PSI-0A-gen info 1.6L.indd - Southeastern Equipment &amp

PSI-0A-gen info 1.6L.indd - Southeastern Equipment &amp

Go to Table of Contents

Original Issue

Dated January 2004

Publication Number 16LECSS

1.6L

EMISSION CERTIFIED

INDUSTRIAL ENGINE

EMISSION CONTROL SYSTEM

SERVICE MANUAL

TABLE OF CONTENTS

Section 0A - General Information

Section 0B – Maintenance

Section 1A1 – LPG Fuel System Operation

Section 1A2 – Gasoline Fuel System Operation

Section 1B1 – LPG System Diagnosis

Section 1B2 – Gasoline System Diagnosis

Section 1B4 – System Symptom Diagnosis

Section 1C2 – Engine Control System Electrical

Section 1C4 – Diagnostic Trouble Codes

Section 1E1 – Fuel System R&R

No part of this publication may be reproduced without the written permission of Power Solutions, Inc. At the time of publication, all of the information included in this publication is accurate to the best of our knowledge. Power Solutions, Inc., cannot be responsible for information that has changed after this book was published.

1.6 liter Emission Certified GM Engine General Information 0A-1

SECTION 0A

GENERAL INFORMATION

Fuel System Cautions ................................................................0A-2

Terms and Definitions ....................................................0A-3 - 0A-6

Go to Table of Contents

0A-2 General Information

FUEL SYSTEMS CAUTIONS

CAUTION: Do not smoke, carry lighted tobacco, or use a lighted flame of any type when working on or near any fuel related component. Highly flammable air-fuel mixtures may be present and can be ignited causing personal injury.

CAUTION: Do not allow propane to contact the skin. Propane is stored in the fuel tank as a liquid.

When propane contacts the atmosphere, it immediately expands into a gas, resulting in refrigeration that can cause severe burns.

CAUTION: Do not allow propane to accumulate in areas below ground level such as in a service pit or underground ventilation systems. Propane is heavier than air and can displace oxygen, creating a dangerous condition.

It is important to note that this manual contains various

Warnings, Cautions and Notes that must be carefully observed in order to reduce the risk of personal injury during service or repair. Improper service or repair may damage the engine or render it unsafe or fail to make the engine emissions compliant. It is also important to warn of all hazardous consequences that might result from careless treatment of the engine. Failure to observe these items could influence terms of the warranty.

!

WARNING

Failure to heed could result in death, injury or property damage.

!

CAUTION

Less severe than WARNING, but has the potential to cause injury or damage. Also used to notify of situations that could lead to eventual failure, injury or damage.

IMPORTANT: Denotes situations which could influence safety or proper performance of the vehicle or component.

NOTICE: Significant item of information.

To reduce the chance of personal injury and/or property damage, the following instructions must be carefully observed.

1.6 liter Emission Certified GM Engine

• Proper service and repair are important to the safety of the service technician and the safe reliable operation of all engines. The service procedures recommended and described in this service manual are effective methods of performing service and repair. Some of these procedures require the use of tools specially designed for the purpose.

• If part replacement is necessary, the replacement part must be of the same part number or equivalent part. Do not use a replacement part of lesser quality. In the case of replacement parts for the emission control system use only genuine

OEM replacement parts.

• Before using a replacement part, service procedure, or a tool which is not recommended by the engine manufacturer, it must first be determined that neither personal safety nor the safe operation of the engine will be jeopardized by the replacement part, service procedure or the tool selected.

• Special service tools shown in this service manaual that have tool product numbers beginning with “J” or “BT” are available for world wide distribution from: o Kent-Moore Tools o 28635 Mound Road o Warren, MI. 48092 o 1-800-345-2233

• Special Tools which are required to service the

LPG fuel system are listed below o Hand held diagnostic scanner o ITK-1 Fuel pressure test kit

The tools are available from:

IMPCO Engine System Division

7100 East 15 Mile Road

Sterling ‘Heights, MI. 48312

1-586-276-4333

ENGLISH AND METRIC FASTENERS

!

CAUTION

Late model engines use a combination of English and Metric fasteners. The components affected are the starter motor, engine mounts, and flywheel housing mounting. Other components may also have a combination of fasteners, always verify that the proper fasteners are used whenever removing or replacing any components.

1.6 liter Emission Certified GM Engine General Information 0A-3

Terms and Definitions

Air Valve Vacuum (AVV): The vacuum signal taken from below the air valve assembly and above the throttle butterfly.

ADP: Adaptive Digital Processor.

Air/Fuel Ratio: The amount of air and fuel in the air fuel mixture, which enters the engine, shown in a ratio.

Analog Voltmeter: A meter that uses a needle to point to a value on a scale of numbers usually of the low impedance type; used to measure voltage and resistance.

Aromatics: Pertaining to or containing the six-carbon ring characteristic of the benzene series. Found in many crude oils.

Backfire: Combustion of the air/fuel mixture in the intake or exhaust manifolds. A backfire can occur if the intake or exhaust valves are open when there is a mis-timed ignition spark.

Benzene: An aromatic (C6H6). Sometimes blended with gasoline to improve antiknock value. Benzene is toxic and suspected of causing cancer.

Bi-Fueled: A vehicle equipped to run on two fuels at the same time such as a fumigated diesel.

Blow-By: Gases formed by the combustion of fuel and air, which ordinarily should exert pressure only against the piston crown and first compression ring. When rings do not seal, these gases (blowby) escape down the side of the piston into the crankcase.

BTU: British Thermal Unit. A measurement of the amount of heat required to raise the temperature of 1lb. of water 1 degree F.

Butane: An odorless, colorless gas, C4H10 found in natural gas and petroleum. One of the five LP gases.

CAFE: Corporate Average Fuel Economy.

CARB: California Air Resources Board.

Carbon Monoxide (CO): A chemical compound of a highly toxic gas that is both odorless and colorless.

Carburetor: An apparatus for supplying an internal-combustion engine a mixture of vaporized fuel and air.

Cathode Ray Tube: A vacuum tube in which cathode rays usually in the form of a slender beam are projected on a fluorescent screen and produce a luminous spot.

Circuit: A path of conductors through which electricity flows before it returns to its source.

Closed Loop Operation: Applies to systems utilizing an oxygen sensor. In this mode of operation, the system uses oxygen sensor information to determine air/fuel ratio. Adjustments are made accordingly and checked by comparing the new oxygen sensor to previous signals. No stored information is used.

CNG: Compressed Natural Gas.

CKP: Crankshaft Position Sensor

CMP: Camshaft Position Sensor

Conductor: A material, normally metallic, that permits easy passage of electricity.

