E - 6 XJ INSTRUMENT PANEL AND GAUGES
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CLUSTER REMOVED
Fig. 4 Instrument Cluster
(2) Remove 3 attaching screws from rear of cluster housing.
(3) Remove tachometer assembly including circuit board.
(4) Install tachometer. Install attaching screws.
(5) Install gauge bezel and lens.
(6) Install knob on trip odometer push pin.
PRINTED CIRCUIT REPLACEMENT—INSTRUMENT
DISASSEMBLY
(1) Remove all attaching screws for gauges, tachometer, and speedometer that are contacting printed circuit (Fig. 5).
(2) Remove screw holding the cluster connector retaining strap to bezel. Remove strap and pivot connector down (Figs. 6 and 7).
(3) Remove lamp sockets from circuit board.
(4) Remove printed circuit including connector.
There is a separate printed circuit for the warning lights that is removed by removing the lamp sockets.
ASSEMBLY
(1) Position printed circuit, including connector, on the back of the instrument panel cluster.
(2) Remove gauge bezel and lens.
(3) Hold components in place and install screws.
(4) Install lamp sockets.
(5) Pivot connector up and install retaining strap.
(6) Install gauge bezel and cluster lens.
GEAR SELECTOR INDICATOR
REPLACEMENT—INSTRUMENT CLUSTER
REMOVED
(1) Remove screws from rear of mounting bezel holding fuel gauge in place.
(2) Remove 2 screws holding gear selector indicator (Fig. 8).
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XJ INSTRUMENT PANEL AND GAUGES 8E - 7
Fig. 5 Printed Circuit Removal/Installation
Fig. 6 Cluster Connector Retaining Strap
(3) Pull cable and clip through hole in the mounting bezel and remove indicator.
(4) Install indicator and cluster.
(5) To adjust indicator, place transmission in PARK.
Fig. 7 Printed Circuit And Cluster Connector
(6) Align pointer on indicator with PARK position.
(7) Install clip to steering column shroud.
(8) Move transmission shift lever to check proper alignment.
8E - 8 XJ INSTRUMENT PANEL AND GAUGES
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Fig. 8 Gear Selector Indicator
INSTRUMENT PANEL REPLACEMENT (Fig. 9)
(1) Disconnect negative cable from battery.
(2) Remove:
•
Parking brake release handle
• lower heat/AC duct below steering column
• ash receiver
Fig. 10 Lower Instrument Panel Removal/Installation
• lower instrument panel (Fig. 10)
• cluster bezel
• cluster assembly
• clock (if equipped)
• radio and heater control panel
• instrument panel switches
• headlamp switch
Fig. 9 Instrument Panel Exploded View
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• antenna connector
• blower motor resistors
• ground lead
• disconnect glove box light
• defroster cowl panel
Remove driver’s side heat/AC outlet to gain access to left hand defroster cowl panel retaining clip to aid in removal (Fig. 11).
• instrument panel attaching bolts
• steering column attaching bolts
• instrument panel assembly
The instrument panel wiring harness is attached to the back of the instrument panel assembly and must be installed correctly for installation.
(3) To install instrument panel, position instrument panel assembly on side mounting bolts (Fig.
12).
(4) Route wiring harnesses and secure instrument panel assembly mounting points.
(5) Connect tube to lap cooler.
(6) Reverse the removal procedures to finish instrument panel installation.
XJ INSTRUMENT PANEL AND GAUGES 8E - 9
Fig. 11 Driver’s Side Defroster Cowl Retaining Clip
Fig. 12 Instrument Panel Installation
8E - 10 XJ INSTRUMENT PANEL AND GAUGES
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XJ INSTRUMENT PANEL AND GAUGES 8E - 11
LOW LINE CLUSTER
8E - 12 XJ INSTRUMENT PANEL AND GAUGES
HIGH LINE CLUSTER
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XJ INSTRUMENT PANEL AND GAUGES 8E - 13
SPECIFICATIONS
INSTRUMENT CLUSTER GAUGES
8E - 14 YJ INSTRUMENT PANEL AND GAUGES
INSTRUMENT PANEL AND GAUGES—YJE
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CONTENTS page
GAUGE PACKAGE DIAGNOSIS
. . . . . . . . . . . . 22
GAUGE PACKAGE GENERAL INFORMATION
. 22
GAUGE PACKAGE SERVICE PROCEDURES
. . 24
INSTRUMENT CLUSTER DIAGNOSIS
. . . . . . . 14
page
INSTRUMENT CLUSTER GENERAL INFORMATION
. 14
INSTRUMENT CLUSTER SERVICE PROCEDURES
. . 17
SPECIFICATIONS
. . . . . . . . . . . . . . . . . . . . . . . 27
INSTRUMENT CLUSTER GENERAL INFORMATION
SPEEDOMETER/ODOMETER SYSTEM
The speedometer/odometer system consists of an electric speedometer and pushbutton reset odometer mounted in the cluster. The system also includes the wire harness from the cluster to the vehicle speed sensor at the transmission, and the adapter and pinion in the transmission. A signal is sent from a transmission mounted vehicle speed sensor to the speedometer/odometer circuitry through the wiring harness. Refer to Group 21 - Transmission for selecting the proper pinion, and selecting and indexing the proper adapter.
TACHOMETER
The tachometer displays the engine speed (RPM).
With the engine running, the tachometer receives an engine speed signal from the Powertrain Control
Module pin 43 (values shown in Specifications chart).
INDICATOR LAMPS
The Brake, Upshift (2.5L with 5 speed transmission except California), and Malfunction Indicator
(Check Engine) lamps are located in the indicator lamp panel above the steering column. The lamps share a common battery feed connection through the ignition switch and fuse #9.
The turn signals, high beam indicator, seat belt reminder, hazard lamp, master lighting and illumination bulbs are supplied battery voltage through various switches and share a common ground.
INSTRUMENT CLUSTER DIAGNOSIS
INDEX
page
Brake Indicator Lamp . . . . . . . . . . . . . . . . . . . . . . 16
Diagnosing—All Lamps Out . . . . . . . . . . . . . . . . . 16
Instrument Panel Illumination Lamps . . . . . . . . . . 16
Malfunction Indicator Lamp (Check Engine) . . . . . 16 page
Seat Belt Reminder Lamp . . . . . . . . . . . . . . . . . . . 16
Speedometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Upshift Indicator Lamp . . . . . . . . . . . . . . . . . . . . . 16
SPEEDOMETER
(1) Raise vehicle.
(2) Disconnect the vehicle speed sensor connector.
(3) Connect a voltmeter between the black wire pin of the connector and ground.
(4) Turn the ignition switch to the ON position.
(5) Check for approximately 5 volts. If OK, perform vehicle speed sensor test. Refer to the appropriate Powertrain Diagnostic Procedures manual. If not
OK, continue with step 6.
(6) Turn ignition switch to OFF position.
(7) Check continuity between vehicle speed sensor connector and terminal 13 of instrument cluster connector. If OK, replace speedometer. If not OK, repair open circuit.
TACHOMETER
(1) Tachometer input is from the Powertrain Control Module (PCM) pin 43. Use the DRB scan tool to perform actuator test. If OK, continue with step 2. If not, replace PCM.
(2) Check for continuity between cluster connector pin 12 and PCM pin 43. If OK, replace tachometer. If not, repair open circuit.
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YJ INSTRUMENT PANEL AND GAUGES 8E - 15
INSTRUMENT CLUSTER
8E - 16 YJ INSTRUMENT PANEL AND GAUGES
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DIAGNOSING—ALL LAMPS OUT
(1) Inspect fuse #9. Replace as required.
(2) Measure voltage at instrument cluster connector terminal 20. Meter should read zero ohms. If not, repair open to ground.
UPSHIFT INDICATOR LAMP
Vehicles equipped with manual transmissions have an optional upshift indicator lamp. The lamp is controlled by the PCM. The lamp lights to indicate when the driver should shift to the next highest gear for best fuel economy. The PCM will turn the lamp off after 3 to
5 seconds if the upshift is not performed. The lamp will remain off until the vehicle stops accelerating and is brought back to the range of lamp operation or shifted into another gear.
The indicator lamp is normally illuminated when the ignition switch is turned ON and it is turned off when the engine is started. The lamp will be lighted during engine operation according to engine speed and load.
(1) Turn ignition switch to ON.
(2) Ground pin 2 of cluster connector. Lamp should light. If not, replace bulb. If OK, continue with step 3.
(3) Turn ignition switch to OFF. Check for continuity between cluster connector pin 2 and pin 54 of the PCM. If not, repair open. If OK, refer to DRB scan tool actuator test of upshift indicator.
BRAKE INDICATOR LAMP
The brake indicator is a dual function lamp. It will indicate an unequal pressure condition in the split brake hydraulic system and it also will indicate when the parking brake is engaged. Separate switches are used for each indicator lamp function. A switch mounted on the brake pedal assembly will close a ground circuit whenever the parking brakes are applied. A second switch is installed in the brake hydraulic lines near the master cylinder. If the switch is balanced by equal pressure on both ends of the switch valve, the valve remains centered and the lamp remains off. If the valve is shifted by unequal pressure between the front or rear brake hydraulic systems, the lamp circuit is connected to ground. To make sure the brake lamp is functional before the vehicle is driven, it is illuminated through a ground circuit when the ignition switch is turned to the START position.
(1) Turn ignition switch to ON.
(2) Ground pin 1 of the cluster connector. Lamp should light. If not, replace bulb. If OK, continue with step 3.
(3) Turn ignition switch to OFF. Check for continuity to park brake switch and brake warning switch.
MALFUNCTION INDICATOR LAMP (CHECK ENGINE)
The Malfunction Indicator Lamp (Check Engine) illuminates each time the ignition switch is turned
ON and stays on for 3 seconds as a bulb test.
If the PCM receives an incorrect signal or no signal from certain sensors or emission related systems the lamp is turned on (pin 32 of PCM). This is a warning that the PCM has recorded a system or sensor malfunction. In some cases when a diagnostic fault is declared the PCM will go into a limp-in mode in an attempt to keep the system operating. It signals an immediate need for service.
The lamp also can be used to display diagnostic trouble codes (DTC). Cycle the ignition switch ON,
OFF, ON, OFF, ON within 5 seconds. This will allow any DTC’s stored in the PCM memory to be displayed in a series of flashes representing digits.
(1) Turn ignition switch to ON.
(2) Ground pin 4 of cluster connector. Lamp should light. If not, replace bulb. If OK, continue with step 3.
(3) Turn ignition switch to OFF. Check for continuity between cluster connector pin 4 and PCM cavity 32. If OK, replace PCM. If not, repair open.
SEAT BELT REMINDER LAMP
Apply 12 volts to terminal 16 of cluster connector.
Lamp should light. If not, replace bulb. If OK, check wiring for an open to buzzer module. Refer to Group
8U - Chime/Buzzer Warning Systems.
INSTRUMENT PANEL ILLUMINATION LAMPS
The instrument panel illumination lamps share two common connections. There is a splice after fuse
#10 that connects the lamps to battery feed. There is also a splice that connects all lamps to ground. Because they share these common connection points in a parallel circuit, the illumination lamps will all come on at the same time. It also means one or more lamps can be out without affecting the operation of the other lamps.
On the battery side of the circuit, the headlamp switch illumination rheostat/switch and panel lamps fuse receive battery feed in series from the park/tail fuse. In the park lamp position, the headlamp switch completes the circuit from the park/tail fuse to the illumination rheostat/switch and panel lamps fuse.
The illumination rheostat contains a variable resistor that allows the driver to vary illumination intensity from off to full brightness.
DIAGNOSIS
(1) Turn parking lamps ON.
(2) Check fuse #10. Replace as required.
(3) Measure voltage at battery side of fuse #10 with rheostat turned counterclockwise to clockwise
(LO to HI). Meter should read zero volts to battery voltage. If not, replace headlamp switch.
(4) Measure resistance at ground side of fuse #10 with parking lamps OFF. Meter should read almost zero ohms (except bulb filament). If not, repair open to ground. If zero ohms, 12 volt supply wire from fuse is shorted to ground, repair short.
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YJ INSTRUMENT PANEL AND GAUGES 8E - 17
INSTRUMENT CLUSTER SERVICE PROCEDURES
INDEX
page
Headlamp Switch/Illumination Rheostat . . . . . . . . 21
Indicator Bezel Replacement . . . . . . . . . . . . . . . . 17
Instrument Cluster Bulb Replacement . . . . . . . . . 19
Instrument Cluster Replacement . . . . . . . . . . . . . 17 page
Printed Circuit Replacement . . . . . . . . . . . . . . . . 19
Rear Defogger/Fog Lamp/Rear Wiper Switches . . 21
Speedometer Replacement . . . . . . . . . . . . . . . . . 17
Tachometer Replacement . . . . . . . . . . . . . . . . . . 17
INSTRUMENT CLUSTER REPLACEMENT
(1) Remove 6 shroud screws (Fig. 1).
Fig. 1 Instrument Shroud Removal/Installation
(2) Slide shroud toward steering wheel.
(3) Remove 3 screws holding right side switch panel (Fig. 2).
(4) Remove 3 screws holding left side switch bezel.
Fig. 2 Cluster Removal
(5) Remove 2 screws holding cluster in place.
(6) Lift up top of cluster. Roll cluster out between steering column and instrument panel far enough to reach connector located behind tachometer.
(7) Disconnect cluster connector and remove cluster (Fig. 3).
(8) To install cluster, reverse the removal procedures.
TACHOMETER REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove instrumentation shroud (Fig. 1). Refer to Instrument Cluster Replacement.
(3) Remove cluster as described in Instrument
Cluster replacement.
(4) Remove 3 screws and tachometer lens (Fig. 4).
(5) Gently pry up clip to release lens from bezel
(Fig. 5).
(6) Remove 3 screws from rear of housing (Fig. 6).
Remove tachometer.
(7) Install tachometer with 3 screws.
(8) Snap lens into place.
(9) Install lens with 3 screws.
(10) To install the cluster, reverse the removal procedures.
SPEEDOMETER REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove instrument shroud (Fig. 1). Refer to Instrument Cluster Replacement.
(3) Remove cluster as described in Instrument
Cluster Replacement.
(4) Remove 3 screws and speedometer lens (Fig. 7).
(5) Gently pry up clip to release lens from bezel
(Fig. 5).
(6) Remove 3 screws from rear of housing (Fig. 8).
Remove speedometer.
(7) Install speedometer with 3 screws.
(8) Snap lens into place.
(9) Install lens with 3 screws.
(10) To install the cluster, reverse the removal procedures.
INDICATOR BEZEL REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove instrumentation shroud (Fig. 1).
(3) Remove 3 screws and tachometer lens (Fig. 4).
8E - 18 YJ INSTRUMENT PANEL AND GAUGES
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Fig. 3 Instrument Cluster
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YJ INSTRUMENT PANEL AND GAUGES 8E - 19
Fig. 4 Tachometer Lens
Fig. 6 Tachometer Removal/Installation
Fig. 5 Cluster Lens Retaining Clip
(4) Gently pry up clip to release lens from bezel
(Fig. 5).
(5) Remove 3 screws and speedometer lens (Fig. 7).
(6) Gently pry up clip to release lens from bezel
(Fig. 5).
(7) Remove indicator bezel (Fig. 3).
(8) Lift indicator panel off locating pins.
(9) Reverse removal procedures to install new panel and bezel.
(10) Install speedometer and tachometer lenses.
(11) Install shroud.
Fig. 7 Speedometer Lens
(12) Install negative cable to battery.
INSTRUMENT CLUSTER BULB REPLACEMENT
Refer to Printed Circuit Replacement for bulb replacement.
PRINTED CIRCUIT REPLACEMENT
Remove cluster as described in cluster replacement.
DISASSEMBLY
(1) Remove all attaching screws for speedometer and tachometer (Fig. 9).
8E - 20 YJ INSTRUMENT PANEL AND GAUGES
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Fig. 8 Speedometer Removal/Installation Fig. 10 Printed Circuit Connector Attaching Screws
Fig. 9 Printed Circuit Removal/Installation
(2) Remove 2 screws holding cluster connector retaining plate to housing (Fig. 10).
(3) To remove plate, slide it toward bottom of housing (Fig. 11).
(4) Remove lamp sockets from circuit board.
(5) Remove printed circuit including connector.
ASSEMBLY
(1) Position printed circuit, including connector, on the back of instrument panel cluster.
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YJ INSTRUMENT PANEL AND GAUGES 8E - 21
Fig. 12 Left Hand Instrument Panel Switch Bezel.
Fig. 11 Cluster Connector Retaining Strap
(2) Remove gauge bezel and lens.
(3) Hold components in place and install screws.
(4) Install lamp sockets.
(5) Pivot connector up and install retaining plate.
(6) Install gauge bezel and cluster lens.
HEADLAMP SWITCH/ILLUMINATION RHEOSTAT
(1) Disconnect negative cable from battery.
(2) Remove instrument cluster shroud (Fig. 1).
(3) Remove 3 screws holding switch bezel (Fig. 12).
(4) Remove 2 screws from the appropriate switch to be replaced (Fig. 13).
(5) Remove the switch connector.
(6) Reverse the removal procedures for installation.
REAR DEFOGGER/FOG LAMP/REAR WIPER
SWITCHES
(1) Disconnect negative cable from battery.
(2) Remove instrument cluster shroud (Fig. 1).
(3) Remove 3 screws holding switch bezel (Fig. 14).
(4) Remove the switch connector.
(5) Release tabs holding switch and remove switch.
(6) Reverse the removal procedures for installation.
Fig. 13 Headlamp Switch/Illumination Rheostat
Fig. 14 Right Hand Instrument Panel Switch Bezel
8E - 22 YJ INSTRUMENT PANEL AND GAUGES
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GAUGE PACKAGE GENERAL INFORMATION
The gauge package contains 4 gauges and the 4 wheel drive indicator. The gauges have a common battery feed from fuse #9 and ignition switch. Although they have separate power sources, the 4 gauges share a common ground connection.
The voltmeter indicates electrical system voltage.
When the engine is not running, the voltage registered is from the battery. After the engine is started, charging system voltage is indicated. In the gauge package, the voltmeter forms a parallel connection across the battery feed and ground.
The remaining gauges - oil pressure, fuel and coolant temperature - are connected to individual sender units. Variable resistors in the senders will change the amount of current allowed to flow through the gauge coils. As current flow through the coils varies, the position of the indicator needle also will vary.
The 4 gauges are connected to battery feed, ground and the sender units through a printed circuit mounted on the back of the gauge housing.
GAUGE PACKAGE DIAGNOSIS
ALL GAUGES INOPERATIVE (Fig. 15)
(1) Check the fuse #9. Replace as required.
(2) Turn ignition switch to ON and measure voltage at battery side of fuse #9. Meter should read battery voltage. If not, repair open from ignition switch.
(3) Unplug gauge package connector from gauge package.
(4) Turn ignition switch to OFF and measure resistance from instrument cluster connector terminals 1 and 13 to a clean chassis ground. Meter should read zero ohms. If not, repair open to ground.
(5) Turn ignition switch to ON and measure voltage at instrument cluster connector terminals 2 and
12. Meter should read battery voltage. If not, repair open from fuse panel.
ONE GAUGE INOPERATIVE
Does not apply to voltmeter.
FUEL GAUGE SENDER
(1) Turn ignition switch to ON.
(2) Separate fuel gauge sender connector from fuel gauge sender near tank.
(3) Ground the center wire of the body harness side of the connector. The gauge should read at low end of scale. If OK, check sending unit (step 4). If not, check circuit between connector and gauge. Repair as required. If circuit is OK, replace gauge.
(4) Turn ignition switch to OFF.
(5) Measure resistance from fuel gauge sender connector center terminal to a clean chassis ground.
Meter readings should correspond to those shown in
Specifications. If not OK, replace sender. If OK, repair open from fuel gauge sender connector to ground.
OIL PRESSURE SENDER
(1) Turn ignition switch to ON.
(2) Unplug oil pressure sender connector from oil pressure sender.
(3) Touch connector to engine block (ground).
Gauge should read at low end of scale.
(4) When connector is NOT touching ground (open circuit) gauge should read at high end of scale. If OK replace sender. If not, proceed with step 5.
(5) Check circuit between sender and gauge for an open. Repair as required. If wiring is OK, replace gauge.
PRINTED CIRCUIT
(1) Turn ignition switch to ON.
(2) Unplug gauge package connector from gauge package.
(3) Measure resistance from gauge package terminal 12 (fuel and coolant temperature gauge) or from terminal 2 (voltmeter and oil pressure gauge) to gauge battery terminal. Meter should read zero ohms. If not, replace/repair printed circuit.
(4) Measure resistance from gauge package terminal 13 (fuel and coolant temperature gauge) or from terminal 1 (voltmeter and oil pressure gauge) to gauge ground terminal. Meter should read zero ohms. If not, replace/repair printed circuit. If zero ohms, replace gauge.
COOLANT TEMPERATURE SENDER
(1) Turn ignition switch to ON.
(2) Unplug coolant temperature sender connector from coolant temperature sender.
(3) Touch connector to engine block (ground).
Gauge should read at high end of scale.
(4) When connector is NOT touching ground (open circuit) gauge should read at low end of scale. If OK replace sender. If not, proceed with step 5.
(5) Check circuit between sender and gauge for an open. Repair as required. If wiring is OK, replace gauge.
GAUGE CALIBRATION VALUES
Use the charts in Specifications. The calibration of the gauge can be checked. If the indicator needle is not in the correct position, replace the gauge.
4WD INDICATOR
The four-wheel drive indicator lamp circuit is completed by the Command-Trac switch located below the battery.
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YJ INSTRUMENT PANEL AND GAUGES 8E - 23
Fig. 15 Gauge Package Wiring Schematic—YJ
8E - 24 YJ INSTRUMENT PANEL AND GAUGES
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GAUGE PACKAGE SERVICE PROCEDURES
PRINTED CIRCUIT REMOVAL
DISASSEMBLY
(1) Remove all gauge attaching screws (Fig. 16).
(2) Remove screw holding the cluster connector retaining plate to the housing (Fig. 16).
(3) To remove the plate, slide it toward the bottom of the housing (Fig. 17).
ASSEMBLY
(1) Position the printed circuit, including connector, on the back of the instrument panel cluster.
(2) Remove gauge bezel and lens.
(3) Hold the components in place and install the screws.
(4) Install the lamp sockets.
(5) Pivot connector up and install retaining plate.
(6) Install gauge bezel and cluster lens.
GAUGE CLUSTER REPLACEMENT
(1) Remove 6 bezel screws (Fig. 18).
Fig. 17 Cluster Connector Retaining Plate
(4) Remove the lamp sockets from the circuit board.
(5) Remove the printed circuit including the connector.
Fig. 18 Gauge Cluster Bezel Removal/Installation
(2) Remove 6 gauge housing mounting screws (Fig.
19).
(3) Unplug the connector from cluster.
(4) To install, reverse the removal procedure.
GAUGE PACKAGE GAUGE REPLACEMENT
This procedure is to be performed with the gauge cluster removed.
Fig. 16 Gauge Package Printed Circuit Removal/Installation
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YJ INSTRUMENT PANEL AND GAUGES 8E - 25
Fig. 19 Gauge Cluster Exploded View
(1) Remove 2 screws from lens.
(2) Remove lens by tilting off of lower hooks (Fig.
20).
(3) Remove bezel.
(4) Remove screws holding appropriate gauge.
(5) To install, insert gauge into housing.
(6) Install screws as required.
(7) Install bezel.
(8) Install lens.
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Fig. 20 Gauge Package Lens Removal
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YJ INSTRUMENT PANEL AND GAUGES 8E - 27
SPECIFICATIONS
INSTRUMENT PANEL GAUGES
INSTRUMENT CLUSTER GAUGES
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AUDIO SYSTEMS 8F - 1
AUDIO SYSTEMS
CONTENTS page
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1
RADIO ANTENNA
. . . . . . . . . . . . . . . . . . . . . . . . 8
page
XJ SERVICE PROCEDURES
. . . . . . . . . . . . . . . . 4
YJ SERVICE PROCEDURES
. . . . . . . . . . . . . . . . 6
DESCRIPTION
GENERAL INFORMATION
Each radio receives ignition feed from an ignition switch controlled fuse. There is an additional in-line fuse in the back of the radio chassis. The in-line fuse will blow in the event an internal short occurs.
The electronically tuned radio (ETR)/cassette models protect the vehicle from a radio failure with an in-line fuse located in the rear of the radio chassis (Fig. 1).
display input of the radio through the relay contacts.
The radio panel illumination is dimmed for night driving.
The ETR models require an additional battery feed connection to the (10 amp #F16 fuse-YJ), (10 amp
#9 fuse-XJ) to retain the radio’s memory when the ignition switch is turned OFF.
ETR models are self-compensating. A radio trimmer adjustment is not required.
DIAGNOSIS
RADIO INOPERATIVE
Turn ignition switch to ON
• Inspect the (#7-YJ), (#2-XJ) fuse and replace if necessary.
•
Measure voltage at battery side of the fuse. There should be 12 volts. If not, repair open from ignition switch.
•
Inspect in-line fuse at rear of radio and replace if necessary.
Turn ignition switch to OFF.
• Disconnect radio connector. Measure resistance from radio ground pin to a clean chassis ground.
There should be zero ohms. If not, repair open between radio connector and ground.
Fig. 1 In-Line Fuse Location
XJ/YJ vehicles are equipped with an Ignition-Off
Draw (IOD) fuse that is removed when the vehicles are shipped from the factory. This fuse is in the
Power Distribution Center to prevent battery discharge during storage. For specific location refer to
Group 8W - Wiring Diagrams.
The IOD fuse is in the radio memory circuitry and should be checked if the memory (time or radio station programming) is inoperative.
All radios are connected to the radio illumination relay. When the ignition switch is in ON or ACCES-
SORY and the radio illumination relay remains deenergized, the radio receives battery voltage via the relay from the:
• (20 amp #7 fuse YJ)
•
(15 amp #2 fuse XJ).
The radio illumination relay is energized when the headlamp switch is used to turn on the parklamps or headlamps. Battery voltage is switched to the dim
NO AUDIO OUTPUT ON ONE OR MORE
SPEAKERS
Refer to Radio Connector Pins.
FRONT SPEAKERS
•
Radio OFF, radio connector disconnected. Measure resistance between radio left front feed and return connector pins. Measure between right front feed and return connector pins. The meter should read 5 to 8 ohms. If the meter reading is correct, remove radio for service. If not, repair wiring or replace speakers as required.
8F - 2 AUDIO SYSTEMS
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REAR SPEAKERS
• Radio OFF, radio connector disconnected. Measure resistance between radio left rear feed and return connector pins. Measure between right rear feed and return connector pins. The meter should read 5 to 8 ohms. If meter reading is correct remove radio for service. If not, repair wiring or replace speakers as required.
DISTORTED AUDIO OUTPUT ON ONE OR
MORE SPEAKERS
•
With the radio ON, substitute known good speaker or speakers. If the sound is still distorted, remove radio for service.
RADIO NOISE DIAGNOSIS
WEAK OR NO RECEPTION; NO AUDIO
OUTPUT; BACKGROUND NOISE PRESENT
Ignition switch in ON, radio ON.
• Inspect antenna cable and connector at radio and tighten or repair as necessary.
• Unplug coax cable and connectors from radio. Measure resistance from center conductor to coaxial shield. The meter should read infinite resistance
(open). If it does not, replace antenna assembly.
• Measure resistance of antenna mast to tip of center conductor at radio end of cable. The meter should read 0 to 0.5 ohms. If it does not, replace lead-in cable or antenna assembly.
• Measure resistance from coaxial shield to chassis ground (vehicle body). The meter should read zero ohms. If it does not, ground antenna base to vehicle body, or replace antenna assembly as required
For all problems with no or low audio output not resolved by these tests, remove radio for service.
MEMORY DOES NOT OPERATE
•
Inspect (F16 in Power Distribution Center-YJ),
(#9 in Fuse Panel-XJ) fuse and replace if necessary.
• Measure voltage at battery side of previously referenced fuse. There should be 12 volts at battery side of fuse. If not, check the Maxi fuse.
Refer to Group 8W - Wiring Diagrams.
• Measure voltage at radio connector pin 4. There should be 12 volts. If meter reading is correct, remove radio for service. If not, repair open from fuse.
RADIO DISPLAY ILLUMINATION (PARKLAMPS
AND HEADLAMPS OPERATING NORMALLY)
Headlamp switch OFF, radio ON.
• Measure voltage at radio connector pin 10. There should be 12 volts. If not, go to next step. If OK, remove radio for repair by authorized outlet.
• Measure voltage at illumination relay pin 3. There should be 12 volts. If 12 volts present, replace illumination relay. If not, repair open in circuit.
RADIO DISPLAY ILLUMINATION DIMMING CIRCUIT
Turn headlamp switch to PARKLAMPS for voltage tests; turn headlamp switch to OFF for resistance tests.
• Separate relay connector from radio illumination relay. Measure resistance from relay connector pin 2 to a clean chassis ground. The meter should read zero ohms. If not, repair open between relay connector and ground.
• Measure voltage at radio illumination relay pin 5.
There should be battery voltage. If not repair open from headlamp switch.
• Measure voltage at radio illumination relay pin 4.
Voltage should vary with dimmer switch. If OK, go to next step. If not, repair open circuit between pin 4 and interior lamp rheostat.
• Measure voltage at radio illumination relay pin
10. Voltage should vary with dimmer switch. If OK, remove radio for repair by authorized outlet. If not, replace radio illumination relay.
NOISE INTERFERENCE CHANGES WITH
ENGINE SPEED
• Inspect connections at: generator, ignition module, antenna coaxial ground, radio ground, body to engine block ground (braided ground strap). Repair as required.
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• Inspect secondary ignition system components: wire routing and condition, distributor cap and rotor, ignition coil, spark plugs. Reroute or replace as required.
RADIO CONNECTOR PINS
AUDIO SYSTEMS 8F - 3
RADIO ILLUMINATION RELAY
XJ
The radio illumination relay is in the relay center.
The relay center is located on the lower instrument panel trim cover, right of the steering column
(Fig. 2).
Fig. 2 Radio Illumination Relay
YJ
The radio illumination relay is taped to the harness above the radio.
8F - 4 AUDIO SYSTEMS
XJ SERVICE PROCEDURES
RADIO REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove instrument panel bezel attaching screws (Fig. 1) and remove the bezel.
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Fig. 3 Disconnect/Connect Radio Wiring Harnesses
Fig. 1 Instrument Bezel Removal/Installation
(3) Remove radio attaching screws (Fig. 2).
Fig. 4 Install Clip In Underside of Dash
RADIO SPEAKERS
INSTRUMENT PANEL MOUNTED SPEAKERS
(1) Remove park brake retaining screw from lower instrument panel (Fig. 5).
Fig. 2 Remove/Install Radio Mounting Screws
(4) Disconnect radio electrical connector, ground lead and antenna lead (Fig. 3).
(5) To install radio, route harness above and to the right of the radio cavity. Install the radio making sure that clip on top of radio (Fig. 4) is installed in mating slot of dash.
(6) Reverse removal procedures to finish installing the radio.
Fig. 5 Park Brake Release Handle
(2) Remove retaining screws and the lower instrument panel (Fig. 6).
(3) Unplug wire harness connector.
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AUDIO SYSTEMS 8F - 5
Fig. 6 Lower Instrument Panel Removal/Installation
(4) Remove speaker screws and speaker from lower instrument panel (Fig. 7).
Fig. 8 Power Window Control Panel Removal/
Installation
Fig. 7 Tweeter Speaker Removal/Installation
(5) To install speaker, reverse the removal procedures.
FRONT DOOR-MOUNTED RADIO SPEAKERS
(1) Remove interior door latch release assembly and control panel retaining screws (Fig. 8).
(2) Disconnect control linkage and wire harness connector.
(3) Remove latch release and control panel assembly.
(4) Remove armrest lower retaining screws.
(5) Swing armrest downward to a vertical position.
This is necessary to disconnect armrest from upper retainer clip (Fig. 9).
(6) Pull armrest straight out from trim panel.
(7) Remove trim panel with a wide flat blade tool
(Fig. 10).
To aid in removal of trim panel, start at the bottom of the panel.
(8) Remove speaker attaching screws and disconnect speaker at wire harness.
Fig. 9 Armrest Retainer Clip
(9) To install a speaker, connect the speaker wire harness and reverse the removal procedure.
REAR LIFTGATE-MOUNTED RADIO SPEAKER
REMOVAL
(1) Remove 2 screws at top outside edges of liftgate trim panel.
(2) Remove trim panel with a wide flat blade tool
(Fig. 11).
To aid in removal of trim panel, start at the bottom of the panel.
(3) Remove speaker attaching screws (Fig. 12).
(4) Disconnect speaker at wiring harness and remove speaker.
8F - 6 AUDIO SYSTEMS
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Fig. 10 Trim Panel Removal
Fig. 11 Liftgate Trim Panel Removal
Fig. 12 Liftgate Speaker
INSTALLATION
(1) Connect speaker at wiring harness.
(2) Install speaker.
(3) Install trim panel by pushing in the plastic trees.
(4) Install door panel screws.
YJ SERVICE PROCEDURES
RADIO REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove gauge cluster panel bezel attaching screws (Fig. 1).
(8) To install radio, reverse the removal procedures.
RADIO SPEAKERS
PASSENGER SIDE
The speaker is located behind grille panel at right end of the instrument panel.
(1) Reach up behind instrument panel and remove
4 stamped nuts holding the speaker in place.
(2) Disconnect speaker electrical connector and remove speaker.
Fig. 1 Gauge Cluster Bezel Removal/Installation
(3) Remove radio bezel.
(4) Remove radio attaching screws.
(5) Disconnect radio antenna cable.
(6) Disconnect radio wire harness.
(7) Remove radio.
DRIVERS SIDE
The speaker is located behind grille panel at left end of the dash panel.
(1) Remove nuts that attach the parking brake pedal assembly mounting studs to the dash panel.
The nuts are accessible from the engine compartment
(Fig. 2).
CAUTION: If vehicle is equipped with a rear window wiper, there is a ground wire attached to top of bolt that attaches the pedal assembly to the instrument panel.
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AUDIO SYSTEMS 8F - 7
Fig. 2 Parking Brake Assembly
(2) Remove bolt that attaches the pedal assembly to the instrument panel and allow pedal assembly to fall out of the way.
(3) Reach up behind instrument panel and remove
4 stamped nuts holding speaker in place.