Contaminants: Impurities or foreign material present in fuel.

Control Module: One of several names for a solid state microcomputer which monitors engine conditions and controls certain engine functions; i.e. air/fuel ratio, injection and ignition time, etc.

Converter: A LPG fuel system component containing varying stages of fuel pressure regulation combined with a vaporizer.

Cryogen: A refrigerant used to obtain very low temperatures.

Current: The directed flow of electrons through a conductor. Measured in amps.

Dedicated Fuel System: A motor fuel system designed to operate on only one fuel type.

Diaphragm: A thin, flexible membrane that separates two chambers. When the pressure in one chamber is lower than in the other chamber, the diaphragm will move toward the side with the low pressure.

Diaphragm Port: The external port located at the fuel inlet assembly and connected to the vacuum chamber above the air valve diaphragm.

Digital Volt/Ohm Meter (DVOM): A meter that uses a numerical display in place of a gauge and is usually of the high impedance type.

DTC: Diagnostic Trouble Code

DST: Diagnostic Scan Tool.

DVOM: Digital volt/ohmmeter.

ECT: Engine Coolant Temperature.

0A-4 General Information 1.6 liter Emission Certified GM Engine

ECM : Electronic Control module

EFI: Electronic Fuel Injection. A fuel injection system, which uses a microcomputer to determine and control the amount of fuel, required by, and injected into, a particular engine.

EGR: Exhaust gas recirculation.

EPA: Environmental Protection Agency: A regulating agency of the Federal government which, among other duties, establishes and enforces automotive emissions standards.

Ethanol: Grain alcohol (C2H5OH), generally produced by fermenting starch or sugar crops.

Evaporative Emissions Controls: An automotive emission control system designed to reduce hydrocarbon emissions by trapping evaporated fuel vapors from the fuel system.

Excess Flow Valve: A check valve that is caused to close by the fuel when the flow exceeds a predetermined rate.

FTV: Fuel Trim Valve.

FFV: Flexible Fuel Vehicle.

Firing Line: The portion of an oscilloscope pattern that represents the total amount of voltage being expended through the secondary circuit.

FMVSS: Federal Motor Vehicle Safety Standards.

FPP: Foot Pedal Position Sensor

Fuel Injector:, a spring loaded, electromagnetic valve which delivers fuel into the intake manifold, in response to electrical from the control module.

Fuel Lock: A solenoid-controlled valve located in the fuel line to stop the flow when the engine stops or the ignition switch is off.

Gasohol: 10 percent ethanol, 90 percent gasoline. Often referred to as E-10.

Gasoline: A motor vehicle fuel that is a complex blend of hydrocarbons and additives. Typical octane level is 89.

Greenhouse Effect: A scientific theory that suggests that excessive levels of carbon dioxide from the burning of fossil fuels is causing the atmosphere to trap heat and cause global warming.

HD 10: A fuel of not less than 80% liquid volume propane and not more than 10% liquid volume propylene.

HD 5: A fuel of not less than 90% liquid volume propane and not more than 5% liquid volume propylene.

HDV: Heavy Duty Vehicle.

Hg: Chemical symbol for mercury. Used in reference to vacuum (in. of Hg).

Hydrocarbon: A chemical compound made up of hydrogen and carbon (HC). A major pollution emission of the internal combustion engine. Gasoline and almost all other fuels are hydrocarbons.

Hydrostatic Relief Valve: A pressure relief device installed in the liquid propane hose on a propane fuel system.

IAT: Intake Air Temperature

Ideal Mixture: The air/fuel ratio at which the best compromise of engine performance to exhaust emissions is obtained.

Typically 14.7:1.

Ignition Reserve: The difference between available voltage and the required voltage.

ILEV: Inherently Low Emission Vehicle.

IMPCO: Imperial Machine Products Company. IMPCO Technologies, Inc. A manufacturer of both LPG and Gasoline fuel systems.

Impedance: A form of opposition of AC current flow (resistance) measured in ohms.

Insulation: A nonconductive material used to cover wires in electrical circuits to prevent the leakage of electricity and to protect the wire from corrosion.

Intercept: An electrical term for a type of splice where the original circuit is interrupted and redirected through another circuit.

ITK: IMPCO Test Kit

Knock: Sound produced when an engine’s air/fuel mixture is ignited by something other than the spark plug, such as a hot spot in the combustion chamber. Can be caused by a fuel with an octane rating that is too low or maladjusted ignition timing. Also called detonation or ping.

Lambda Sensor: A feedback device, usually located in the exhaust manifold, which detects the amount of oxygen present in exhaust gases in relation to the surrounding atmosphere.

1.6 liter Emission Certified GM Engine

LDV: Light Duty Vehicle.

Lean Mixture: An air to fuel ratio above the stoichiometric ratio; too much air.

General Information 0A-5

LEV: Low Emission Vehicle.

Limp-in or Limp-home: This term is used to describe the drivability characteristics of a failed computer system

Liquified Petroleum Gas (LPG): A fuel commonly known as propane consisting mostly of propane (C3H8), derived from the liquid components of natural gas stripped out before the gas enters the pipeline, and the lightest hydrocarbons produced during petroleum refining. Octane level is 107.

LPG: Liquified Petroleum Gas.

M85: A blend of gasoline and methanol consisting of 85% methanol and 15% gasoline.

Measurements of Pressure: 1 PSI=2.06 Hg (mercury) = 27.72” H2O (water column). At sea level atmospheric pressure is 29.92”

Hg.

Methanol: Known as wood alcohol (CH3OH), a light, volatile, flammable alcohol commonly made from natural gas.

Misfire: Failure of the air/fuel mixture to ignite during the power stroke.

Mixer: Fuel introduction device that does not include a throttle plate.

MPFI: Multi-Point Fuel injection. A fuel injection system that uses one injector per cylinder mounted on the engine to spray fuel near the intake valve area of combustion chamber.

MTBE: Methyl Tertiary Butyl Ether. Oxygenate add to gasoline to reduce harmful emissions and to improve the octane rating.

Multi-fuel System: A motor fuel system designed to operate on two different fuels, such as LPG and gasoline.

Natural Gas: A gas formed naturally from buried organic material, composed of a mixture of hydrocarbons, with methane

(CH4) being the dominant component.

NGV: Natural Gas Vehicle.

Nox: See Oxides of Nitrogen.

Octane Rating: The measurement of the antiknock value of a motor fuel.

OEM: Original Equipment Manufacturer, the vehicle manufacturer.