(4) Disconnect speaker electrical connector and remove speaker.
SOUND BAR—SPEAKER REMOVAL
(1) Pull sound bar padding away from bar on the passenger side (Fig. 3).
(2) Disconnect speaker harness connector located on the passenger side at the sound bar.
(3) Remove screws holding speaker grille and speaker to bar.
(4) Disconnect wires from speaker and remove speaker.
(5) To install speaker, reverse the removal procedures.
SOUND BAR REPLACEMENT
(1) Disconnect speaker harness connector located on the passenger side at the sound bar (Fig. 3)
(2) Remove bolts attaching the sound bar side flanges to the right and left side bars.
(3) Open zipper on sport bar cover.
Fig. 3 Sound Bar Speaker Connector
(4) Remove bolts attaching the sound bar brackets to the sport bar (located on the rear of the sport bar)
(Fig. 4). Slip brackets through the sport bar cover.
Fig. 4 Rear Sound Bar Attaching Bolt
(5) To install the sound bar, reverse the removal procedures.
8F - 8 AUDIO SYSTEMS
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RADIO ANTENNA page
Antenna Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
General Information . . . . . . . . . . . . . . . . . . . . . . . . 8
INDEX
page
Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
GENERAL INFORMATION
AM/FM radio model antennas must have a good ground to eliminate static. The antenna mast is connected to the inner wire of the coaxial cable and is not grounded to any part of the vehicle. The coaxial shield (the wire mesh) surrounding the center conductor wire of the antenna lead-in cable is grounded to the radio and the antenna base.
REPLACEMENT
XJ
(1) Remove the fender inner splash panel mounting nuts (Fig. 1) and move the panel aside to gain access to the antenna base and cable.
The splash panel screws may be covered with undercoating.
Fig. 1 Remove/Install Fender Inner Splash Panel
(2) Remove the antenna mast, nut and antenna pad from the top of the fender (Fig. 2).
(3) Remove the passenger side kick panel.
(4) Disconnect the antenna lead (Fig. 3) by pulling apart while twisting the metal connectors. DO NOT
PULL ON THE COAXIAL CABLE.
(5) Pull the rubber grommet out of the kick panel.
Fig. 2 Remove/Install Nut and Antenna Pad
(6) Remove the antenna assembly from inside the wheel well.
(7) To install the antenna, reverse the removal procedure.
(8) Verify antenna and radio operation.
(9) Apply 3M Rubberized Undercoating, or equivalent to the splash panel screws.
YJ
(1) Remove the radio as described in Radio Replacement.
(2) Remove three screws holding the antenna base and pad to the body (Fig. 4).
(3) Pull the antenna and cable out of the vehicle.
(4) To install the antenna, make sure the antenna pad is placed over the cable and guide the cable under the instrument panel.
(5) Secure the antenna base and pad with three screws.
(6) Install the antenna into the radio and install the radio.
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AUDIO SYSTEMS 8F - 9
Fig. 3 Disconnect Antenna Lead
Fig. 4 Antenna Removal/Install - YJ
ANTENNA TESTS
Antenna ground continuity is checked with an ohmmeter. The following four tests are required (Fig. 5):
• Mast-to-ground test 1.
•
Tip of mast-to-tip of conductor test 2.
• Body ground-to-battery ground test 3.
• Body ground-to-coaxial shield test 4.
Ohmmeter test lead connections are shown in the following schematic.
MAST-TO-GROUND TEST 1.
Test 1 determines if the antenna mast is insulated from the base. Procedure is as follows:
Fig. 5 Antenna Tests
• Connect one ohmmeter lead to tip of antenna mast and the other lead to the antenna base.
• With the antenna disconnected from the radio, there should not be continuity.
TIP OF MAST-TO-TIP OF CONDUCTOR TEST 2.
Test 2 checks the antenna for an open circuit as follows:
•
Disconnect the antenna cable from the radio.
•
Connect one ohmmeter test lead to tip of mast.
Connect remaining lead to tip of antenna cable lead-in (the part inserted into the radio).
• Continuity should exist (ohmmeter should only register a fraction of an ohm). High or infinite resistance suggests damage to the base and cable assembly that should be replaced.
BODY GROUND-TO-BATTERY GROUND TEST 3.
Test 3 checks condition of the vehicle body ground connection as follows:
• Connect one ohmmeter test lead to the vehicle fender and the other lead to the battery negative post.
• Resistance should be less than one ohm.
• If resistance is more than one ohm, check the braided ground strap connected to the engine and vehicle body for being loose, corroded, or damaged. Repair as necessary.
BODY GROUND-TO-COAXIAL SHIELD TEST 4.
Test 4 checks condition of the ground between the antenna base and vehicle body as follows:
• Connect one ohmmeter test lead to the fender and the other lead to the crimp on the coaxial shield.
•
Resistance should be less then one ohm.
•
If resistance is more then one ohm, replace the antenna base attaching screws with new cadmium plated screws.
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HORNS 8G - 1
HORNS
CONTENTS page
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1
HORN SWITCH (HORN PAD) REPLACEMENT . . 3
TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . . . 3
page
XJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
YJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
GENERAL INFORMATION
For XJ/YJ vehicles battery voltage is applied to the horn relay through a fuse.
When the horn switch is depressed, the horn relay is grounded, pulling the contact closed and providing battery voltage to the horns.
A slip ring and brush arrangement in the steering wheel allows the switch circuit to maintain contact while allowing rotation of the steering wheel.
XJ
On XJ models, a cadmium-plated ground screw is used to attach the horn(s) to the body.
Do not substitute other types of ground screws as they may become corroded and cause a loss of ground.
REPLACEMENT
(1) Raise and support the vehicle.
(2) Remove the splash shield.
(3) Remove horn mounting bolt and horn mounted on the drivers side (Fig. 1).
(4) Remove wire from horn.
(5) To install horn, reverse the removal procedures.
DIAGNOSIS AND REPAIR
Refer to Group 8W - Wiring Diagrams for a complete circuit diagram.
HORN RELAY
• Inspect 25 amp, #11 fuse. Replace fuse as required.
• Depress horn switch. The relay contacts should click. If OK, go to HORNS. If not, go to next step.
• Remove the horn relay located in the relay center.
The relay center is on the lower instrument panel trim cover just right of the steering column (Fig. 2).
There should be 12 volts at relay connector pins 1 and 2. If not, repair open in circuit to relay.
•
Depress horn switch. Measure resistance between relay connector pin 5 and ground. The meter should read zero ohms. If not, repair open to horn switch ground.
• Measure resistance between relay connector pin 4 and ground. The meter should read almost zero ohms
(horn resistance) If OK, replace relay. If not, repair open in circuit between relay and horns.
Fig. 1 Drivers Side Horn
8G - 2 HORNS
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HORNS
• Disconnect horn connector. Depress horn switch.
There should be 12 volts at the horn connector. If not, repair open to relay.
• Measure the resistance between the horn bracket and chassis ground. The meter should read zero ohms. If not, check mounting screw for corrosion and replace as necessary.
• If above steps do not identify a problem, replace horns.
Fig. 2 Horn Relay
Wrangler/YJ horns are located on the drivers side inner fender.
YJ
REPLACEMENT
(1) Disconnect wire harness connector from the horn (Fig. 3).
(2) Remove horn and bracket mounting bolt. Horn and bracket are removed as an assembly.
(3) To install, reverse the removal procedures.
DIAGNOSIS AND REPAIR
Refer to Group 8W - Wiring Diagrams for a complete circuit diagram.
HORN RELAY
•
Inspect 10 amp fuse, #F15, located in the power distribution center (PDC). Replace fuse as required.
• Depress horn switch. The relay contacts should click. If OK, go to HORN. If not, go to next step.
• Remove relay from PDC. There should be 12 volts at cavities 2 and 5. If not, repair open in circuit to relay.
• Depress horn switch. Measure resistance between relay cavity 1 and ground. The meter should read zero ohms. If not, repair open to horn switch ground.
• Measure resistance between relay cavity 4 and ground. The meter should read almost zero ohms
(horn resistance) If OK, replace relay. If not, repair open in circuit between relay and horn.
Fig. 3 Horn Removal/Installation—YJ
HORN
• Disconnect horn connector. Depress horn switch.
There should be 12 volts at the horn connector pin A.
If not, repair open to relay.
•
Measure the resistance between the horn connector pin B and chassis ground. The meter should read zero ohms. If not, repair open to ground.
•
If above steps do not identify a problem, replace horn.
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HORN SWITCH (HORN PAD) REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove horn button by pulling straight up.
(3) Remove horn button components (Fig. 4).
(4) To install the switch, reverse the removal procedures.
HORNS 8G - 3
(5) Connect negative cable to battery.
Fig. 4 Steering Wheel Removal/Installation
TORQUE SPECIFICATIONS
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VEHICLE SPEED CONTROL SYSTEM 8H - 1
VEHICLE SPEED CONTROL SYSTEM
CONTENTS page page
SERVICE PROCEDURES
. . . . . . . . . . . . . . . . . . . 9
TEST PROCEDURES
. . . . . . . . . . . . . . . . . . . . . . 5
GENERAL INFORMATION
The vehicle speed control system (Fig. 1) is electrically actuated and vacuum operated. The turn signal lever on the steering column incorporates a slide switch that has three positions OFF, ON or RE-
SUME. A SET button is in the end of the lever. This device is designed to operate at speeds above approximately 35 mph.
WARNING: THE USE OF SPEED CONTROL IS NOT
RECOMMENDED WHEN DRIVING CONDITIONS DO
NOT PERMIT MAINTAINING A CONSTANT SPEED,
SUCH AS HEAVY TRAFFIC OR ON ROADS THAT
ARE WINDING, ICY, SNOW COVERED, OR SLIP-
PERY.
TO ACTIVATE: Put ON/OFF switch in ON position. When the desired speed is achieved, push and release the SET button to turn on and engage the system. Remove foot from accelerator. Speed will be maintained at this level.
TO DEACTIVATE: A soft tap of the brake pedal, normal brake application or depressing the clutch pedal while the system is engaged will disengage speed control without erasing memory. A sudden increase in engine speed may be experienced if the clutch pedal is depressed while the speed control system is engaged. Moving the slide switch to the OFF position or turning the ignition OFF also disengages the system and in addition erases the memory.
Fig. 1 Speed Control System
8H - 2 VEHICLE SPEED CONTROL SYSTEM
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TO RESUME AFTER BRAKING: After disengaging the speed control system by tapping the brake pedal or clutch pedal, push the RESUME/ACCEL button to return vehicle to the previously set speed.
SET/COAST: Speed can be decreased by holding
SET button against stop until desired speed is attained. Releasing the button engages the system at that speed. A decrease in speed also can be attained by tapping brake pedal lightly disengaging system.
When desired speed has been obtained push and release SET button.
TO ACCELERATE FOR PASSING: Depress accelerator as needed. When passing is completed, release accelerator and vehicle will return to previous speed setting. There may be a slight (3-7 mph) speed loss before the vehicle recovers to the set speed.
TAP-UP: When the speed control system is engaged, tapping the RESUME/ACCEL button will increase the speed setting by 2 mph (3 km/h). The system will respond to multiple tap-ups.
TO ACCELERATE: While speed control is engaged, hold the RESUME/ACCEL button depressed and release at a new desired speed. This will allow the vehicle to accelerate and set at a higher speed setting.
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VEHICLE SPEED CONTROL SYSTEM 8H - 3
8H - 4 VEHICLE SPEED CONTROL SYSTEM
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VEHICLE SPEED CONTROL SYSTEM 8H - 5
TEST PROCEDURES
INDEX
page
Checking for Diagnostic Trouble Code
Electrical Tests at Powertrain Control Module
Electrical Tests at Servo
. . . . . . . . . . . . . . . . . . . . 5
Inoperative System
. . . . . . . . . . . . . . . . . . . . . . . . 5
Operational Check (Road Test)
. . . . . . . . . . . . . . . 7
Road Test
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
page
Speed Control Switch (Turn Signal Lever) Test
Stop Lamp Speed Control Switch Test
Vacuum Supply Test
. . . . . . . . . . . . . . . . . . . . . . . 7
Vehicle Speed Control System Electrical Tests
Vehicle Speed Sensor Test
. . . . . . . . . . . . . . . . . . 5
ROAD TEST
Refer to Operational Check (Road Test) section to verify reports of speed control system malfunction.
INOPERATIVE SYSTEM
Road test vehicle to verify reports of speed control system malfunction. An inspection should be made for loose electrical and vacuum connections at the servo.
Check for correct installation of the vacuum check valve in the hose from servo to vacuum source. The word VAC on the valve must point toward the vacuum source.
Corrosion should be removed from electrical terminals and a light coating of Mopar MultiPurpose
Grease, or equivalent, applied.
Inspection also should be made to verify that both ends of the speed control cable are securely attached.
CHECKING FOR DIAGNOSTIC TROUBLE CODE
(1) When trying to verify a speed control system electronic malfunction use a DRB scan tool to find the cause (refer to Powertrain Diagnostic Procedures manual).
If DRB is not available, the Diagnostic Trouble
Code (DTC) may be determined with the following method:
(a) With key inserted in ignition switch, cycle switch to ON position 3 times. On third cycle, leave switch in ON position.
(b) After switch has been cycled 3 times, observe
Malfunction Indicator Lamp (CHECK ENGINE) on instrument cluster. If a DTC is present, the code will be displayed in a series of flashes representing digits. Three flashes in rapid succession, a slight pause, then 4 flashes in rapid succession would indicate DTC 34.
(2) If a DTC 34 is observed, perform tests in the sections Electrical Tests at Servo and Electrical Tests at Powertrain Control Module.
If a DTC 15 is observed, perform test for a faulty vehicle speed sensor.
(3) Correct any problems found when performing these tests and recheck for DTC if changes were made.
VEHICLE SPEED SENSOR TEST
For testing of the vehicle speed sensor and related components, refer to Powertrain Diagnostic Procedures manual.
VEHICLE SPEED CONTROL SYSTEM ELECTRICAL
TESTS
Vehicle speed control systems may be tested using two different methods. One involves use of a DRB scan tool. If this test method is desired, refer to Powertrain Diagnostic Procedures manual.
The other test method uses a voltmeter. The voltmeter method is described in the following tests.
If any information is needed concerning wiring, refer to Section 8W - Wiring Diagrams.
CAUTION: When test probing for voltage or continuity at electrical connectors, care must be taken not to damage connector, terminals, or seals. If these components are damaged, intermittent or complete system failure may occur.
ELECTRICAL TESTS AT SERVO
(1) Turn ignition switch to the ON position. With speed control switch in the ON position, setup a voltmeter to read battery voltage and connect negative lead to a good chassis ground.
(2) Disconnect 4-way connector going to servo
(Figs. 2 and 3). Blue wire with red tracer of main harness 4-way connector should read approximately battery voltage. If not, check for loose connections, brake switch adjustment or, repair main harness as necessary.
(3) Connect a jumper wire between male and female terminals of blue wire with red tracer. The other 3 male terminals from servo should show battery voltage. If not, replace servo.
(4) Using an ohmmeter, connect one lead to a good body ground. Touch other lead to black wire terminal in 4-way connector of main harness. Meter should show continuity. If not, repair ground circuit as necessary.
8H - 6 VEHICLE SPEED CONTROL SYSTEM
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Fig. 4 Powertrain Control Module and Connector
Location
Fig. 2 Servo And Harness Connector—Left Hand
Drive
Fig. 3 Servo And Harness Connector—Right Hand
Drive
ELECTRICAL TESTS AT POWERTRAIN CONTROL
MODULE
(1) Unplug 60-way connector from Powertrain Control Module, located on drivers side fender (Fig. 4).
(2) Connect negative lead of voltmeter to a good body ground near module.
(3) For the following tests, ignition switch must be in ON position. Refer to Fig. 5 for controller terminal locations. Touch positive lead of voltmeter to terminal in cavity number 33. With speed control switch in OFF position, voltmeter should read 0 volts. With speed control switch in ON position, voltmeter should read battery voltage. If not, repair main harness as necessary.
Fig. 5 Powertrain Control Module 60-Way Connector
Shown from Terminal End
(4) Touch positive lead of the voltmeter to terminal in cavity number 53. As in step (3), voltmeter should read 0 volts with switch in OFF position and battery voltage with switch in ON position.
(5) Touch positive lead of voltmeter to terminal in cavity number 48. With speed control switch in OFF position, voltmeter should read 0 volts. With switch in ON position, voltmeter should read battery voltage. Pressing SET button should cause voltmeter to change from battery voltage to 0 volts for as long as the switch is held. If not, perform the speed control switch test. If the switch is not at fault, then check main harness and repair as necessary.
(6) Touch positive lead of voltmeter to terminal in cavity number 50. The voltmeter should read 0 volts with speed control switch in either OFF or ON position. With switch in either RESUME or SET position, voltmeter should read battery voltage. If not, perform the speed control switch test. If the switch is not at fault, then check main harness and repair as necessary.
(7) Touch positive lead of voltmeter to terminal in cavity number 49. The voltmeter should read 0 volts with switch in OFF position. With switch in ON position, voltmeter should read battery voltage. The voltmeter will continue to read battery voltage when either the SET or RESUME switch is pressed. If not,
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VEHICLE SPEED CONTROL SYSTEM 8H - 7
perform the speed control switch test. If switch is not at fault, then check main harness and repair as necessary.