Open-Loop: An operational mode during which control module memory information is used to determine air/fuel ratio, injection timing, etc., as opposed to actual oxygen sensor input.

Orifice: A port or passage with a calibrated opening designed to control or limit the amount of flow through it.

Oscilloscope: An instrument that converts voltage and frequency readings into traces on a-cathode ray tube (also see Cathode

Ray Tube).

Oxides of Nitrogen: Chemical compounds of nitrogen bonded to various amounts of oxygen (Nox). A chief smog forming-agent.

Oxygen Sensor: An automotive fuel system that produces a signal in accordance with the oxygen content of the exhaust gas.

(See Lambda Sensor).

Oxygenate: MTBE, ethanol and methanol. Oxygenates are added to gasoline to increase the oxygen content and therefore reduce exhaust emissions.

Ozone: A radical oxygen module (O3) that is found in the upper atmosphere and filters out ultraviolet radiation from the sun.

Ground level ozone is formed by Nox, during the formation of photochemical smog.

Particulates: Microscopic pieces of solid or liquid substances such as lead and carbon that are discharged into the atmosphere by internal combustion engines.

Positive Crankcase Ventilation (PCV): An automotive emission control system designed to reduce hydrocarbon emissions by routing crankcase fumes into the intake manifold rather than to the atmosphere.

Pressure Differential: The differential between atmospheric pressure and intake manifold (referred to as vacuum) pressure.

Pressure Regulator: A device to control the pressure of fuel delivered to the fuel injector(s).

Primary Circuit: The low-voltage or input side of the ignition coil.

Propane: An odorless, colorless gas, C3H8, found in natural gas and petroleum.

PTV: Pressure Trim Valve

Reactivity: Refers to the tendency of an HC in the presence of Nox and sunlight to cause a smog-forming reaction. The lighter the HC, the lower reactivity tends to be.

Regulator: An assembly used to reduce and control the pressure of a liquid or vapor.

0A-6 General Information 1.6 liter Emission Certified GM Engine

Resistance: The opposition to the flow of current in an electrical circuit. Measured in ohms.

Rest Pressure: Fuel pressure maintained within the system after engine shutdown.

Rich Mixture: An air to fuel ratio below the stoichiometric ratio; too much fuel.

SAE: Society of Automotive Engineers.

Secondary Circuit: The high-voltage output side of the ignition coil.

SEFI or SFI: Sequential Electronic Fuel Injection or Sequential Fuel Injection.

Sensors: Devices that provide the control module with engine information as needed to properly control engine function.

Spark Line: The portion of an oscilloscope pattern that represents the time during which the air/fuel mixture is being burned in the combustion chamber.

Splice: An electrical term for the joining of two or more conductors at a single point.

Stoichiometric Ratio: An ideal fuel/air ratio for combustion in which all of the fuel and most of the oxygen will be burned.

Sulfur Oxides: Chemical compounds where sulfur is bonded to varying numbers of oxygens, produced by the combustion of gasoline or any other fuel that contains sulfur. As sulfur oxides decompose in the atmosphere, they combine with water to form sulfuric acid.

System Pressure: The fuel pressure maintained in the system during normal engine operation.

Tap: An electrical term for a type of splice where the original circuit is not interrupted.

TBI: Throttle Body Injection. Any of several injection systems that have the fuel injector(s) mounted in a centrally located throttle body.

Throttle Body: Controls engine RPM by adjusting the engine manifold vacuum to the mixer. Consists of housing shaft, throttle liner and butterfly valve.

TLEV: Transitional Low Emission Vehicle.

TMAP: Combined Air Inlet and Manifold Pressure Sensor.

Toluene: A liquid aromatic hydrocarbon C7H8.

TPS: Throttle Position Sensor.

ULEV: Ultra Low Emission Vehicle.

Vaporization: A process in which liquid changes states into gas.

Venturi Air Valve Vacuum (VAVV): An amplified air valve vacuum signal coming from the venturi area of the mixer, directly exposed to airflow before the addition of vaporized LPG.

Volt/Ohmmeter (VOM): A combination meter used to measure voltage and resistance in an electrical circuit. Available in both analog and digital types. May be referred to as AVOM and DVOM.

Voltage: The electrical pressure that causes current to flow in a circuit. Measured in volts.

Voltage Drop: A lowering of the voltage in a circuit when resistance or electrical load is added.

Xylene: C6H4 (CH3)2. Any of three toxic flammable oily isomeric aromatic hydrocarbons that are dimethyl homologues of benzene and are usually obtained from petroleum or natural gas distillates.

ZEV: Zero Emission Vehicle.

1.6 liter Emission Certified GM Engine

SECTION OB

MAINTENANCE

Maintenance ..................................................................0B-2

Checking Coolant Level .................................................0B-3

Checking/Changing Oil .................................................0B-4

Fuel System Inspection & Maintenance ........................0B-5

Checking/Draining Oil in Low Pressure Regulator .........0B-6

Exhaust/Catalytic Converter Maintenance .....................0B-7

Fuel Pressure Regulator Maintenance/Inspection .........0B-8

Maintenance Chart ........................................................0B-9

Filter Chart ..................................................................0B-10

Maintenance–OB-1

Go to Table of Contents

OB-2–Maintenance

MAINTENANCE

The maintenance of the engine and its related components is critical to the life of the engine and optimum performance during its useful life. All engines require a certain amount of maintenance. The suggested maintenance requirements are contained in this section. Industrial engines operate in various environments from extremely dusty environments, to hot and cold temperature environments and clean environments. The recommended schedule is a recommended guide line for the owner and servicing agency to follow, however certain environmental operating conditions may require more frequent inspection and maintenance. In addition the owner may have installed additional equipment to the equipment which may also increase the requirements for service on certain components. Therefore the owner and servicing agent should review the operating condition of the equipment and determine if more frequent inspections and maintenance cycles maybe required.

!

WARNING

When performing maintenance on the engine, shut off the engine and disconnect the battery negative cable to avoid injury or damage to the engine.

The engine installed in this equipment may use one or both accessory drive belt configurations. The drive belt may be incorporated to drive the water pump, alternator and addition pumps or devices. It is important to note, the drive belt is an integral part of the cooling and charging system and should be inspected at a minimum according to the maintenance schedule in this section and in extremely hot and dirty environments more often.

When inspecting the belts check for:

• Cracks,

• Chunking of the belt,

• Splits

• Material hanging loose from the belt

• Glazing, hardening

If any of these conditions exist the belt should be replaced with an OEM replacement belt.