(8) Using an ohmmeter, connect one lead to a good body ground and touch other lead to terminal in cavity number 29. With brake pedal released, meter should show continuity. When pedal is depressed, meter should show open circuit.
SPEED CONTROL SWITCH (TURN SIGNAL LEVER)
TEST
STOP LAMP SPEED CONTROL SWITCH TEST
(1) Disconnect double connector at switch pigtail and connect a 12 volt source to either terminal. Connect a test lamp between other terminal and a good ground. The test lamp should be on when brake pedal is in normal position. The test light should go off when brake pedal is depressed approximately 3/8 of an inch.
(2) If test lamp does not respond properly, the stop lamp switch is defective or out of adjustment.
(3) Stop lamp switch adjustment is detailed in
Group 5 - Brakes section of this manual.
VACUUM SUPPLY TEST
(1) Disconnect vacuum hose at servo or vacuum reservoir and install a vacuum gauge in hose (Fig.
6).
(2) Start engine and observe gauge at idle. Vacuum gauge should read at least ten inches of mercury.
(3) If vacuum does not meet this requirement, check for vacuum leaks or poor engine performance.
OPERATIONAL CHECK (ROAD TEST)
The following sequential checks are performed with the speed switch ON and vehicle speed faster than 35 mph:
(1) Press the SET button in end of multi-function lever. Vehicle should maintain set speed.
(2) Hold SET button in, and remove foot from accelerator. Vehicle should coast to a slower speed.
(3) Release SET button. Speed control will engage and hold a slower speed, provided the speed remains above 35 mph.
8H - 8 VEHICLE SPEED CONTROL SYSTEM
J
(4) Slide speed switch to RESUME/ACCEL and hold it there. Vehicle should accelerate.
(5) Release speed switch back to ON. Vehicle will hold the new faster speed, if SET speed button has been pressed.
(6) Tap brake pedal. Vehicle will decelerate.
If vehicle has a manual transmission, repeat test, but depress the clutch pedal.
(7) Slide speed switch momentarily RESUME/AC-
CEL. Vehicle will accelerate to former set speed.
(8) While cruising, accelerate, then remove foot from accelerator. Vehicle will coast back to set speed.
(9) While speed control is engaged, tap SET button. Vehicle speed will increase 2 mph for each time
SET button is tapped.
Fig. 6 Vacuum Gauge Test
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VEHICLE SPEED CONTROL SYSTEM 8H - 9
SERVICE PROCEDURES page
Servo Cable Replacement
. . . . . . . . . . . . . . . . . . . 9
Speed Control Servo Replacement
INDEX
page
Speed Control Switch Replacement
SPEED CONTROL SERVO REPLACEMENT
REMOVAL
(1) Disconnect vacuum hose at servo (Figs. 1 and
2).
(2) Disconnect electrical connector at servo.
(3) Remove 2 nuts from cable sleeve.
(4) Pull speed control cable away from servo to expose cable retaining clip.
(5) Remove clip attaching cable to servo.
(6) Pull servo away from mounting bracket.
Fig. 1 Speed Control Servo—Left Hand Drive
INSTALLATION
(1) Insert servo studs through holes in servo mounting bracket.
(2) With throttle blocked to full open position, align hole in cable sleeve with hole in servo pin and install retaining clip.
(3) Insert servo studs through holes in cable sleeve.
(4) Install 2 attaching nuts and tighten to 6 N z m
(50 in. lbs.).
(5) Connect vacuum hose to servo.
(6) Connect electrical connector to servo terminals.
Fig. 2 Speed Control Servo—Right Hand Drive
SERVO CABLE REPLACEMENT
CAUTION: Use finger pressure only to remove the speed control cable connector at the bell crank. Pliers or screwdriver can break connector requiring complete cable replacement.
(1) Using finger pressure only, remove speed control cable connector at bell crank by pushing connector off the bell crank (Fig. 3). DO NOT try to pull connector off perpendicular to the bell crank.
(2) Squeeze tabs on speed control cable and push out of locking plate (Fig. 4).
(3) Pull cable out of cable guide.
(4) Remove 2 nuts and cable housing from servo.
(5) Release cable clip from servo cable and remove servo cable.
(6) To install, reverse the removal procedure.
SPEED CONTROL SWITCH REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove horn button with a push and turn motion.
(3) Remove horn button components (Fig. 5).
(4) Turn ignition switch to LOCK position and remove steering wheel nut and washer.
(5) Scribe an alignment mark on the steering in line with the mark already existing on the end of the steering column.
8H - 10 VEHICLE SPEED CONTROL SYSTEM
J
Fig. 3 Remove Bell Crank Connector
Fig. 4 Remove/Install Speed Control Cable to
Locking Plate
(6) Remove vibration damper from the steering column hub, if equipped.
Fig. 5 Steering Wheel Removal/Installation
(7) Remove steering wheel using a steering wheel puller.
WARNING: TO REMOVE THE STEERING SHAFT
SNAP RING IN THE FOLLOWING STEP, THE LOCK-
PLATE MUST BE COMPRESSED. DO NOT ATTEMPT
TO REMOVE THE LOCKPLATE WITHOUT COM-
PRESSOR TOOL C4156 AS THE LOCKPLATE IS UN-
DER HEAVY SPRING TENSION.
(8) Compress lockplate with compressor tool
C4156.
(9) Remove steering shaft snap ring (Fig. 6). Discard snap ring. It is not reusable.
(10) Remove compressor tool.
(11) Remove lockplate, cancelling cam, and upper bearing preload spring.
(12) Remove horn button components from canceling cam.
(13) Remove screw and hazard warning switch knob.
(14) Remove actuator arm attaching screw.
(15) Remove turn signal switch attaching screws.
(16) Unplug speed control switch connector.
(17) Pull speed control harness out of the column.
(18) Insert ignition key in lock cylinder and turn key to ON position.
(19) Remove key warning buzzer switch and retaining clip with a paper clip inserted below retainer so that retainer is flattened (Fig. 7).
Do not attempt to remove buzzer switch and clip separately. The clip could fall into the column jacket.
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VEHICLE SPEED CONTROL SYSTEM 8H - 11
Fig. 6 Lockplate Removal Fig. 8 Lock Cylinder Removal/Installation
Fig. 7 Buzzer Switch Removal
(20) Remove ignition lock cylinder retaining screw and pull lock cylinder out of column housing (Fig. 8).
(21) Remove screws that attach housing and shroud assembly to column jacket and carefully remove housing and shroud assembly (Fig. 9).
Do not let dimmer switch rod, lock pin or lock rack fall out.
(22) Remove turn signal/wiper lever by pulling it straight out of column.
Fig. 9 Steering Column Housing
Removal/Installation
(23) Remove wiper switch cover from back of housing and shroud assembly (Fig. 10). If equipped with column shift, remove screw holding the cover on.
(24) Remove pivot screw from housing and remove wiper switch.
(25) Install a new switch and switch cover.
(26) Push on dimmer switch rod to make sure it is connected then carefully position housing and shroud assembly to column (Fig. 11).
8H - 12 VEHICLE SPEED CONTROL SYSTEM
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Fig. 10 Remove Pivot Screw
Make sure nylon spring retainer on the lock pin is positioned forward of retaining slot of lock rack (Fig. 11).
Position the first tooth of gear (farthest from the block tooth) with the most forward tooth of lock rack.
(27) Install screws that attach housing and shroud assembly to column jacket and carefully mate housing and shroud assembly.
(28) Insert key and lock cylinder and test that the lock pin extends fully when key is moved to lock position.
Fig. 11 Check Dimmer Switch Rod and Lock Pin
(29) To install remaining parts, reverse the removal procedures.
CAUTION: When installing a wiper switch, make sure wires are laying flat on bottom inside column.
On vehicles equipped with column shift, install PRNDL cable clip with shift indicator on
N. Move selector through the range and make sure it lines up with each letter.
(30) Install steering wheel. Tighten steering wheel nut to 34 N z m (25 ft. lbs.) torque.
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TURN SIGNALS AND HAZARD WARNING FLASHER 8J - 1
TURN SIGNALS AND HAZARD WARNING FLASHER
CONTENTS page
HAZARD LAMPS—XJ
. . . . . . . . . . . . . . . . . . . . 1
HAZARD LAMPS—YJ
. . . . . . . . . . . . . . . . . . . . 2
TURN SIGNALS—XJ
. . . . . . . . . . . . . . . . . . . . . 1
page
TURN SIGNALS—YJ
. . . . . . . . . . . . . . . . . . . . . 2
TURN/HAZARD SWITCH REPLACEMENT - ALL
MODELS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
TURN SIGNALS—XJ
Refer to Section 8W - Wiring Diagrams for circuit wiring diagram.
DESCRIPTION
With the turn signal lever in its up or down position and the ignition switch in ACCESSORY or ON, current flows through the:
• turn/hazard switch
• selected turn indicator bulb
• front and rear turn signal bulbs
• and the front side marker bulb.
With the headlamps OFF, the turn and front side marker lamps flash in unison. With the headlamps
ON, the turn and front side marker lamps flash alternately.
DIAGNOSIS—TURN SIGNAL INOPERATIVE
(1) A turn signal indicator that does not flash usually indicates a burned out turn signal bulb. Check for and replace if defective. System should now function properly. If not, go to next step.
High generator output voltage can burn out lamps rapidly.
(2) Remove and inspect 20 amp #8 fuse. Replace if necessary. If OK, go to next step.
(3) Remove turn flasher, light blue can, located in upper left corner of fuse block.
(4) Turn ignition switch to ACCESSORY. Check for battery voltage at flasher bottom cavity on fuse block. If OK, go to next step. If not, repair open circuit in wiring between turn flasher and #8 fuse.
(5) Turn ignition switch to ACCESSORY. Move turn signal lever up or down. Replace turn flasher with known good flasher. The lamps should flash. If not, replace original flasher and go to next step.
(6) Turn ignition switch to OFF. Follow procedure for turn/hazard switch replacement to locate steering column connector. Unplug connector.
(7) Turn ignition switch to ACCESSORY. Check for battery voltage at connector terminal L. If OK, replace turn/hazard switch and check that lamps flash. If not, repair open circuit in wiring between turn flasher and steering column connector terminal
L.
HAZARD LAMPS—XJ
Refer to Section 8W - Wiring Diagrams for circuit wiring diagram.
DESCRIPTION
With the hazard switch ON, current flows through the:
• hazard flasher
• the turn/hazard switch
• two front turn signal bulbs
• two rear turn signal bulbs
• two front side marker bulbs
• and two turn indicator bulbs.
All of these bulbs will flash on and off.
DIAGNOSIS—HAZARD LAMPS INOPERATIVE
(1) Inspect 20 amp #F13 fuse in Power Distribution Center (PDC). The PDC is located in the engine compartment, passenger side. For location of fuse, check underside of PDC cover. Replace if necessary.
If OK, go to next step.
(2) Remove hazard flasher (tin can) located in fuse block.
(3) Check for battery voltage at the terminal on the right (3 o’clock). If OK, go to next step. If not, repair open circuit in wiring between #F13 fuse and hazard flasher right terminal.
(4) Replace hazard flasher with known good flasher. Activate hazard warning switch. Lamps should flash. If not, replace original flasher and go to next step.
(5) Follow procedure for turn/hazard switch replacement to locate steering column connector. Unplug connector.
(6) Check for battery voltage at connector terminal
K. If OK, replace turn/hazard switch. If not, repair open circuit in wiring between hazard flasher and steering column connector terminal K.
8J - 2 TURN SIGNALS AND HAZARD WARNING FLASHER
J
TURN SIGNALS—YJ
Refer to Section 8W - Wiring Diagrams for circuit wiring diagram.
DESCRIPTION
With the turn signal lever in its up or down position and the ignition switch in ACCESSORY or ON, current flows through the:
• turn/hazard switch
• selected turn indicator bulb
• front and rear turn signal bulbs
• front side marker bulb
With the headlamps OFF, the turn and side marker lamps flash in unison. With the headlamps
ON, the turn and side marker lamps flash alternately.
DIAGNOSING—TURN SIGNAL INOPERATIVE
(1) A turn signal indicator that does not flash usually indicates a burned out turn signal bulb. Check for and replace if defective. System should now function properly. If not, go to next step.
High generator output voltage can burn out lamps rapidly.
(2) Locate fuse block under driver’s side of instrument panel.
(3) Remove and inspect 15 amp #4 fuse. Replace if necessary. If OK, go to next step.
(4) Remove turn flasher, light blue can, located in fuse block.
(5) Turn ignition switch to ACCESSORY. Check for battery voltage at cavity on left (closest to hazard flasher can). If OK, go to next step. If not, repair open circuit in wiring between turn flasher and #4 fuse.
(6) Turn ignition switch to ACCESSORY. Move turn signal lever up or down. Replace turn flasher with known good flasher. The lamps should flash. If not, replace original flasher and go to next step.
(7) Turn ignition switch to OFF. Follow procedure for turn/hazard switch replacement to locate steering column connector. Unplug connector.
(8) Turn ignition switch to ACCESSORY. Check for battery voltage at connector terminal L. If OK, replace turn/hazard switch. If not, repair open circuit in wiring between turn flasher and steering column connector terminal L.
HAZARD LAMPS—YJ
Refer to Section 8W - Wiring Diagrams for circuit wiring diagram.
DESCRIPTION
With the hazard switch ON, current flows through the:
• hazard flasher
• turn/hazard switch
• two front turn signal bulbs
• two rear turn signal bulbs
• two front side marker bulbs
• two turn indicator bulbs.
All of these bulbs will flash on and off.
DIAGNOSIS—HAZARD LAMPS INOPERATIVE
(1) Inspect 20 amp #F5 fuse in Power Distribution
Center (PDC). The PDC is located in the engine compartment, passenger side. For location of fuse, check underside of PDC cover. Replace if necessary. If OK, go to next step.
(2) Remove hazard flasher (tin can) located in fuse block.
(3) Check for battery voltage at the terminal on the left. If OK, go to next step. If not, repair open circuit in wiring between #F5 fuse and hazard flasher left terminal.
(4) Replace hazard flasher with known good flasher. Activate hazard warning switch. Lamps should flash. If not, replace original flasher and go to next step.
(5) Follow procedure for turn/hazard switch replacement to locate steering column connector. Unplug connector.
(6) Check for battery voltage at connector terminal
K. If OK, replace turn/hazard switch. If not, repair open circuit in wiring between hazard flasher and steering column connector terminal K.
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TURN SIGNALS AND HAZARD WARNING FLASHER 8J - 3
TURN/HAZARD SWITCH REPLACEMENT - ALL MODELS
(1) Disconnect negative cable from battery.
(2) Remove the horn button with a push and turn motion.
(3) Remove the horn button components (Fig. 1).
Fig. 1 Steering Wheel Removal/Installation
(4) Turn ignition switch to LOCK position and remove steering wheel nut and washer.
(5) Scribe an alignment mark on the steering in line with the mark already existing on the end of the steering column.
(6) Remove vibration damper from the steering column hub, if equipped.
(7) Remove the steering wheel using a steering wheel puller. DO NOT hammer on puller or end of steering shaft.
WARNING: TO REMOVE THE STEERING SHAFT
SNAP RING IN THE FOLLOWING STEP, THE LOCK-
PLATE MUST BE COMPRESSED. DO NOT AT-
TEMPT TO REMOVE THE LOCKPLATE WITHOUT
COMPRESSOR TOOL C4156 AS THE LOCKPLATE
IS UNDER HEAVY SPRING TENSION.
(8) Compress lockplate with compressor tool
C4156.
(9) Remove steering shaft snap ring (Fig. 2). Discard snap ring. It is not reusable.
(10) Remove compressor tool.
(11) Remove lockplate, cancelling cam, and upper bearing preload spring.
(12) Remove horn button components from canceling cam.
Fig. 2 Lockplate Removal
(13) Remove the screw and hazard warning switch knob.
(14) Remove dimmer switch actuator arm attaching screw (Fig. 3).
Fig. 3 Turn/Hazard Switch And Dimmer Actuating
Arm Screws
(15) Remove turn/hazard switch attaching screws.
(16) XJ—Remove lower instrument panel cover trim panel.
(17) YJ
8J - 4 TURN SIGNALS AND HAZARD WARNING FLASHER
(a) Remove 6 housing screws (Fig. 4).
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Fig. 4 Instrument Housing Removal/Installation—YJ
(b) Slide housing toward steering wheel.
(18) Remove cover under column.
(19) If vehicle is equipped with a column shift, remove PRNDL cable clip (Fig. 5).
Fig. 6 Lower Steering Column
(23) Push turn/hazard connector up and out of steering column connector (Fig. 7).
Fig. 5 PRNDL Cable Clip Removal/Installation
(20) Remove 2 nuts holding steering column bracket to brake sled (Fig. 6).
(21) Remove 4 bolts holding steering column bracket to column.
(22) Loosen column brace mounting nut at drivers side kick panel. This will allow column to drop.
Fig. 7 Turn/Hazard Switch And Steering Column
Connectors
(24) Pry up locking tabs of steering column connector and remove connector from column bracket.
(25) Tape connector to wires as shown (Fig. 8).
(26) Remove plastic harness cover by pulling it up and over the weld nuts then open and slide the cover off the harness (Fig. 9).
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Fig. 8 Tape Wiper Switch Connector
TURN SIGNALS AND HAZARD WARNING FLASHER 8J - 5
(28) To install a new switch, reverse the removal procedure.