V-BELT SYSTEMS

Check the belt tension by pressing down on the midway point of the longest stretch between two pulleys. The belt should not depress beyond 13mm (1/2 inch). If the depression is more than allowable adjust the tension. Do not over tighten the tension of the belt. Over tightening may cause overload on the bearings and pulleys of the drive belt components.

SERPENTINE BELT SYSTEM

1.6 liter Emission Certified GM Engine

Serpentine belts utilize a spring-loaded tensioner which keeps the belt properly adjusted. Serpentine belts should be checked according to the maintenance schedule in this section.

IMPORTANT:

The engine manufacturer does not recommend the use of “belt dressing” or “anti slipping agents” on either belt

configuration.

COOLING SYSTEM

!

WARNING

Alcohol or Methanol base antifreeze or plain water are not recommended for use in the cooling system at anytime.

It is important to remember that the cooling system of this engine be maintained properly to insure the longevity of the engine. Maintenance of the cooling system is critical to not only the engine but the fuel system as well. Because the LPG vaporizer is connected into the cooling system low coolant levels and restricted or plugged radiator cores can impact the performance of the fuel system. Therefore proper maintenance of the cooling system should include removing dust, dirt and debris from the radiator core on regular intervals. To properly maintain the cooling system follow the recommend maintenance schedule in this section.

Cooling system inspections should be performed as prescribed when inspecting the cooling system check for the following:

• Plugged or restricted radiator core clean with compressed air, blow dust and debris from the core and the fan shroud

• Check the radiator cap to insure proper sealing if damage replace

• Check for coolant leaks at the radiator tank seams and inlet joints repair or replace as necessary

• Check for leaks at the radiator hose connections, tighten hose clamps if necessary

• Check Radiator hoses for swelling, separation, cracks deterioration in the hoses, or hardening, if any of these conditions exist the hose should be replaced with the OEM replacement parts

• Check coolant level if low add with 50/50 mixture,

Do not add plain water

• Replace coolant per the recommended schedule at the end of this section

CHECKING THE COOLANT LEVEL

1. Check coolant level in coolant recovery tank. Add

1.6 liter Emission Certified GM Engine specified coolant as required.

!

WARNING

Do not remove the cooling system pressure cap when the engine is hot.

Allow the engine to cool and then remove the cap slowly allowing pressure to vent. Hot coolant under pressure may discharge violently

IMPORTANT:

The engine manufacturer and the fuel system supplier do not recommend the use of “stop leak” additives to repair leaks in the cooling system. If leaks are present the radiator should be removed and repaired.

If the radiator requires repair insure that the radiator core repairs did not result in a significant reduction in the cooling capacity of the radiator.

The engine manufacturer recommends the cooling system be filled with a 50/50 mixture of ethelyene glychol anitfreeze and water.

This GM industrial engine can utilize any type of permanent antifreeze or any brand antifreeze solution that meets GM Specification 1825M or 1899M which will not damage aluminum parts.

ENGINE ELECTRICAL SYSTEM

MAINTENANCE

The engine electrical system incorporates computers to control certain functions of the equipment. The electrical system connections and ground circuits require good connections.

Follow the recommended maintenance schedule in this section to maintain optimum performance. When inspecting the electrical system check the following:

• Check battery connection clean and insure that connectors are tight.

• Check battery for cracks or damage to the case replace if necessary.

• Check Positive and Negative cables for corrosion, rubbing, chaffing and insure tight connections at both ends.

• Check engine wire harness for rubbing, chaffing, pinching, and cracks or breaks in the wiring.

• Check engine harness connectors, check to insure fitted and locked by pushing the connector together then pull on the connector halves to insure they are locked.

• Check ignition coil wire for hardening, cracking,

Maintenance–OB-3 arcing, chaffing, separation, split boot covers and proper fit.

• Check spark plug wires for hardening, cracking, chaffing, separation, split boot covers and proper fit.

• Replace spark plugs at the required intervals per the recommended maintenance schedule

• Check to insure all electrical components are securely mounted and retained to the engine or chassis.

• Check to insure any additional electrical devices installed by the owner are properly installed in the system.

• Check the MIL, charging, and oil pressure lights for operation by starting the engine and checking that the light illuminates for the prescribe period of time before turning out.

ENGINE CRANKCASE OIL

OIL RECOMMENDATION

Prior to changing the oil, select oil based on the prevailing daytime temperature in the area in which the equipment will be operated. The chart in figure 1 is a guide to selecting the proper crankcase oil.

IMPORTANT: Oils containing “solid” additives, nondetergent oils, or low quality oils are not recommended by the engine manufacturer.

Figure 1 Engine Oil Viscosity Recommendation

USE OF SUPPLEMENTAL ADDITIVES

Use of the oils recommended by the engine manufacturer already contains a balanced additive treatment. The uses of supplemental additives which are added to the engine oil by the customer are not necessary and may be harmful.

The engine manufacturer, fuels system suppliers and engine distributors do not review, approve or recommend such

OB-4–Maintenance products.

SYNTHETIC OILS

Synthetic oils have been available for use in industrial engines for a relatively long period of time. Synthetic oils may offer advantages in cold temperature pumpability and high temperature oxidations resistance. However, synthetic oils have not proven to provide operational or economic benefits over conventional petroleum-based oils in industrial engines.

Their use does not permit the extension of oil change intervals.

CHECKING/FILLING ENGINE OIL LEVEL

IMPORTANT; Care must be taken when checking engine oil level. Oil level must be maintained between the “ADD” mark and the “FULL” mark on the dipstick. To ensure that you are not getting a false reading, make sure the following steps are taken before checking the oil level.

1. Stop engine if in use

2. Allow sufficient time (approximately 5 minutes) for the oil to drain back into the oil pan

3. Remove the dipstick. Wipe with a clean cloth or paper towel and reinstall. Push the dipstick all the way into the dipstick tube.

4. Remove the dipstick and note the oil level.

5. Oil level must be between the “FULL” and “ADD” marks.

Figure 2 Engine Oil Dip stick (Typical)

6. If the oil level is below the “ADD” mark, proceed to Step

7 and 8, and reinstall the dipstick into the dipstick tube.

7. Remove the oil filler cap from the valve rocker arm cover

8. Add the required amount of oil to bring the level up to but not over the “FULL” mark on the dipstick

9. Reinstall the oil filler cap to the valve rocker arm cover and wipe any excess oil clean.\

CHANGING THE ENGINE OIL

IMPORTANT: When changing the oil, always change the

oil filter.

1.6 liter Emission Certified GM Engine

!