CAUTION: When installing a turn/hazard switch, make sure wires are laying flat on bottom inside column.
On vehicles equipped with column shift, install the PRNDL cable clip with the shift indicator on N (neutral). Move the selector through the range and make sure it lines up with each letter.
(29) Adjust the headlamp dimmer switch as described in Group 8L - Lamps.
Fig. 9 Remove Plastic Harness Cover
(27) Remove the turn/hazard switch. Pull the switch and wire harness straight up and out of the housing.
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WINDSHIELD WIPERS
WINDSHIELD WIPERS 8K - 1
CONTENTS page
WIPER CONTROL SWITCH REPLACEMENT
. . 15
WIPER SWITCH TESTING
. . . . . . . . . . . . . . . . 19
page
XJ
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
YJ
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
XJ
INDEX
page
Diagnosing Rear Wiper
. . . . . . . . . . . . . . . . . . . . . 6
Diagnosing Rear Wiper Washer
Diagnosing Windshield Washer (Intermittent)
Diagnosing Windshield Washer (Non-Intermittent)
Diagnosing Windshield Wipers
. . . . . . . . . . . . . . . 11
Front Wipers/Washers
. . . . . . . . . . . . . . . . . . . . . . 1
Intermittent Wiper Module
. . . . . . . . . . . . . . . . . . . 5
Liftgate Wiper
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
page
Liftgate Wiper Switch Replacement
Rear Wiper/Washer Switch Testing
Torque Specifications XJ
. . . . . . . . . . . . . . . . . . . . 7
Washer Pump Replacement
. . . . . . . . . . . . . . . . . 6
Washer Pump Replacement—Left Hand Drive
Washer Pump Replacement—Right Hand Drive
Windshield Wiper Motor
. . . . . . . . . . . . . . . . . . . . 2
FRONT WIPERS/WASHERS
GENERAL
Two-speed electric windshield wipers and electric washers are standard equipment. An optional intermittent wiper system provides a pause between wipe cycles for use during conditions of very light precipitation.
The windshield wipers can be operated with the windshield wiper switch only when the ignition switch is in the ON or ACCESSORY position. A circuit breaker located in the fuse block protects the circuitry of the wiper system.
WIPERS
The standard windshield wiper circuit contains three components; wiper/washer switch, motor, and front washer pump. Both standard and intermittent circuits are the same, except that the intermittent circuit requires a module and delay resistance in the wiper switch. Both circuits receive battery feed from, and are protected by a 5.5 amp circuit breaker.
In the standard wiper circuit, the switch connects the motor directly to battery feed for low and high speed operation. In the intermittent circuit, the switch supplies battery feed to the intermittent wiper module, which then supplies the motor. In the delay position, the module is connected with the variable resistor in the wiper switch. The value of the resistance is used by the module to charge a capacitor, which triggers the amount of delay between wipes.
The wiper motor has an arrangement of brushes providing the two wiper speeds. When the wipers are turned off, the park switch maintains current to the motor until the wipers reach the park position on the windshield.
The park arm in the motor assembly is connected to the park switch and is driven by the motor. When the wiper switch is turned off, current flows through the contact and the module to the motor until the wipers reach the park position.
CAUTION: The wiper arms and blades must not be moved manually from side to side or damage may result.
WASHERS
With the washer switch ON, current flows through the washer pump to ground. The front washer pump runs as long as the driver holds the switch ON. On standard wipers, the washer switch automatically moves the wiper switch to LO when the washer is turned on. On intermittent wipers, the wiper module runs the wiper motor on LO. Turning the switch to
OFF stops the wipers.
If the washer knob is depressed while the wiper switch is in the OFF position, the wiper control will operate for approximately 3 wipes and automatically turn OFF.
8K - 2 WINDSHIELD WIPERS
WINDSHIELD WIPER MOTOR
REMOVAL
(1) Remove wiper arm assemblies by lifting blade off windshield and pulling out on the tab (Fig. 1) to lock wiper arm in UP position.
J
(3) Position cowl mounting bracket and install the attaching nuts. Install pivot pin attaching screws.
Tighten the screws and nuts to 4 N z m (35 in. lbs.) torque.
(4) Connect the wire harness.
(5) Connect the washer hose and install cowl trim panel.
(6) Install the wiper arm assemblies and position as shown (Fig. 3).
Fig. 1 Wiper Arm Removal
(2) Remove cowl trim panel. Disconnect the washer hose. Remove the cowl mounting bracket attaching nuts (Fig. 2) and pivot pin attaching screws.
Fig. 3 Windshield Wiper Arm Installation
WASHER PUMP REPLACEMENT—LEFT HAND
DRIVE
(1) Remove 2 washer reservoir attaching screws
(Fig. 4) and 1 nut (Fig. 5).
Fig. 2 Pivot Assembly Removal
(3) Disconnect wiring harness and remove the assembly.
(4) Remove the plastic motor cover.
(5) Remove bolts and nuts holding motor to linkage and remove motor.
The wiper motor is shrouded in a protective rubber boot. Care should be taken not to puncture the boot during removal or installation.
INSTALLATION
(1) Install motor to linkage.
(2) Install wiper motor and linkage assembly into the cowl cavity.
Fig. 4 Washer Reservoir Upper Attaching Screws
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WINDSHIELD WIPERS 8K - 3
(5) Reverse the removal procedure to install a new pump(s).
WASHER PUMP REPLACEMENT—RIGHT HAND
DRIVE
(1) Remove 3 washer reservoir mounting screws
(Fig. 7).
Fig. 5 Washer Reservoir Lower Attaching Nut
(2) Disconnect hose from pump(s) (Fig. 6).
Fig. 6 Washer Reservoir and Pumps—Typical Left
Hand Drive
(3) Drain washer reservoir.
(4) Using a deep socket, remove filter nut(s) from bottom inside reservoir and remove pump.
Fig. 7 Washer Reservoir and Pump
(2) Disconnect hose from pumps.
(3) Drain washer reservoir.
(4) Using a deep socket, remove filter nuts from bottom inside of reservoir and remove pump.
(5) Reverse the removal procedures to install a new pump.
DIAGNOSING WINDSHIELD WIPERS
(1) Remove in-line circuit breaker near fuse block and turn ignition switch to ACCESSORY or ON.
• Measure voltage at battery side of circuit breaker cavity. Meter should read battery voltage. If not, repair wiring from ignition switch.
• Measure resistance across circuit breaker terminals. Meter should read zero ohms. If not, replace failed circuit breaker.
(2) Unplug wiper motor side wiring harness connector from wiper switch side harness connector
(non-intermittent), or from intermittent wiper module at base of steering column. Turn ignition switch to ACCESSORY or ON.
8K - 4 WINDSHIELD WIPERS
J
• Measure voltage at unplugged wiper motor side harness connector terminal D. Meter should read battery voltage. If not, repair wiring from circuit breaker.
• Turn ignition switch to OFF and measure resistance from unplugged wiper motor side harness connector terminal G to ground. Meter should read zero ohms. If not, repair wiring to ground.
(3) Leave ignition switch in OFF, and back probe wiring harness connector at wiper motor (Fig. 8).
Measure resistance from terminal 4 of wiper motor side of connector to ground. Meter should read zero ohms. If not, repair wiring to ground.
(4) If equipped with intermittent wipers, turn ignition switch to ACCESSORY or ON. Turn wiper switch to LOW or HIGH. Unplug wiring harness connector (wiper switch side) from intermittent wiper module. Then plug both connectors that have been removed from intermittent wiper module into each other.
CAUTION: DO NOT move the wiper switch to DE-
LAY with the intermittent wiper module removed from the circuit. If the switch is moved to the DE-
LAY position during the next step, the switch will be damaged.
• Test wiper operation in LOW and HIGH speed modes, and test washer operation. If these modes were inoperative, but are OK now, replace failed intermittent wiper module.
(4) To test the wiper/washer switch, see Wiper
Switch Testing. Turn ignition switch to OFF. Position the wiper switch as indicated, and back probe switch side of wiper switch connector. If switch tests
OK, go to step 5. If not, replace switch and go to step
6.
(5) To further test the wiper/washer switch, turn ignition switch to ACCESSORY or ON. Position the wiper switch as indicated in the tests below, and back probe switch side of wiper switch connector.
• Measure voltage at terminal E with wiper switch in LOW, MIST and with washer switch depressed.
Meter should read battery voltage. If not, replace switch.
• Measure voltage at connector terminal C with wiper switch in HIGH. Meter should read battery voltage. If not, replace switch.
• With wiper switch in LOW or HIGH, measure voltage at connector terminal F, then move wiper switch to OFF. Meter shold read battery voltage until wipers park and then zero volts. If OK, go to step
6. If not, check wiring to wiper motor, then go to step
6.
(6) To test the wiper motor, turn the ignition switch to ACCESSORY or ON. Position the wiper switch and back probe the motor connector (Fig. 8) as indicated.
Fig. 1 Windshield Wiper Connector
• Wiper switch in any position, measure voltage at terminal 1. Meter should read battery voltage. If not, repair wiring from circuit breaker.
• Wiper switch in LOW, measure voltage at terminal 5. Meter should read battery voltage. If OK, but wipers do not operate, replace failed wiper motor. If not, repair wiring from switch or intermittent wiper module connector.
• Wiper switch in HIGH, measure voltage at terminal 6. Meter should read battery voltage. If OK, but wipers do not operate, replace failed wiper motor. If not, repair wiring from switch or intermittent wiper module connector.
• Wiper switch in LOW or HIGH, voltmeter connected to terminal 2. Turn wiper switch to OFF and observe meter. Meter should read battery voltage when switch goes to OFF, then zero volts after wipers park. If battery voltage is present, but wipers fail to park; or, if no battery voltage present, replace failed wiper motor.
DIAGNOSING WINDSHIELD WASHER (NON-
INTERMITTENT)
(1) Unplug washer pump connector.
• Measure resistance between terminal A at pump and a clean chassis ground. Meter should read zero ohms. If not, repair open to ground.
(2) Turn ignition switch to ACCESSORY and washer switch to ON.
• Measure voltage at washer pump connector terminal B. Meter should read battery voltage. If OK, replace washer pump. If not, go to next step.
J
• Measure voltage at wiper/washer switch connector terminal B. Meter should read battery voltage. If
OK, repair open to washer pump. If not, replace switch.
DIAGNOSING WINDSHIELD WASHER
(INTERMITTENT)
(1) Unplug washer pump connector.
• Measure resistance between terminal B at pump and a clean chassis ground. Meter should read zero ohms. If not, repair open to ground.
(2) Turn ignition switch to ACCESSORY and washer switch to ON.
• Measure voltage at wipe module switch connector terminal B (pink wire). Meter should read battery voltage. If not, replace wiper switch.
• Measure voltage at wipe module motor connector terminal B (brown wire). Meter should read battery voltage. If not, replace module.
• Measure voltage at washer pump connector terminal A at pump. Meter should read battery voltage. If
OK, replace pump. If not, repair open from wipe module.
INTERMITTENT WIPER MODULE
The intermittent wiper module is non-serviceable.
Refer to the wiring schematic for connector call outs.
The intermittent wiper module is attached to the lower instrument panel cover near the steering column with a patch of velcro.
LIFTGATE WIPER
GENERAL
The rear wiper motor contains electronic controls to provide three operating modes.
•
Intermittent wipe with a 5 to 8 second delay between sweeps.
•
Constant wipe that operates in conjunction with a washer.
• Park mode that operates when ignition or rear wiper switch is turned OFF.
The rear wiper switch is located in the instrument panel and is supplied current when the ignition switch is in the ON position. When the switch is placed in the intermittent wipe position it provides current to the rear wiper motor. When it is held in the wash/wipe position it provides current to both the motor and the rear washer pump. The switch is spring loaded in the wash/wipe position.
REMOVAL
(1) Remove the wiper arm assembly from the pivot pin by depressing the tab (Fig. 1) and pulling straight out.
(2) Slide clip along hose until clip is off hose mounting.
(3) Disconnect the washer hose.
WINDSHIELD WIPERS
Fig. 1 Rear Wiper Arm Removal
8K - 5
Fig. 2 Rear Wiper Motor Removal/Installation
(4) Remove pivot pin retaining nut.
(5) Remove external bezel and seal.
(6) Remove the liftgate interior trim panel.
(7) Disconnect the wiper motor at the wiring harness.
(8) Remove the wiper motor mounting screws.
(9) Remove the wiper motor.
INSTALLATION
(1) Position the motor (Fig. 2) in the liftgate cavity with the pivot pin protruding through the hole in the liftgate.
8K - 6 WINDSHIELD WIPERS
(2) Install the mounting screws.
(3) Connect the wiring harness.
(4) Install the pivot pin, seal, bezel and attaching nut (Fig. 2). Torque nut to 4 N z m (32 in. lbs.).
(5) Connect interior washer hose.
Lubricate the bezel nipples with a small amount of water and then install the washer hoses.
(6) Install the liftgate trim panel.
(7) Install the wiper arm assembly and connect the external washer hose to the bezel.
(8) Slide the clip along the hose until it is over hose mount.
The blade should be parallel to window opening and no closer than 5mm to window seal when operated on a wet window (Fig. 3).
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Fig. 3 Rear Wiper Arm Positioning
WASHER PUMP REPLACEMENT
The washer pump for the liftgate is located next to the front washer pump on the washer reservoir in the engine compartment. For replacement refer to the front washer pump replacement procedure.
LIFTGATE WIPER SWITCH REPLACEMENT
(1) Remove the instrument panel bezel; see Instrument Panel and Components Section for the procedure.
(2) Remove the switch housing panel.
(3) Unplug the switch connector. Slightly depress the switch mounting tabs and remove the switch
(Fig. 4).
DIAGNOSING REAR WIPER
(1) Remove and inspect 25 amp, #1 fuse. Replace as required.
(2) Turn ignition switch to ACCESSORY and rear wiper switch to WASH.
• Measure voltage at rear wiper switch terminal B.
Meter should read battery voltage. If not, repair open to #1 fuse.
• Measure voltage at rear wiper switch terminals A,
C and D. Meter should read battery voltage. If not, replace switch.
Fig. 4 Rear Wiper Switch
(3) Turn ignition switch to ACCESSORY, place rear wiper switch in WIPE. Measure voltage at rear wiper switch terminal C. Meter should read battery voltage. If not, replace switch.
(4) Remove liftgate cover and measure resistance from rear wiper motor terminal 1 to a good ground.
Meter should read zero ohms. If not, repair open to ground splice.
(5) Turn ignition switch to ACCESSORY and rear wiper switch to WASH.
• Measure voltage at motor connector terminals 2, 3 and 4. Meter should read battery voltage. If OK, replace wiper motor. If not, repair open(s) to rear wiper switch.
DIAGNOSING REAR WIPER WASHER
(1) Turn ignition switch to ACCESSORY and place rear wiper/washer switch in WASH.
• Operate rear wiper motor. If motor does not operate check the 25 amp #1 fuse.
(2) Turn ignition switch to ACCESSORY and unplug rear washer pump connector.
• Measure resistance at pump connector terminal B
(ignition switch OFF). Meter should read zero ohms.
If not, repair open to ground.
• Measure voltage at pump connector terminal A, switch in WASH. Meter should read battery voltage.
If OK, replace pump. If not, go to step 3.
(3) Remove switch and reconnect below instrument panel. Backprobe switch connector with ignition switch in ACCESSORY.
• Measure voltage at switch connector terminal B.
Meter should read battery voltage. If not, repair open to fuse.
• Measure voltage at switch connector terminal A, switch in WASH. Meter should read battery voltage.
If not, replace switch.
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REAR WIPER/WASHER SWITCH TESTING
WINDSHIELD WIPERS 8K - 7
TORQUE SPECIFICATIONS XJ
8K - 8 WINDSHIELD WIPERS
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YJ
INDEX
page
Diagnosing Windshield Wipers
. . . . . . . . . . . . . . . 11
Diagnosing Intermittent Windshield Washer
Diagnosing Non-Intermittent Windshield Washer
Diagnosing Rear Wiper/Washer
. . . . . . . . . . . . . . 14
Front Wiper Arm and Pivot Assembly Replacement . 9
Front Wiper Arm Replacement
. . . . . . . . . . . . . . . 8
Front Wiper Blade Replacement
Front Wiper Motor
. . . . . . . . . . . . . . . . . . . . . . . . 10
page
Front Wipers/Washers General Information
Rear Washer Pump Replacement
Rear Wiper Arm Replacement
. . . . . . . . . . . . . . . 12
Rear Wiper Motor Replacement
. . . . . . . . . . . . . . 13
Rear Wiper Switch Replacement
Rear Wiper/Washer Switch Testing
Washer Nozzle Replacement
. . . . . . . . . . . . . . . . 13
Washer Pump Replacement
. . . . . . . . . . . . . . . . 11
FRONT WIPERS/WASHERS GENERAL
INFORMATION
The non-intermittent windshield wiper circuit contains three components; control switch, motor and washer pump. The intermittent circuit contains the same components and a wiper module that provides the delay function. Both circuits receive battery feed from and are protected by a 5.3 amp circuit breaker.
In the non-intermittent wiper circuit, the switch connects the motor directly to ignition feed for low and high speed operation. In the intermittent circuit, the switch supplies ignition feed to the delay module, which then supplies the motor. In the delay position, the module is connected with the variable resistor in the wiper switch. The value of the resistance is used by the solid state module to charge a capacitor, which triggers the amount of delay between wipes.