CAUTION

Overfilled crankcase (oil level being to high) can cause an oil leak, a flucuation or drop in the oil pressure and rocker arm “clatter” on engines. The overfill condition results in the engine crankshaft splashing and agitating the oil, causing it to foam (become aereated). The aereated oil causes the hydraulic lifters to “bleed down”. This results in rocker arm clatter and loss of engine performance due to valves not opening properly.

1. Start the engine and run until it reaches normal operating temperature.

IMPORTANT: Change oil when engine is warm from operation as it flows more freely, carrying away more impurities.

2. Stop engine.

IMPORTANT: Engine oil will be hot. Use protective gloves to prevent burns. Engine oil contains chemicals which may be harmful to your health avoid skin contact.

3. Remove drain plug and allow the oil to drain.

4. Remove and discard oil filter and it sealing ring.

5. Coat sealing ring on the new filter with clean engine oil, wipe the sealing surface on the filter mounting surface to remove any dust, dirt or debris. Tighten filter securely

(follow filter manufacturers instructions). Do not overtighten.

6. Check sealing ring on drain plug for any damage, replace if necessary, wipe plug with clean rag, wipe pan sealing surface with clean rag and re-install plug into the pan.

Tighten to specification.

7. Fill crankcase with oil.

8. Start engine and check for oil leaks.

9. Dispose of oil and filter in a safe manner.

FUEL SYSTEM INSPECTION AND

MAINTENANCE

1.6 liter Emission Certified GM Engine

PROPANE FUEL SYSTEM

The Propane fuel system installed on this industrial engine has been designed to meet the emission standard applicable for this equipment for 2004 model year. To ensure compliance to these standards follow the recommended maintenance schedule contained in this section.

INSPECTION AND MAINTENANCE OF THE

FUEL STORAGE CYLINDER

The fuel storage cylinder should be inspected daily or at the beginning of each operational shift for any leaks, external damage, adequate fuel supply and to insure the manual service valve is open. Fuel storage cylinders should always be securely mounted, inspect the securing straps or retaining devices for damage insure that all locking devices are closed and locked. Check to insure that the fuel storage cylinder is positioned with the locating pin in the tank collar on all horizontally mounted cylinders this will insure the proper function of the cylinder relief valve.

When refueling or exchanging the fuel cylinder check the quick fill valve for thread damage. Insure the o-ring is in place, check the o-ring for cracking, chunking or separation, replace if damaged before filling. Check the service line quick coupler for any thread damage. Insure the o-ring is in place, check the o-ring for cracking, hardening, chunking or separation. Replace if damaged.

IMPORTANT: When refueling the fuel cylinder, wipe clean both the female and male connection with a clean rag prior to filling. This will prevent dust, dirt and debris from being introduced to the fuel cylinder and prolong the life of the fuel filter.

INSPECTION AND REPLACEMENT OF THE

FUEL FILTER

The Propane system on this emission certified engine utilizes an in-line replaceable fuel filter element. This element should be replaced, at the intervals specified in the recommended maintenance schedule. When inspecting the fuel filter check the following:

• Check for leaks at the inlet and outlet fittings, using a soapy solution or an electronic leak detector, if leaks are detected make repairs

• Check to make sure filter is securely mounted.

• Check filter housing for external damage or distortion, if damaged replace fuel filter

Maintenance–OB-5

To replace the filter use the following steps:

1. Move the equipment to a well ventilated area and insure all external ignition sources are not present.

2. Start the engine.

3. With the engine running close the manual valve.

4. When the engine runs out of fuel turn OFF the key when the engine stops and disconnect the battery negative cable.

IMPORTANT: A small amount of fuel may still be present in the fuel line, use gloves to prevent burns, wear proper eye protection. If liquid fuels continues to flow from the connections when loosened check to make sure the manual valve is fully closed.

5. Slowly loosen the inlet fitting and disconnect.

6. Slowly loosen the outlet fitting and disconnect.

7. Remove the filter housing form the equipment.

8. Check for contamination.

9. Tap the opening of the filter on a clean cloth.

10. Check for debris.

11. Check canister for proper mounting direction.

12. Reinstall the filter housing to the equipment.

13. Tighten the inlet and outlet fittings to specification.

14. Open the manual valve.

IMPORTANT: The fuel cylinder manual valve contains an

“Excess Flow Check Valve” open the manual valve slowly to prevent activating the “Excess Flow Check Valve”.

15. Check for leaks at the inlet and outlet fittings, and the filter housing end connection using a soapy solution or an electronic leak detector, if leaks are detected make repairs.

LOW PRESSURE REGULATOR

MAINTENANCE AND INSPECTION

IMPORTANT: The Low Pressure Regulator (LPR) components have been specifically designed and calibrated to meet the fuel system requirements of the emission certified engine. The regulator should not be disassembled

or rebuilt. If the LPR fails to operate or develops a leak

the LPR should be replaced with the OEM recommended replacement parts.

When inspecting the regulator check for the following items:

• Check for any fuel leaks at the inlet and outlet fittings.

• Check for any fuel leaks in the regulator body.

• Check the inlet and outlet fittings of the coolant supply lines for water leaks.

• Check the coolant supply lines for hardening, cracking, chaffing or splits. If any of these conditions exist replace coolant lines.

• Check coolant supply hose clamp connections, ensure they are tight.

• Check the to ensure the Pressure Trim Valve

OB-6–Maintenance

(PTV) mounting bolts are secure.

• Check PTV for external damage.

• Check PTV electrical connection to ensure the connector is seated and locked.

• Check to ensure the regulator is securely mounted.

CHECKING/DRAINING OIL BUILD-UP IN

THE LOW PRESSURE REGULATOR

During the course of normal operation oil or “heavy ends” may build inside the secondary chamber of the Low Pressure

Regulator (LPR). These oil and heavy ends may be a result of poor fuel quality, contamination of the fuel supply chain, or regional variation of the fuel make up. If the build up of oil becomes significant this can affect the performance of the secondary diaphragm response. The Recommended

Maintenance Schedule found in this section recommends that the oil be drained periodically.

IMPORTANT: Draining the regulator when the engine is warm will help the oils to flow freely from the regulator.

To drain the LPR use the following steps:

1. Move the equipment to a well ventilated area and ensure no external ignition sources are present.

2. Start the engine.

3. With the engine running close the manual valve.

4. When the engine runs out of fuel turn OFF the key when the engine stops and disconnect the battery negative cable.

IMPORTANT: A small amount of fuel may still be present in the fuel line, use gloves to prevent burns, wear proper eye protection. If liquid fuels continues to flow from the connections when loosened check to make sure the manual valve is fully closed.

5. Slowly loosen the inlet fitting and disconnect.

6. Loosen the hose clamp at the outlet hose fitting and remove the hose.

7. Remove and retain the locking pin in the outlet fitting and remove the outlet fitting from the LPR

8. Disconnect PTV connection and disconnect the vacuum hose.

9. Remove the two LPR mounting bolts and retain.

10. Place a small receptacle in the engine compartment.

11. Rotate the LPR to 90° so that the outlet fitting is pointing down into the receptacle and drain the LPR.

12. Inspect the secondary chamber for any large dried particles and remove.

13. Remove the receptacle and reinstall the LPR with the two retaining bolts and tighten to specifications.

14. Reinstall the outlet fitting and secure with the previously removed locking pin.

15. Reconnect the PTV electrical connection push connector until lock “Click”, pull on the connector to ensure it is locked, connect the vacuum line.

1.6 liter Emission Certified GM Engine

16. Reconnect the outlet hose and secure the hose clamp.

17. Reinstall the fuel inlet line and tighten connection to specification.

18. Slowly open the manual service valve.

IMPORTANT: The fuel cylinder manual valve contains an

“Excess Flow Check Valve” open the manual valve slowly to prevent activating the “Excess Flow Check Valve”.

19. Check for leaks at the inlet and outlet fittings using a soapy solution or an electronic leak detector, if leaks are detected make repairs. Check coolant line connections to ensure no leaks are present.

20. Start engine recheck for leaks at the regulator.

21. Dispose of any drained material in safe and proper manner.

AIR FUEL MIXER/THROTTLE

CONTROL DEVICE MAINTENANCE

AND INSPECTION

IMPORTANT: The Air Fuel Mixer components have been specifically designed and calibrated to meet the fuel system requirements of the emission certified engine. The mixer

should not be disassembled or rebuilt. If the mixer fails

to operate or develops a leak the mixer should be replaced with the OEM recommended replacement parts.

When inspecting the mixer check for the following items:

• Check for any fuel leaks at the inlet fitting.

• Check the fuel inlet hose for cracking, splitting or chaffing, replace if any of these condition exist.

• Check to ensure the mixer is securely mounted.

• Check air inlet hose connection and insure clamp is tight, check inlet hose for cracking, splitting or chaffing, replace if any of these condition exist.

• Check air cleaner element according to the

Recommended Maintenance Schedule found in this section.

• Check fuel line to Throttle body mounted Fuel

Trim Valve (FTV) for cracking, splitting or chaffing, replace if any of these condition exist.

• Check Throttle body return action to ensure throttle shaft is not sticking repair if necessary.

• Check FTV electrical connection to ensure connector is fully seated and locked.

• Check for leaks at the throttle body and intake manifold.

• Check Throttle cable for damage, rubbing, and kinking and free movement repair if necessary.

1.6 liter Emission Certified GM Engine

EXHAUST SYSTEM AND CATALYTIC

CONVERTER INSPECTION AND

MAINTENANCE

IMPORTANT: The exhaust system on this emission certified engine contains an Exhaust Gas Oxygen Sensor

(EGO) which provides feed back to the ECM on the amount of oxygen present in the exhaust stream after combustion. The measurement of oxygen in the exhaust stream is measured in voltage and sent to the ECM.

The ECM then makes corrections to the fuel air ratio to ensure the proper fuel charge and optimum catalytic performance. Therefore it is important that the exhaust connections remain secured and air tight.

IMPORTANT: The EGO sensor is sensitive to silicone or silicone based products. Do not use silicone sprays or hoses which are assembled using silicone lubricants.

Silicone contamination can cause severe damage to the

EGO.

When inspecting the Exhaust system check the following:

• Check the exhaust manifold at the cylinder head for leaks and that all retain bolts and shields (if used) are in place.

• Check the manifold to exhaust pipe fasteners to ensure they are tight and that there are no exhaust leaks repair if necessary.

• Check EGO electrical connector to ensure connector is seated and locked, check wires to ensure there is no cracking, splits chaffing or

“burn through” repair if necessary.

• Check any exhaust pipe extension connector for leaks tighten if necessary

• Visually inspect converter to insure muffler is securely mounted and tail pipe is properly aimed.

• Check for any leaks at the inlet and outlet of the converter

GASOLINE FUEL SYSTEM

FUEL TANK MAINTENANCE AND

INSPECTION

The gasoline fuel tank on most forklifts is integrated into the chassis of the forklift. Gasoline is stored as a liquid in the fuel tank and is drawn from the fuel tank through a pick-up tube by an externally mounted 12 volt electric fuel pump.

When inspecting the fuel tank check the following;

• Check for leaks in the tank.

• Check the fill cap sealing ring for cracks, chunking, separation replace if any of these conditions exist.

Maintenance–OB-7

• Check the fill cap for cracks check threads for burrs and distortion ensure cap is tight.

• Check outlet hose fitting and connection ensure tight seal.

• Check fuel return line connection and fittings for leaks.

• Check fuel return line for cracking, chaffing, separation replace if any of these conditions exist.

GASOLINE FUEL FILTER INSPECTION AND

REPLACEMENT

The gasoline fuel system incorporates an inlet replaceable fuel filter to remove dirt, debris and contaminants which may have been introduced into the fuel tank. Replace the filter as prescribed in the Recommended Maintenance Schedule found in this section.

When inspecting the gasoline fuel filter check the following;

• Check for leaks at the inlet and outlet connections of the filter.

• Check to ensure the gasoline fuel filter is securely mounted.

• Check for any damage to the filter.

To replace the Gasoline fuel filter use the following steps:

1. Move the forklift to a well ventilated area and insure all external ignition sources are not present.

2. Place a drain receptacle under the forklift to capture any fuel which may drain from the lines.

3. Shut OFF the engine.

4. Disconnect the fuel inlet fitting.

5. Disconnect the fuel outlet fitting.

6. Remove the gasoline fuel filter from the mounting bracket

7. Discard the filter in a safe and proper manner

8. Reinstall the fuel filter into the securing bracket and tighten retaining fastener

9. Ensure the gasoline fuel filter is mounted in the proper direction arrow should be in the direction of flow.

10. Reconnect the inlet and outlet fittings and tighten to specification.

11. Remove drain pan and discard any drained gasoline in a safe and proper manner

12. Start engine and check for leaks, repair if necessary.

FUEL PUMP MAINTENANCE AND

INSPECTION

The fuel pump is specifically design to supply the correct fuel pressure to the injector pressure regulator. During normal engine operation excessive fuel from the fuel rails is bypassed back to the fuel tank. If the fuel pump fails to operate replace with the OEM replacement part only, substitute must supply to

OB-8–Maintenance much fuel and cause excessive pressure in the fuel and damage to the fuel system.