The wiper motor has an arrangement of brushes providing the two wiper speeds. When the wipers are turned off, the park switch maintains current to the motor until the wipers reach the park position on the windshield.
The washer pump receives ignition feed either directly from the wiper switch or from the intermittent module. In either case the electric motor will drive the washer pump.
The wiper motor is mounted on the lower left corner of the windshield.
FRONT WIPER BLADE REPLACEMENT
Rotate the wiper blade release (Fig. 1) clockwise.
This will release the wiper blade from the pivot pin.
CAUTION: Take care to ensure that the wiper arm does not strike the windshield after the wiper blade has been removed.
To install, place the blade assembly on the wiper arm and snap the blade assembly into position.
FRONT WIPER ARM REPLACEMENT
(1) Pull the wiper arm forward.
2).
(2) Insert an ice pick type tool into the hole (Fig.
Fig. 1 Wiper Blade Removal
Fig. 2 Wiper Arm Removal/Installation
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(3) Grasp the wiper arm above the pivot nut.
(4) Pull and remove the wiper arm assembly.
(5) To install, push the wiper arm over the pivot shaft. Be sure the pivot shaft is in the park position and the wiper arm is positioned correctly on the windshield (Fig. 3).
WINDSHIELD WIPERS 8K - 9
Fig. 4 Remove Wiper Motor Mounting Screws
Fig. 3 Wiper Arm Positioning
FRONT WIPER ARM AND PIVOT ASSEMBLY
REPLACEMENT
REMOVAL
(1) Remove the left and right wiper arms.
(2) Remove the nuts attaching the pivots to the windshield frame.
(3) Remove the necessary hard or soft top components from the windshield frame.
(4) Remove the windshield holddown bolts in the lower corners of the instrument panel and fold the windshield forward.
(5) Remove wiper motor mounting screws (Fig. 4).
(6) Disconnect wiper linkage drive arm (Fig. 5).
(7) Remove motor wiring clip from base of windshield frame.
(8) Remove 4 inboard screws holding seal to bottom of windshield frame (protruding screw ends interfere with pivot link removal and installation).
(9) Grasp motor and pull motor and drive arm out of access hole (Fig. 6).
(10) Remove pivot shaft assembly through access hole.
(11) Pry drive arm off the motor pivot. DO NOT remove pivot attaching nut (Fig. 7).
Fig. 5 Disconnect Drive Arm
INSTALLATION
(1) Install wiper linkage drive arm onto motor
(Fig. 8).
(2) Install pivot shaft assembly in windshield frame.
(3) Install motor and drive arm in windshield frame.
(4) Install weatherstrip screws.
(5) Connect wiper linkage drive arm to pivot shaft
(Fig. 9).
8K - 10 WINDSHIELD WIPERS
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Fig. 6 Remove Wiper Motor and Drive Arm
Fig. 8 Install Drive Arm On Motor
Fig. 7 Drive Arm Removal
(6) Install motor mounting screws. Tighten screws to 10.5 N z m (96 in. lbs.).
Be sure wire harness is not pinched or cut when windshield frame is rotated to upright position.
(7) Raise windshield to upright position and install left and right windshield holddown bolts.
(8) Install nuts attaching pivots to windshield frame. Tighten nuts to 10 N z m (7.5 ft. lbs.).
Fig. 9 Connect Drive Arm To Pivot Shaft
(9) Turn wipers on to allow motor to cycle to park position.
(10) Install left and right wiper arms (Fig. 3).
(11) Install necessary top components on windshield frame.
FRONT WIPER MOTOR
REMOVAL
(1) Remove the necessary hard or soft top components from the windshield frame.
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WINDSHIELD WIPERS 8K - 11
(2) Remove the windshield holddown bolts in the lower corners of the instrument panel.
(3) Remove wiper motor mounting screws (Fig. 4).
(4) Remove wiper motor harness retaining clip located on bottom of windshield.
(5) Disconnect the wiper linkage drive arm (Fig. 5)
(6) Grasp the motor and pull the motor and drive arm out of the access hole (Fig. 6).
(7) Pry the drive arm off the motor pivot. DO NOT remove the pivot attaching nut (Fig. 7).
(8) Remove 2 screws holding intermittent wipe module bracket to bottom of instrument panel.
(9) Reach up behind instrument panel and disconnect wiper motor harness.
(10) Remove wiper motor.
INSTALLATION
(1) Install wire harness through hole in top of instrument panel.
(2) Connect wiper motor connector behind instrument panel.
(3) Install intermittent wipe module bracket to bottom of instrument panel.
(4) Turn wipers on to allow motor to cycle to park position.
(5) Install wiper linkage drive arm onto motor
(Fig. 8).
(6) Install motor and drive arm in the windshield frame.
(7) Connect wiper linkage drive arm to pivot shaft
(Fig. 9).
(8) Install motor mounting screws. Tighten screws to 10.5 N z m (96 in. lbs.).
(9) Install wire harness retaining clip on bottom of windshield.
Be sure wire harness is not pinched or cut when windshield frame is rotated to upright position.
(10) Raise windshield to upright position and install left and right windshield holddown bolts.
(11) Install the necessary top components on windshield frame.
WASHER PUMP REPLACEMENT
(1) Remove 3 washer reservoir mounting screws
(Fig. 10).
(2) Disconnect hose(s) from pump.
(3) Drain washer reservoir.
(4) Using a deep socket, remove filter nut from bottom inside reservoir and remove pump.
(5) Reverse the removal procedure to install a new pump.
DIAGNOSING WINDSHIELD WIPERS
(1) Remove in-line circuit breaker near fuse block and turn ignition switch to ACCESSORY or ON.
Fig. 10 YJ Washer Reservoir and Pump
• Measure voltage at battery side of circuit breaker cavity. Meter should read battery voltage. If not, repair wiring from ignition switch.
• Measure resistance across circuit breaker terminals. Meter should read zero ohms. If not, replace failed circuit breaker.
(2) Unplug wiper motor side wiring harness connector from wiper switch side harness connector
(non-intermittent), or from intermittent wiper module at base of steering column. Turn ignition switch to ACCESSORY or ON.
• Measure voltage at unplugged wiper motor side harness connector terminal D. Meter should read battery voltage. If not, repair wiring from circuit breaker.
• Turn ignition switch to OFF and measure resistance from unplugged wiper motor side harness connector terminal G to ground. Meter should read zero ohms. If not, repair wiring to ground.
(3) Leave ignition switch in OFF, and back probe wiring harness connector at wiper motor. Measure resistance from terminal E of wiper motor side of connector to ground. Meter should read zero ohms. If not, repair wiring to ground.
(4) If equipped with intermittent wipers, turn ignition switch to ACCESSORY or ON. Turn wiper switch to LOW or HIGH. Unplug wiring harness connector (wiper switch side) from intermittent wiper module. Then plug both connectors that have been removed from intermittent wiper module into each other.
8K - 12 WINDSHIELD WIPERS
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CAUTION: DO NOT move the wiper switch to DE-
LAY with the intermittent wiper module removed from the circuit. If the switch is moved to the DE-
LAY position during the next step, the switch will be damaged.
• Test wiper operation in LOW and HIGH speed modes, and test washer operation. If these modes were inoperative, but are OK now, replace failed intermittent wiper module.
(4) To test the wiper/washer switch, see Wiper
Switch Testing. Turn ignition switch to OFF. Position the wiper switch as indicated, and back probe switch side of wiper switch connector. If switch tests
OK, go to step 5. If not, replace switch and go to step
6.
(5) To further test the wiper/washer switch, turn ignition switch to ACCESSORY or ON. Position the wiper switch as indicated in the tests below, and back probe switch side of wiper switch connector.
• Measure voltage at terminal E with wiper switch in LOW, MIST and with washer switch depressed.
Meter should read battery voltage. If not, replace switch.
•
Measure voltage at connector terminal C with wiper switch in HIGH. Meter should read battery voltage. If not, replace switch.
• With wiper switch in LOW or HIGH, measure voltage at connector terminal F, then move wiper switch to OFF. Meter shold read battery voltage until wipers park and then zero volts. If OK, go to step
6. If not, check wiring to wiper motor, then go to step
6.
(6) To test the wiper motor, turn the ignition switch to ACCESSORY or ON. Position the wiper switch and back probe the motor connector as indicated.
•
Wiper switch in any position, measure voltage at terminal B. Meter should read battery voltage. If not, repair wiring from circuit breaker.
• Wiper switch in LOW, measure voltage at terminal A. Meter should read battery voltage. If OK, but wipers do not operate, replace failed wiper motor. If not, repair wiring from switch or intermittent wiper module connector.
• Wiper switch in HIGH, measure voltage at terminal H. Meter should read battery voltage. If OK, but wipers do not operate, replace failed wiper motor. If not, repair wiring from switch or intermittent wiper module connector.
• Wiper switch in LOW or HIGH, voltmeter connected to terminal D. Turn wiper switch to OFF and observe meter. Meter should read battery voltage when switch goes to OFF, then zero volts after wipers park. If battery voltage is present, but wipers fail to park; or, if no battery voltage present, replace failed wiper motor.
DIAGNOSING NON-INTERMITTENT WINDSHIELD
WASHER
Refer to Group 8W - Wiring Diagrams.
(1) Measure resistance from washer pump connector terminal B to a clean chassis ground. Meter should read zero ohms. If not, repair open between terminal B and ground.
(2) Turn ignition switch to ON and press washer switch.
•
Measure voltage at switch connector terminal B.
Meter should read battery voltage. If not, replace wiper/washer switch.
• Measure voltage at washer pump connector terminal A. Meter should read battery voltage. If OK, replace pump. If not, repair open between switch connector and pump connector.
DIAGNOSING INTERMITTENT WINDSHIELD
WASHER
Refer to Group 8W - Wiring Diagrams.
(1) Measure resistance from washer pump connector terminal B to a clean chassis ground. Meter should read zero ohms. If not, repair open between terminal B and ground.
(2) Turn ignition switch to ON and rotate washer switch tab forward.
• Measure voltage at wiper/washer switch connector terminal B located at intermittent wipe module.
Meter should read battery voltage. If not, replace wiper switch.
• Measure voltage at intermittent wipe module connector terminal B (to washer pump). Meter should read battery voltage. If not, replace intermittent wipe module.
•
Measure voltage at washer pump connector terminal A. Meter should read battery voltage. If OK, replace pump. If not, repair open from intermittent wipe module connector terminal B.
REAR WIPER ARM REPLACEMENT
(1) Install wiper arm remover, Snap On A192 or equivalent, on wiper arm (Fig. 11). Lift arm and then remove from pivot shaft.
CAUTION: Do not use a screwdriver or other prying tool to remove an arm. This may distort it in a way that will allow it to come off the pivot shaft in the future, despite how carefully it is installed. NEVER push or bend the spring clip in the base of the arm in an attempt to release the arm. This clip is self releasing.
(2) To install, reverse the removal procedure.
(3) Wet the window and check the park position by operating the wiper motor several times.
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WINDSHIELD WIPERS 8K - 13
Fig. 11 Removing Liftgate Wiper Arm
REAR WASHER PUMP REPLACEMENT
The washer pump for the rear window is located next to the front washer pump on the washer reservoir in the engine compartment (Fig. 12). For replacement refer to the front washer pump replacement procedure.
Fig. 13 Rear Wiper Switch
REAR WIPER MOTOR REPLACEMENT
(1) Remove wiper arm from motor (refer to Wiper
Arm Replacement).
(2) Remove pivot shaft retaining nut.
(3) Remove motor trim cover (Fig. 14).
Fig. 12 Rear Washer Pump
REAR WIPER SWITCH REPLACEMENT
(1) Remove the instrumentation shroud; see Instrument Panel, Indicator Bezel Replacement.
(2) Remove the switch housing panel.
(3) Unplug the switch connector. Slightly depress the switch mounting tabs and remove the switch
(Fig. 13).
Fig. 14 Rear Wiper Motor Cover
(4) Disconnect electrical connector (Fig. 15).
(5) Remove hinge nut holding motor to top.
(6) To install, reverse the removal procedures.
WASHER NOZZLE REPLACEMENT
(1) From inside the vehicle remove the motor trim cover.
(2) Remove the washer hose from the back of the washer nozzle.
(3) Remove the nut holding the nozzle to the glass.
(4) Install the new washer nozzle.
8K - 14 WINDSHIELD WIPERS
REAR WIPER/WASHER SWITCH TESTING
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Fig. 15 Rear Wiper Motor
DIAGNOSING REAR WIPER/WASHER
Refer to Group 8W - Wiring Diagrams.
(1) Turn ignition switch to ON and rear wiper/ washer switch to WASH.
• Measure voltage at switch connector terminal P.
Meter should read battery voltage. If not, check 20 amp, fuse #1.
•
Measure voltage at switch connector terminal B.
Meter should read battery voltage. If not, replace switch.
• Measure voltage at switch connector terminal A.
Meter should read battery voltage. If not, replace switch.
(2) Turn ignition switch to ON and unplug rear washer pump connector.
• Measure resistance at pump connector black wire to ground. Meter should read zero ohms (ignition
OFF). If not, repair open to ground.
• Measure voltage at pump connector brown/white wire, switch in WASH. Meter should read battery voltage. If OK, replace pump. If not, check wiring.
(3) Turn ignition switch to ON, unplug rear wiper motor connector and place wiper switch in WIPE.
• Measure resistance at motor connector terminal B to ground. Meter should read zero ohms. If not, repair open to ground.
• Measure voltage at motor connector terminal A.
Meter should read battery voltage. If not, check wiring to fuse.
• Measure voltage at motor connector terminal C.
Meter should read battery voltage. If OK, replace motor. If not, repair open to switch.
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WINDSHIELD WIPERS 8K - 15
WIPER CONTROL SWITCH REPLACEMENT
(1) Disconnect negative cable from battery.
(2) Remove horn button with a push and turn motion.
(3) Remove horn button components (Fig. 1).
Fig. 1 Steering Wheel Removal/Installation
(4) Turn ignition switch to the LOCK position and remove the steering wheel nut and washer.
(5) Scribe an alignment mark on the steering in line with the mark already existing on the end of the steering column.
(6) Remove vibration damper from the steering column hub, if equipped.
(7) Remove steering wheel using a steering wheel puller. DO NOT hammer on puller or end of steering shaft.
WARNING: TO REMOVE THE STEERING SHAFT
SNAP RING IN THE FOLLOWING STEP, THE LOCK-
PLATE MUST BE COMPRESSED. DO NOT AT-
TEMPT TO REMOVE THE LOCKPLATE WITHOUT
COMPRESSOR TOOL C4156 AS THE LOCKPLATE
IS UNDER HEAVY SPRING TENSION.
(8) Compress lockplate with compressor tool
C4156.
(9) Remove steering shaft snap ring (Fig. 2). Discard snap ring. It is not reusable.
(10) Remove compressor tool.
(11) Remove lockplate, cancelling cam, and upper bearing preload spring.
(12) Remove horn button components from canceling cam.
Fig. 2 Lockplate Removal
(13) Remove screw and hazard warning switch knob.
(14) Remove dimmer switch actuator arm attaching screw (Fig. 3).
Fig. 3 Turn/Hazard Switch And Dimmer Actuating
Arm Screws
(15) Remove turn/hazard switch attaching screws
(Fig. 3).
(16) XJ Remove lower instrument panel cover trim panel.
8K - 16 WINDSHIELD WIPERS
(17) YJ
(a) Remove 6 shroud screws (Fig. 4).
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Fig. 4 Instrument Shroud Removal/Installation—YJ
(b) Slide shroud toward steering wheel.
(18) Remove cover under column.
(19) If vehicle is equipped with a column shift, remove PRNDL cable clip (Fig. 5).
Fig. 6 Lower Steering Column Mounting
(22) Loosen column brace mounting nut at drivers side kick panel. This will allow column to drop.
(23) Unplug wiper switch connector.
(24) Tape connector to wires (Fig. 7).
Fig. 5 PRNDL Cable Clip Removal/Installation
(20) Remove 2 nuts holding steering column bracket to brake sled (Fig. 6).
(21) Remove 4 bolts holding steering column brace to column.
Fig. 7 Tape Wiper Switch Connector
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WINDSHIELD WIPERS 8K - 17
(25) Push turn/hazard connector up and out of steering column connector (Fig. 8).
(29) Insert ignition key in lock cylinder and turn ignition switch to ON position.
(30) Remove key warning buzzer switch and retaining clip with a paper clip inserted below retainer so that retainer is flattened (Fig. 10).
Do not attempt to remove buzzer switch and clip separately. The clip could fall into the column jacket.
Fig. 8 Turn/Hazard Switch And Steering Column
Connectors
(26) Pry up locking tabs of steering column connector and remove connector from column bracket.
(27) Remove plastic harness cover by pulling it up and over weld nuts then open and slide the cover off harness (Fig. 9).
Fig. 10 Buzzer Switch Removal
(31) Remove ignition lock cylinder retaining screw and pull lock cylinder out of column housing (Fig. 11).
Fig. 9 Remove Plastic Harness Cover
(28) Pull turn/hazard switch out of column far enough to allow access to remaining screws.
Fig. 11 Lock Cylinder Removal/Installation
8K - 18 WINDSHIELD WIPERS
(32) Remove screws that attach housing and shroud assembly to column jacket and carefully remove housing and shroud assembly (Fig. 12).