When inspecting the fuel pump check the following;

• Check for leaks at the fuel pump.

• Check the inlet and outlet fittings for leaks.

• Check the electrical connection to ensure the connector is fully seated and locked.

• Check the fuel pump wire harness to ensure the harness is secure in its retaining device and that the wire harness is not chaffing or routed improperly.

• Check to make sure the fuel pump is securely mounted to the chassis.

FUEL PRESSURE REGULATOR

MAINTENANCE AND INSPECTION

The gasoline fuel injection system utilizes a single stage pressure regulator to maintain a constant fuel supply to the fuel rails and injectors. The regulator is specifically designed and calibrated to meet the emission requirements of the certified engine. If the regulator fails to operate it should only be replaced with the OEM replacement part.

When inspecting the fuel pressure regulator check the following;

Check for leaks at the inlet and outlet fitting of the regulator.

Check for external leaks at the regulator

Check to ensure the regulator is securely mounted

Check the fuel inlet and outlet supply lines for cracks, chaffing or separations replace if any of these conditions exist

FUEL RAILS AND INJECTORS

The fuel delivery system of the gasoline injection system utilizes two fuel rails to supply fuel to the injectors. The gasoline fuel injectors supply the specific amount of fuel for the combustion cycle. The ECU sends a signal to the injector to open for the calibrated time for fuel delivery to the intake port. The injectors utilized for the emissions certified engines are specifically calibrated if an injector fails to operate it should only be replaced with the OEM replacement parts.

When inspecting the fuel rails and injector check the following:

• Check the fuel inlet line connections for leaks

• Check the fuel return line connections for leaks

• Check the fuel rail for leaks or external damage

• Check to ensure the fuel rail is securely mounted

• Check the fuel rail to injector connections for

1.6 liter Emission Certified GM Engine leaks

• Check the base of the injector for leaks

• Check the injector wire connections to ensure sure they are fully seated and locked

• Check the fuel pressure sender electrical connection to ensure they are fully seated and locked

• Check the fuel pressure sender connection at the fuel rail for leaks

FUEL ADDITIVES

The engine manufacturer does not recommend the use of

Injector cleaners or fuel additives which clean fuel system parts. Use of such additives are unnecessary if the fuel system filter is change as required and clean refueling practices are practiced. Avoid storing fuel in containers which are not specifically designed to store gasoline. Avoid storing gasoline in dusty and dirty environments doing so will further prevent contamination of the fuel system.

1.6 liter Emission Certified GM Engine Maintenance–OB-9

Install

Date

Daily 250 500 750 1000 1250 1500 1750 2000

General Maintenance Section

Visual check for leaks

Check engine oil level

Check coolant level

Change engine oil and filter

Check Fuel system for leaks

Inspect Accessory Drive belts

Inspect electrical system

Inspect all vacuum lines and fitting

Inspect all fuel lines and fitting

Engine Coolant Section

Check coolant level

Clean debris from radiator core

Change coolant

Inspect coolant hoses for cracks, swelling or deterioration

Engine Ignition System

Inspect Battery case for damage

Inspect battery cables

Check all electrical connectors

Check ignition timing and adjust

Replace spark plugs

Check spark plug wires

Fuel System Maintenance

Replace fuel filter

Inspect lock off for leaks

Ensure lock if closing

Test LPG/Gas regulator pressure

Inspect gasoline fuel lines for leaks

Inspect LPR for oil build up

Inspect LPR for coolant leaks

Check air induction system for leaks

Check manifold for vacuum leaks

Check FCVS electrical connection

Check throttle shaft for sticking

Check injector & rails for leaks

Inspect air cleaner

Replace filter element

Engine Exhaust System

Inspect exhaust manifold for leaks

Inspect exhaust piping for leaks

Inspect catalyst inlet and outlet

Check EGO sensor connector

X

X

X

X

X

X

Every 100 hours or 60 days of operation

Prior to any service or maintenance activity

Every 100 hours or 60 days of operation

X

X

X

X

X

X

X

X

X

X

Annually or every 2000 hours

Annually or every 2000 hours

Every 200 hours, or every 100 hours in dusty environment

Annually, or Bi-annually in dusty environments

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

The maintenance schedule represents manufacturers recommended maintenance intervals to maintain proper engine/equipment function. Specific state and federal regulations may require equipment operators to conduct comprehensive engine/equipment inspections at more periodic intervals than those specified above. This maintenance schedule has no regulatory value and should not be considered representative of any state or federal engine/equipment maintenance requirement.

OB-10–Maintenance 1.6 liter Emission Certified GM Engine

Filter Part Number Chart

Oil Filter 01458

Fuel Filter - Gasoline 32500916

Fuel Filter - LPG RK-FL219

1.6 liter Emission Certified GM Engine Fuel System Operation 1A1-1

SECTION 1A1

LPG FUEL SYSTEM OPERATION

LPG System Scehmatic ............................................................1A1-2

Descritpion of Operation of System Components ....1A1-3-1A1-8

Go to Table of Contents

1A1-2 Fuel System Operation 1.6 liter Emission Certified GM Engine

Tank Pressure

Regulated Pressure

Intake Air

Air/Fuel Mixture

Exhaust Gas

IMPCO SPECTRUM LPG FUEL SYSTEM

Fuel Cylinder

Fuel Filter

Mil

Light

Electric

Lockoff

PTV

Low

Pressure

Regulator

Engine Control Unit

Air Cleaner Mixer

TMAP

Speed control motor

Throttle Body

FTV

TPS

ENGINE

H20

Sensors

Distributor

(Timing)

Magnetic

Pick up (RPM) o2

Catalytic Muffler

Figure 1 Typical Fuel System Schematic

1.6 liter Emission Certified GM Engine

DESCRIPTION AND OPERATION OF

THE FUEL SYSTEMS

PROPANE FUEL SYSTEM

The primary components of the propane fuel system are the fuel storage tank, low pressure regulator (LPR), fuel mixer module with throttle control device, electric fuel lock-off solenoid, engine control module (ECM) fuel trim valve (FTV) pressure trim valve (PTV) and Three Way Catalytic (TWC) converter. The system operates at pressures which range from

355.60 mm (14.0 inches) of water column up to 21.5 BAR (312 psi). Figure 1 Typical Fuel System Schematic

Fuel System Operation 1A1-3

SERVICE LINE

!

CAUTION

The bulkhead assembly should never be removed and a service line run throught the sheet metal.