DO NOT let dimmer switch rod, lock pin or lock rack fall out.
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Fig. 13 Remove Pivot Screw
Fig. 12 Steering Column Housing
Removal/Installation
(33) Remove turn/hazard/wiper lever by pulling it straight out of column.
(34) Remove wiper switch cover from back of housing and shroud assembly (Fig. 13). If equipped with column shift, remove screw holding the cover on.
(35) Remove pivot screw from housing and remove wiper switch.
(36) Install a new switch and switch cover.
(37) Push on dimmer switch rod to make sure it is connected then carefully position housing and shroud assembly to column (Fig. 14).
Make sure nylon spring retainer on lock pin is positioned forward of the retaining slot of lock rack (Fig. 14).
Position first tooth of gear (farthest from the block tooth) with the most forward tooth of lock rack.
(38) Install screws that attach housing and shroud assembly to column jacket and carefully mate housing and shroud assembly.
(39) Insert key and lock cylinder and test that lock pin extends fully when key is moved to lock position.
(40) To install remaining parts, reverse removal procedures.
Fig. 14 Check Dimmer Switch Rod and Lock Pin
CAUTION: When installing a wiper switch, make sure wires are laying flat on bottom inside of column.
On vehicles equipped with column shift, install
PRNDL cable clip with shift indicator on N (neutral). Move selector through the range and make sure it lines up with each letter.
(41) Install steering wheel. Tighten steering wheel nut to 34 N z m (25 ft. lbs.) torque.
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STANDARD WIPER WASHER
WIPER SWITCH TESTING
WINDSHIELD WIPERS 8K - 19
8K - 20 WINDSHIELD WIPERS
INTERMITTENT WIPER WASHER
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LAMPS 8L - 1
LAMPS
CONTENTS page
EXTERIOR LAMPS
. . . . . . . . . . . . . . . . . . . . . . . 1
INTERIOR LAMPS
. . . . . . . . . . . . . . . . . . . . . . 19
page
SPECIFICATIONS
. . . . . . . . . . . . . . . . . . . . . . . 23
EXTERIOR LAMPS
INDEX
page
Back-up/Rear Turn Signal/Tail Lamp Bulb
Replacement
. . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Center High Mounted Stop Lamp (CHMSL)—XJ
Center High Mounted Stop Lamp (CHMSL)—YJ
Daytime Running Lights (Canada Only)
DRL Module Replacement
. . . . . . . . . . . . . . . . . . 16
Fog Lamp Beam Adjustment
. . . . . . . . . . . . . . . . 12
Fog Lamp Bulb/Element Replacement
Fog Lamp Replacement
. . . . . . . . . . . . . . . . . . . 15
Fog Lamp Service Information
. . . . . . . . . . . . . . . 12
Fog Lamp Switch Replacement
. . . . . . . . . . . . . . 14
Fog Lamp Trouble Diagnosis
. . . . . . . . . . . . . . . . 12
Front Park/Turn Signal Lamp Bulb Replacement
Headlamp Beam Adjustment
. . . . . . . . . . . . . . . . . 3
Headlamp Bulb Replacement
. . . . . . . . . . . . . . . . 3
Headlamp Delay Function Trouble Diagnosis—XJ
Vehicles
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
page
Headlamp Delay Module Replacement—XJ
Vehicles
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Headlamp Dimmer Switch Replacement
Headlamp Switch Replacement
. . . . . . . . . . . . . . . 4
Headlamp Trouble Diagnosis—XJ Vehicles
Headlamp Trouble Diagnosis—YJ Vehicles
License Plate Lamp
. . . . . . . . . . . . . . . . . . . . . . . 10
Sentinel Headlamp Delay Module—XJ Vehicles
Service Information
. . . . . . . . . . . . . . . . . . . . . . . . 1
Side Marker Lamp Bulb Replacement
Switch Tests
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Underhood Lamp Bulb Replacement
Underhood Lamp Replacement
. . . . . . . . . . . . . . 18
Underhood Lamp Service Information
SERVICE INFORMATION
Exterior lamp circuits are comprised of the headlamp circuit, fog lamp circuit, and tail/side marker/ park lamp circuit. Battery voltage is controlled by both the headlamp ON/OFF switch and headlamp dimmer switch.
The dimmer switch functions as a fog lamp switch.
Voltage is applied to the fog lamp switch only when the dimmer switch is in the low beam position.
HEADLAMP TROUBLE DIAGNOSIS—XJ VEHICLES
LOW AND HIGH BEAM INOPERATIVE BOTH
HEADLAMPS
(1) Place the headlamp switch in the ON position.
(2) Test the 40 amp fuse for continuity. If bad, replace fuse.
(3) Insert the test probe into terminal 5 of the front lamp wire harness connector. Measure the resistance from terminal 5 to body ground. The ohmmeter should indicate zero ohms. If not OK, repair the open circuit in the harness to body ground.
(4) Disconnect the front lamp wire connector. Measure resistance between connector terminals 5 and 2.
Next measure between terminal 5 and 7. The ohmmeter should indicate zero ohms for both measurements. If not OK, replace the headlamp bulbs.
(5) Measure the voltage between the dimmer switch wire connector terminal 2 and body ground.
The voltmeter should indicate battery voltage. If not
OK, continue with the next step.
The dimmer switch is integral with the turn signal and is located on the steering column.
The dimmer switch switches the headlamp beam when the turn signal lever is pulled rearward.
(6) Disconnect the dimmer switch wire connector and place the headlamp switch in the OFF position.
Measure the resistance from terminal 2 to vehicle body ground. The ohmmeter should indicate infinite resistance. If OK, replace the headlamp switch and continue with the next step. If not OK, repair the short circuit in the wire harness that leads to terminal 2.
8L - 2 LAMPS
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(7) Measure the resistance from the dimmer switch wire harness connector terminal 1 to vehicle body ground. The ohmmeter should indicate zero ohms. If
OK, continue with the next step. If not OK, repair the short circuit in the wire harness that leads to terminal 1.
(8) Measure the resistance from the dimmer switch wire harness connector terminal 3 to vehicle body ground. The ohmmeter should indicate zero ohms. If
OK, test the dimmer switch. Replace, if defective.
Connect the wire harness connector to the dimmer switch. If not defective, repair the short circuit in the wire harness that leads to terminal 3.
LOW OR HIGH BEAM INOPERATIVE BOTH
HEADLAMPS
(1) Place the headlamp switch in the OFF position.
Disconnect the dimmer switch wire harness connector.
(2) Measure the resistance from the dimmer switch connector terminal 1 to body ground. The ohmmeter should indicate zero ohms. If not OK, repair the open circuit in the wire harness that leads to the headlamp bulbs.
(3) Measure the resistance from the dimmer switch connector terminal 3 to vehicle body ground. The ohmmeter should indicate zero ohms. If OK, replace the dimmer switch. If not OK, repair the open circuit in the wire harness that leads to headlamp bulbs.
HEADLAMP TROUBLE DIAGNOSIS—YJ VEHICLES
(1) Place the headlamp switch in the ON position.
(2) Place the headlamp dimmer switch in the
HIGH or LOW position.
(3) Disconnect the wire harness connectors from the headlamp bulbs.
(4) If applicable, measure voltage between each headlamp bulb wire connector terminal B and vehicle body ground. The voltmeter should indicate battery voltage. If not OK, repair the open circuit in wire harness between connector and dimmer switch.
(5) If applicable, measure the voltage between each headlamp bulb connector terminal C and body ground. The voltmeter should indicate battery voltage. If not OK, repair the open circuit in the wire harness between the connector and the dimmer switch.
(6) Measure the resistance from each headlamp bulb connector terminal A to body ground. The ohmmeter should indicate zero ohms. If not OK, repair the open circuit in the wire harness between the connectors and vehicle body ground.
SWITCH TESTS
HEADLAMP—ALL VEHICLES
(1) Refer to the applicable wiring diagram for terminal reference.
(2) Place the headlamp switch in the ON position.
(3) Measure the voltage between the headlamp switch connector voltage supply terminal and vehicle body ground. The voltmeter should indicate battery voltage. If not OK, repair the open circuit in the wire harness between the fuse and the switch connector terminal.
(4) Measure the voltage between the headlamp switch connector battery voltage OUT terminal and vehicle body ground. The voltmeter should indicate battery voltage. If not OK, replace the headlamp switch.
DIMMER SWITCH—ALL VEHICLES
(1) Place the headlamp switch in the ON position.
Place the dimmer switch in the HIGH or LOW beam position, as applicable.
(2) Measure the voltage between the dimmer switch connector voltage supply terminal and vehicle body ground. The voltmeter should indicate battery voltage. If not OK, repair the open circuit in the wire harness between the headlamp switch and the dimmer switch.
Fig. 1 Headlamp Dimmer Switch Terminals
(3) Place the dimmer switch in the LOW beam position. Measure the voltage between the dimmer switch connector low beam voltage OUT terminal and body ground. The voltmeter should indicate battery voltage. If not OK, replace the dimmer switch.
(4) Place the dimmer switch in the HIGH beam position. Measure the voltage between the dimmer switch connector high beam voltage OUT terminal and body ground. Voltmeter should indicate battery voltage. If not OK, replace dimmer switch.
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LAMPS 8L - 3
HEADLAMP BULB REPLACEMENT
REMOVAL
(1) Remove the screws and the headlamp bezel
(Figs. 2 and 3).
INSTALLATION
(1) Position the bulb in the bucket and connect the wire harness connector.
(2) Position retaining ring on the headlamp bulb and install screws.
(3) Install the headlamp bezel. Tighten the screws securely.
HEADLAMP BEAM ADJUSTMENT
SERVICE INFORMATION
The following headlamp beam adjustment procedures apply to all Jeep t vehicles. The headlamp beam must be adjusted with the headlamps on LOW beam. The headlamp beam can be adjusted either with the use of mechanical headlamp aimers or by the use of an aiming screen (Fig. 4).
Fig. 2 Headlamp Components—XJ Vehicles
Fig. 3 Headlamp Components—YJ Vehicles
(2) Remove the screws and headlamp bulb retaining ring.
(3) Disconnect the headlamp bulb wire harness connector and remove the bulb from the bucket.
Fig. 4 Headlamp ‘‘Aiming’’ Screen
ADJUSTMENT WITH MECHANICAL AIMERS
Use Headlamp Aimer C-4466-A (J25300-A) and follow instructions supplied with equipment.
Adjust headlamps so that the beam horizontal position is at 0 and beam vertical position is 25 mm (1 in) downward.
ADJUSTMENT WITH AIMING SCREEN
PREPARATION
When an aiming screen is to be used for headlamp aim adjustment, use following procedure.
(1) Position the vehicle in dark area with a level floor and with a screen (wall) that has a white surface.
(2) Refer to Figure 4. Mark a reference line (2) on the floor 7.62 meters (25 feet) away from and parallel to the screen/wall (1).
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(3) Move vehicle with the headlamps located directly above the 7.62-meters (25-feet) reference line.
(4) Equalize all the tire pressures.
(5) Rock vehicle from side to side to stabilize the springs and shock absorbers.
(6) Use tape to attach a vehicle centerline on the screen/wall (6). Ensure that it is aligned with and represents the centerline of the vehicle.
(7) Measure distance between the vehicle headlamp centers. Divide this distance by two. Measure the one/half distance outward from each side of the vehicle centerline (6). Use tape to attach the right and left lamp vertical centerline (4 and 5) on the screen/wall (6).
(8) Measure the distance from the center of each headlamp to the floor.
(9) Measure the lamp-to-floor distance upward from the floor at each lamp vertical centerline (4 and
5). Use tape to attach the lamp horizontal centerline
(3) on the screen/wall.
ADJUSTMENT
(1) Remove screws and both headlamp bezels.
(2) Clean front of the headlamps.
(3) Place headlamps on LOW beam.
(4) Cover front of the headlamp that is not being adjusted.
(5) Turn vertical adjustment screw until the headlamp beam pattern on screen/wall is similar to the pattern depicted in Figure 6.
Fig. 5 Headlamp Beam Adjustment Screws—XJ/YJ
Vehicles
When using a headlamp aiming screen:
• adjust the headlamps so that the beam horizontal position is at 0; and
• adjust the beam vertical position is 25 mm (1 in) downward from the lamp horizontal centerline.
Fig. 6 Headlamp Beam Pattern—Typical
(6) Rotate the horizontal adjustment screw until the headlamp beam pattern on the aiming screen/ wall similar to the pattern in Figure 6.
(7) Cover front of the headlamp that has been adjusted and adjust the other headlamp beam as instructed above.
(8) Install headlamp bezels. Tighten the screws securely.
HEADLAMP SWITCH REPLACEMENT
REMOVAL—XJ VEHICLES
(1) Disconnect battery negative cable.
(2) Place headlamp switch control knob in the headlamp ON position.
(3) Depress the switch shaft release/retainer button via the underside of the instrument panel. Pull the switch control shaft knob outward.
(4) Remove the headlamp switch spanner nut from the front of the instrument panel (Fig. 8).
(5) Disconnect the wire harness connector from the switch.
(6) Remove the headlamp switch from the instrument panel.
INSTALLATION—XJ VEHICLES
(1) Install the headlamp switch in the instrument panel and connect the wire harness connector.
(2) Install the headlamp switch spanner nut.
(3) Insert the headlamp switch control shaft in the spanner nut and force it into the switch.
(4) Connect the battery negative cable.
REMOVAL—YJ VEHICLES
(1) Disconnect the battery negative cable.
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LAMPS 8L - 5
Fig. 7 Headlamp Switch Shaft Removal—XJ
Vehicles
Fig. 9 Instrument Panel Shroud—YJ Vehicles
Fig. 8 Headlamp Switch—Typical
9).
(2) Remove the I/P shroud retaining screws (Fig.
(3) Move the I/P shroud toward the steering wheel.
(4) Apply upward force to the I/P shroud and downward force to the indicator panel. This will release the indicator panel holding tabs (Fig. 10).
(5) Remove the shroud from the instrument panel.
(6) Remove the headlamp switch retaining screws
(Fig. 11).
(7) Disconnect the headlamp switch wire harness connector.
(8) Remove the headlamp switch from the instrument panel cavity.
INSTALLATION—YJ VEHICLES
(1) Position headlamp switch in the instrument panel and connect the wire harness connector to the switch.
(2) Install the headlamp switch screws. Tighten the screws.
Fig. 10 Indicator Panel Holding Tabs—YJ Vehicles
(3) Position the I/P shroud under the steering column.
(4) Slide the indicator panel holding tabs into the shroud notches.
(5) Place the assembled I/P shroud over the indicator lamp gasket.
(6) Install and tighten the indicator panel screws.
(7) Install the remaining shroud screws. Tighten the screws.
(8) Connect the battery negative cable.
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Fig. 11 Headlamp Switch—YJ Vehicles
HEADLAMP DIMMER SWITCH REPLACEMENT
REMOVAL
(1) Disconnect battery negative cable.
(2) Remove the lower instrument panel (Fig. 12) and continue with step 4.
Fig. 13 Instrument Panel Shroud—YJ Vehicles
Fig. 12 Lower Instrument Panel—XJ Vehicles
(3) YJ vehicles:
• remove the I/P shroud retaining screws (Fig. 13).
• move the I/P shroud toward the steering wheel;
• apply upward force to the I/P shroud and downward force to the indicator panel — this will release the indicator panel holding tabs (Fig. 14);
• remove the shroud from the instrument panel;
• support the A/C evaporator housing;
• remove the A/C evaporator housing-to-instrument panel screws (Fig. 15);
Fig. 14 Indicator Panel Holding Tabs—YJ Vehicles
• remove the A/C evaporator housing support bracket screw;
• remove the support and lower the A/C evaporator housing; and
• continue with step 4.
(4) Disconnect the dimmer switch wire harness connector.
(5) Tape the dimmer switch actuator rod to the steering column.
(6) Remove the dimmer switch screws and detach the switch from the rod.
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LAMPS 8L - 7
Fig. 15 A/C Evaporator Housing—YJ Vehicles
INSTALLATION
(1) Force the dimmer switch onto the actuator rod and install screws. DO NOT tighten the retaining screws at this time.
(2) Remove the tape attaching the actuator rod to the steering column.
(3) Adjust the dimmer switch as follows:
• compress the switch and insert a 3/32-inch diameter drill bit into the adjustment hole (Fig. 16);
• the drill bit will prevent any horizontal movement of the switch;
(5) YJ vehicles:
• position the I/P shroud under the steering column;
• slide the indicator panel holding tabs (Fig. 14) into the shroud notches;
• place the assembled I/P shroud over the indicator lamp gasket;
• install and tighten screws;
• install and tighten remaining shroud screws;
• raise and support the A/C evaporator housing (Fig.
15); and
• install the evaporator housing-to-instrument panel screws and evaporator support bracket screw.
SIDE MARKER LAMP BULB REPLACEMENT
REMOVAL—XJ VEHICLES
(1) Remove the screws from the side marker lamp lens and housing. Separate lens and housing from the headlamp bezel (Fig. 17).
Fig. 16 Headlamp Dimmer Switch Adjustment
• move the switch toward the steering wheel to remove any existing actuator rod lash;
• tighten screws with 4 N z m (35 in. lbs.) torque.
• connect battery negative cable;
• remove drill bit and test the switch operation; and
• re-adjust the switch, if necessary.
(4) XJ vehicles — install the lower instrument panel (Fig. 12)
Fig. 17 Side Marker Lamp—XJ Vehicles
(2) Remove the bulb and socket from the back side of the lamp housing.
(3) Remove bulb from socket.
INSTALLATION—XJ VEHICLES
(1) Install a replacement bulb in the socket.
(2) Install bulb and socket in the back of side marker lamp housing.
(3) Position the side marker lens and housing on the headlamp bezel (Fig. 17).
(4) Install the side marker lamp screws. Tighten the screws.
REMOVAL—YJ VEHICLES
(1) Remove side marker bulb socket via the underside of the fender. Rotate it one-third turn and separate it from the side marker lamp housing (Fig. 18).
(2) Remove the bulb from the socket by pulling it straight outward.
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Fig. 18 Side Marker Lamp Bulb—YJ Vehicles
INSTALLATION—YJ VEHICLES
(1) Install a replacement bulb in the socket.
(2) Install the bulb and socket in the side marker lamp housing (Fig. 18).
FRONT PARK/TURN SIGNAL LAMP BULB
REPLACEMENT
REMOVAL—XJ VEHICLES
(1) Remove the headlamp bezel screw and the side marker lamp lens/housing screw (Fig. 19).
Fig. 20 Headlamp Bezel Removal/Installation
(3) Remove screws from the park/turn signal lamp housing (Fig. 21).
Fig. 19 Headlamp Bezel & Side Marker Lamp—XJ
Vehicles
(2) Separate the side marker lamp from the headlamp bezel and remove the screws from the headlamp bezel (Fig. 20).
Fig. 21 Park/Turn Signal Lamp Housing Removal
(4) Separate the lamp housing from the headlamp bezel.
(5) Rotate the bulb socket one-third turn and remove it from the lamp housing.
(6) Remove bulb from socket.
INSTALLATION—XJ VEHICLES
(1) Install a replacement bulb in the socket.
(2) Install bulb and socket in the lamp housing.
(3) Position the park/turn signal lamp housing on the headlamp bezel.
(4) Install lamp housing screws.
Tighten the screws.
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(5) Install the outer screws in the headlamp bezel.
Tighten the screws.
(6) Position the side marker lamp lens/housing on the headlamp bezel.
(7) Install side marker lamp lens/housing screws and headlamp bezel (Fig. 19). Tighten the screws.
REMOVAL—YJ VEHICLES
(1) Remove the park/turn signal lamp housing screws (Fig. 22).
LAMPS 8L - 9
Fig. 23 Tail Lamp Housing—XJ Vehicles
(2) Rotate the bulb socket one-third turn and remove the bulb socket from the lamp housing.
Fig. 22 Park/Turn Signal Lamp Bulb
Replacement—YJ Vehicles
(2) Separate the park/turn signal lamp housing from the grille panel.
(4) Turn the bulb socket and remove it from the lamp housing.
(3) Pull the bulb straight out of the socket.
INSTALLATION—YJ VEHICLES
(1) Install a replacement bulb in the socket.
(2) Install the bulb and socket in the lamp housing.
(3) Position the park/turn signal lamp housing at the opening in the grille panel.
(4) Install the lamp housing retaining screws.
Tighten the screws securely.
BACK-UP/REAR TURN SIGNAL/TAIL LAMP BULB
REPLACEMENT
REMOVAL—XJ VEHICLES
(1) Remove the tail lamp housing upper retaining screws. Slide the lamp housing upward off the lower screw and separate it from the rear of the vehicle.
Fig. 24 Bulb Socket Removal—XJ Vehicles
(3) Remove the bulb from the socket.
INSTALLATION—XJ VEHICLES
(1) Install a replacement bulb in the socket.
(2) Install the bulb and socket in the lamp housing.
(3) Position the lamp housing in the opening at the rear of the vehicle.
(4) Install the lamp housing screws. Tighten the screws securely.
REMOVAL—YJ VEHICLES
(1) Remove the lens retaining screws from the tail lamp housing (Fig. 25).
(2) Separate the lens from the tail lamp housing.
(3) Remove the bulb from the lamp socket.
INSTALLATION—YJ VEHICLES
(1) Install a replacement bulb in the lamp socket.
(2) Position the lens on the lamp housing.
(3) Install the lens retaining screws. Tighten the screws securely.
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(1) Raise liftgate.
(2) Remove CHMSL access door (Fig. 28)
(3) Remove CHMSL lamp mounting screws.
(4) Remove CHMSL lamp assembly.
(5) Replace bulbs if necessary (Fig. 29).
To install, reverse removal procedure.
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Fig. 25 Back-up/Rear Turn Signal/Tail Lamp Bulb
Replacement—YJ Vehicles
LICENSE PLATE LAMP
REMOVAL—XJ VEHICLES
(1) Remove screws and the license plate lamp visor from the liftgate (Fig. 26).
Fig. 27 Center High Mounted Stop Lamp (CHMSL)
Assembly
Fig. 26 License Plate Lamp Visor
(2) Remove the bulb from the lamp socket.
INSTALLATION—XJ VEHICLES
(1) Install a replacement bulb in the lamp socket.
(2) Position the license plate lamp visor on the liftgate and install screws. Tighten the screws securely.
CENTER HIGH MOUNTED STOP LAMP
(CHMSL)—XJ
The CHMSL is mounted at the top of the rear window and has two bulbs (Fig. 27).
Fig. 28 Removing CHMSL Access Door
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LAMPS 8L - 11
(2) Remove CHMSL lamp housing (Fig. 32)
(5) Replace bulbs if necessary.
To install, reverse removal procedure.
Fig. 29 Replacing CHMSL Bulb
CENTER HIGH MOUNTED STOP LAMP (CHMSL)—YJ
The CHMSL is mounted on top of a bracket that attaches to the spare tire carrier (Fig. 30).
(1) Remove the CHMSL lens (Fig. 31).
Fig. 31 Removing CHMSL Access Door
Fig. 30 Center High Mounted Stop Lamp (CHMSL) Bracket Assembly
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Fig. 32 Replacing CHMSL Bulb
FOG LAMP SERVICE INFORMATION
Fog lamps can be operated ONLY when the headlamps are on LOW beam. If the headlamps are switched to HIGH beam, the fog lamps will not operate.
Also, the fog lamps ON display on the switch will:
• be illuminated when the headlamps are switched to LOW beam; and
• be extinguished when the headlamps are switched to HIGH beam.
FOG LAMP TROUBLE DIAGNOSIS
ONE FOG LAMP INOPERATIVE
(1) Place the headlamp switch in the full ON position, the dimmer switch in the LOW beam position and the fog lamp switch in the ON position.
(2) Disconnect the applicable fog lamp wire harness connector (Fig. 33).
(3) Measure the resistance between the lamp connector terminals. The ohmmeter should indicate zero ohms. If not OK, replace the bulb.
(4) Measure the resistance between the wire harness connector ground terminal and vehicle body ground. The ohmmeter should indicate zero ohms. If not OK, repair the open circuit in the wire harness to vehicle body ground.
(5) Measure the voltage between the wire harness connector voltage supply terminal and body ground.
The voltmeter should indicate battery voltage. If not
OK, repair the open circuit in the wire harness that leads to the source of battery voltage.
BOTH FOG LAMPS INOPERATIVE
(1) Place headlamp switch in the full ON position.
Fig. 33 Fog Lamp & Wire Harness Connector—XJ
Vehicles
The dimmer switch in the LOW beam position. The fog lamp switch in the ON position.
(2) Measure the voltage between the fog lamp switch wire harness connector terminal B and vehicle body ground. The voltmeter should indicate battery voltage. If not OK, repair the open circuit in the wire harness that leads to the headlamp dimmer switch circuit.
(3) Measure the voltage between the fog lamp switch connector terminal C and vehicle body ground. The voltmeter should indicate battery voltage. If not OK, replace the fog lamp switch.
(4) Measure the voltage between the fog lamp relay connector terminal 1 and vehicle body ground.
The voltmeter should indicate battery voltage. If not
OK, repair the open circuit in the wire harness that leads to the power distribution center/PDC.
(5) Measure the voltage between the fog lamp relay connector terminal 5 and vehicle body ground.
The voltmeter should indicate battery voltage. If not
OK, repair the open circuit in the wire harness that leads to the fog lamp switch.
(6) Measure the voltage between the fog lamp relay connector terminal 2 and vehicle body ground.
The voltmeter should indicate battery voltage. If not
OK, repair the open circuit in the wire harness that leads to vehicle body ground.
(7) Measure the voltage between the fog lamp relay connector terminal 4 and vehicle body ground.
The voltmeter should indicate battery voltage. If not
OK, replace the relay.
FOG LAMP BEAM ADJUSTMENT
Use an ‘‘aiming’’ screen for fog lamp beam aim adjustment.
PREPARATION
Prior to adjustment, the following preparation is required.
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LAMPS 8L - 13
(1) Position the vehicle in dark area with a level floor and with a screen (wall) that has a white surface.
(2) Mark a reference line on the floor 7.62 meters
(25 feet) away from and parallel to the ‘‘aiming’’ screen/wall.
(3) Position vehicle with the fog lamps located directly above the 7.62-meters (25-feet) reference line.
(4) Equalize all the tire pressures.
(5) Rock the vehicle from side to side to stabilize the springs and shock absorbers.
(6) Refer to Figure 34. Use tape to attach a vehicle centerline on the screen/wall. Ensure that it is aligned with and represents the centerline of the vehicle.
FOG LAMP BULB/ELEMENT REPLACEMENT
REMOVAL
(1) For YJ vehicles, remove the screws that attach the stone shield and the reflector to the lamp housing. Remove the stone shield and reflector from the lamp housing (Fig. 35).
Fig. 35 Fog Lamp—YJ Vehicles
(2) For XJ vehicles, remove the screws that attach the bezel and lens to the lamp housing. Remove the bezel and the lens from the lamp housing (Fig. 36).
Fig. 34 Fog Lamp Beam Pattern
(7) Measure the distance between the vehicle fog lamp centers. Divide this distance by two. Measure the one/half distance outward from each side of the vehicle centerline. Use tape to attach the right and left fog lamp vertical centerline on the screen/wall.
(8) Measure the distance from the center of each fog lamp to the floor.
(9) Measure the lamp-to-floor distance upward from the floor at each lamp vertical centerline. Use tape to attach the lamp horizontal centerline on the screen/wall.
BEAM ADJUSTMENT
(1) Loosen the fog lamp attaching hardware at the support bracket.
(2) Place the headlamp and fog lamp switches in the ON position.
(3) Ensure that the headlamp dimmer switch is in the LOW beam position.
(4) Adjust the fog lamp beams according to the following guidelines:
• a properly adjusted fog lamp (up/down adjustment) will project a beam pattern on the screen similar to the pattern depicted in Figure 28; and
• each fog lamp should be centered (left/right adjustment) on the screen left/right vertical center line.
(5) Tighten the fog lamp support bracket hardware.
Fig. 36 Fog Lamp—XJ Vehicles
(3) Remove the bulb/element holder from the lens/ reflector.
(4) Remove the bulb/element from the holder.
REMOVAL
CAUTION: Always handle replacement quartz bulbs/ elements with a clean cloth. DO NOT handle quartz bulbs/elements with bare hands.
(1) Use a clean cloth to install a replacement bulb holder.
(2) Install the bulb holder in the lens/reflector.
8L - 14 LAMPS
(3) For XJ vehicles, position the bezel and the lens on the lamp housing. Install the screws that attach the bezel and lens to the lamp housing. Tighten the screws securely.
(4) For YJ vehicles, position the stone shield and reflector on the lamp housing. Install the screws that attach the stone shield and the reflector to the lamp housing. Tighten the screws securely.
FOG LAMP SWITCH REPLACEMENT
REMOVAL—XJ VEHICLES
The fog lamp switch is located on the instrument panel at the left of the steering column.
(1) Remove instrument panel bezel attaching screws and remove the bezel (Fig. 37).
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Fig. 38 Instrument Panel Shroud—YJ Vehicles
(3) Move the I/P shroud toward the steering wheel.
(4) Apply upward force to the I/P shroud and downward force to the indicator panel. This will release the indicator panel holding tabs (Fig. 39).
Fig. 37 Instrument Panel Bezel—XJ Vehicles
(2) Remove the fog lamp switch cover.
(3) Disconnect the wire harness connector from the switch.
(4) Squeeze the tabs on the side of the switch and remove the switch from the instrument panel cavity.
INSTALLATION—XJ VEHICLES
(1) Squeeze the tabs on the side of the fog lamp switch and insert the switch in the instrument panel cavity.
(2) Connect the wire harness connector to the switch.
(3) Install the fog lamp switch cover.
(4) Position the bezel on the instrument panel and install the attaching screws. Tighten the screws securely.
REMOVAL—YJ VEHICLES
The fog lamp switch is located on the instrument panel at the right of the steering column. The fog lamp circuit relay is located below the left headlamp.
(1) Disconnect the battery negative cable.
(2) Remove the I/P shroud retaining screws (Fig.
36).
Fig. 39 Indicator Panel Holding Tabs—YJ Vehicles
(5) Remove the shroud from the instrument panel.
(6) Remove the fog lamp switch retaining screws.
(7) Disconnect the wire harness connector from the fog lamp switch.
(8) Remove the fog lamp switch from the instrument panel cavity.
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LAMPS 8L - 15
INSTALLATION—YJ VEHICLES
(1) Position the fog lamp switch in the instrument panel cavity and connect the wire harness connector to the switch.
(2) Install the fog lamp switch retaining screws.
Tighten the screws securely.
(3) Position the I/P shroud under the steering column.
(4) Slide the indicator panel holding tabs into the shroud notches.
(5) Place the assembled I/P shroud over the indicator lamp foam gasket.
The foam gasket located on the back side of the indicator panel overlay is fragile. If it is either torn or distorted, replace it.
(6) Install and tighten the indicator panel retaining screws.
(7) Install the remaining shroud screws. Tighten the screws securely.
(8) Connect the battery negative cable.
FOG LAMP REPLACEMENT
REMOVAL—XJ VEHICLES
(1) Disconnect the fog lamp wire harness connector
(Fig. 40).
Fig. 41 Fog Lamp—XJ Vehicles
(2) Remove the fog lamp nut(s), washers(s) and bolt(s) from the support bracket.
Fig. 40 Fog Lamp Wire Harness Connector—XJ
Vehicles
(2) Remove the retaining nut and washer from each side of the support bracket and remove the fog lamp from the support bracket (Fig. 41).
INSTALLATION—XJ VEHICLES
(1) Position the fog lamp in the support bracket and install the washer and nut at each side of the bracket. Tighten the nuts securely.
(2) Connect the fog lamp wire harness connector.
REMOVAL—YJ VEHICLES
(1) Disconnect the fog lamp wire harness connector.
Fig. 42 Round-Shaped Fog Lamp
(3) Remove the fog lamp from the support bracket.
INSTALLATION—YJ VEHICLES
(1) Position the fog lamp on the support bracket.
(2) Install the fog lamp bolt(s), washer(s) and nut(s) in the support bracket.
(3) Connect the fog lamp wire harness connector.
SENTINEL HEADLAMP DELAY MODULE—XJ
VEHICLES
SERVICE INFORMATION
The Headlamp Module delays the de-activation of the headlamps for 45 6 15 seconds after the ignition
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Fig. 43 Rectangular-Shaped Fog Lamp
Fig. 44 Fog Lamp—YJ Renegade switch is turned OFF. The driver engages the module by turning the ignition switch OFF, then turning the headlamps OFF.
The headlamp delay module is located behind the
I/P next to the headlamp switch.
HEADLAMP DELAY MODULE REPLACEMENT—XJ
VEHICLES
The headlamp delay module is attached to the inside of the instrument panel to the right of the headlamp switch.
REMOVAL
(1) Remove the lower instrument panel.
(2) Remove the screw that attaches the module to the inside of the instrument panel.
(3) Disconnect the wire harness connector and remove the module from the instrument panel.
INSTALLATION
(1) Position the module inside the I/P and connect the wire harness connector to the module.
(2) Install the screw that attaches the module to the inside of the instrument panel.
(3) Remove the lower instrument panel.
HEADLAMP DELAY FUNCTION TROUBLE
DIAGNOSIS—XJ VEHICLES
DELAY FUNCTION INOPERATIVE
(1) Remove, inspect and test the HD LP DLY fuse.
Replace if defective.
(2) Remove the delay module from the I/P. Do not disconnect the wire harness connector. Turn the ignition switch to the RUN position. Place the headlamp switch in headlamps ON position. Turn the ignition to the OFF position for a resistance test.
(3) Measure the resistance from the delay module terminal 4 to vehicle body ground. The ohmmeter should indicate zero ohms. If not, repair the open circuit in the wire harness to vehicle body ground.
(4) Measure the voltage between the delay module terminal 8 and vehicle body ground. The voltmeter should indicate battery voltage. If not, repair the open circuit in the wire harness to the instrument cluster indicator connector terminal 14.
(5) Measure the voltage between the delay module terminal 6 and vehicle body ground. The voltmeter should indicate battery voltage. If not, repair the open circuit in the wire harness to the headlamp switch.
(6) Measure the voltage between the delay module terminal 2 and vehicle body ground. The voltmeter should indicate battery voltage. If not, repair the open circuit in the wire harness to the fuse.
DAYTIME RUNNING LIGHTS (CANADA ONLY)
SERVICE INFORMATION
The Daytime Running Lights (Headlamps) System is installed on ve