Propane flows from the fuel tank to the electric lock via the service line. The service line is connected to the tank utilizing a quick coupler. The other end of the service line is connected to a “bulkhead connector” mounted on the equipment sheet metal. This bulkhead connector allows for a safe means of passing through the equipments engine compartment sheet metal and into the engine compartment. If a bulkhead connector is used a pressure relief device is mounted in the service line or the connector itself to prevent over pressurization of the service line. The service line is made of high pressure hose with special material or possibly tubing which is friendly to the LPG fuel and must always be replaced with an OEM supplied part.

LPG FUEL TANK

Propane is stored in the fuel tank as a liquid. The approximate pressure of the fuel in the tank is 16.5 bar (240 psi) when the tank is full at an ambient temperature of 27° C

(81°F). The boiling point, (temperature at which the liquid fuel becomes vapor) is approximately -40° C (-40° F). When the fuel changes from liquid to vapor the fuel expands and creates pressure inside the tank. When the tank service valve is opened the pressure inside the tank forces the liquid fuel out though the pick up tube located near the bottom of the fuel cylinder. Because the Propane is stored under pressure the tank is equipped with a safety valves which are normally set at 25.8 bar (375 psi) to prevent tank rupture due to overpressurization of the cylinder. The service valve is mounted in the end of the cylinder controls the flow of fuel from the tank. By turning the handle to its “open” position, fuel flows out of the tank and into the service line. The service valve is also equipped with a safety feature called an “excess flow check valve”. This feature reduces the flow from the service valve in the event of a rupture of the fuel line or any down stream component.

1. Liquid Outage valve w/quick disconnect coupling

2. Filler Valve

3. Pressure Relief Valve

11. Vapor Withdrawal Tube

(when applicable)

12. 80% Limitor Tube

13. Fuel Level Float

4. Liquid Outage Fill Check Valve 14. Liquid Withdrawal Tube

5. Fuel Gauge

FUEL FILTER

Propane fuel like all other motor fuels is subject to contamination from outside sources. Refueling of the equipments tank and removal of the tank from the equipment can inadvertently introduce dirt and other foreign matter into the fuel system. It is therefore necessary to filter the fuel prior to entering the fuel system components down stream of the tank.

The fuel filter is integrated into the electric lock off assembly. Maintenance of the filter is critical to proper operation of the fuel system and should be replaced as defined in the

Recommended Maintenance Schedule. In severe operating condition more frequent replacement of the filter may be necessary.

ELECTRIC LOCK OFF

The Electric Lock Off device is an integrated assembly. The electric lock assembly is a 12 volt normally closed valve. The solenoid is mounted to the valve body. When energized the solenoid opens the valve and allows the Propane fuel to flow through the device. The valve opens during cranking and run cycles of the engine. The lock off supply voltage is controlled by the engine control module (ECM).

Figure 2 Typical Propane Cylinder

1A1-4 Fuel System Operation 1.6 liter Emission Certified GM Engine

LOW PRESSURE REGUALTOR (LPR)

!

CAUTION

Figure 3 Integrated Fuel Lock Off and Filter Assembly

The LPR is an emission control device. Components inside the regulator are specifically calibrated to meet the engine emissions requirements and should never be disassembled or rebuilt. If the LPR fails to operate, replace with an OEM replacement part.

volt normally closed solenoid. The function of this solenoid is to regulate a specific amount of venture vacuum to the atmospheric side of the secondary diaphragm. By introducing vacuum to the top side of the secondary diaphragm during regulator operation the amount of fuel being delivered to the mixer can be “trimmed” or reduced to allow for correction to the air fuel ratio for closed loop fuel control. The solenoid receives a reference signal from the ECM which causes the solenoid to be pulsed fast or slow depending on the amount of fuel to be trimmed.

The LPR is a combination vaporizer, pressure regulating device. The LPR is a negative pressure two stage regulator that is normally closed when the engine is not running. When the engine is cranking or running a partial vacuum is created in the fuel line which connects the regulator to the mixer. This partial vacuum opens the regulator permitting fuel to flow to the mixer.

Propane fuel enters the primary port of the LPR and passes through the primary jet and into the primary/exchanger chamber. As the propane passes through the heat exchanger the fuel expands and creates pressure inside the chamber. The pressure rises as the fuel expands when the pressure rises above 10.34 kpa (1.5 psi), sufficient pressure is exerted on the primary diaphragm to cause the diaphragm plate to pivot and press against the primary valve pin thus closing off the flow of fuel. This action causes the flow of fuel into the regulator to be regulated. When the engine is cranking, sufficient vacuum will be introduce into the secondary chamber from the mixer drawing the secondary diaphragm down onto the spring loaded lever and opening the secondary valve allowing vaporized fuel to pass to the mixer. Increased vacuum in the secondary chamber increases the downward action on the secondary lever causing it to open wider allowing more fuel to flow to the mixer.

The regulator utilized on this emission certified engine is equipped with a unique Pressure Trim Valve (PTV) which is directly mounted to the regulator. This solenoid is a 12

Figure 4 Low pressure regulator

AIR FUEL MIXER

The air valve mixer is an air-fuel metering device and is completely self-contained. The mixer is an air valve design, utilizing a relatively constant pressure drop to draw fuel into the mixer from cranking to full load. The mixer is mounted in the air stream ahead of the throttle control device.

1.6 liter Emission Certified GM Engine

When the engine begins to crank it draws in air with the air valve covering the inlet, negative pressure begins to build.

This negative pressure signal is communicated to the top of the air valve chamber through 4 vacuum ports in the air valve assembly. A pressure/force imbalance begins to build across the air valve diaphragm between the air valve vacuum chamber and the atmospheric pressure below the diaphragm. The air valve vacuum spring is calibrated to generate from 101.6 mm (4.0 inches) of water column at start to as high as 355.60 mm (14.0 inches) of water column at full throttle. The vacuum being created is referred to as Air Valve Vacuum (AVV).

As the air valve vacuum reaches 101.6mm (4.0 inches) of water column, the air valve begins to lift against the air valve spring. The amount of AVV generated is a direct result of the throttle position. At low engine speed the air valve vacuum is low and the air valve position is low thus creating a small venturi for the fuel to flow. As the engine speed increase the

AVV increases and the air valve is lifted higher thus creating a much larger venturi. This air valve vacuum is communicated from the mixer venture to the LPR secondary chamber via the low pressure fuel supply hose. As the AVV increases in the secondary chamber the secondary diaphragm is drawn further down forcing the secondary valve lever to open wider.

!

CAUTION

The air/fuel mixer is an emission control device. Components inside the mixer are specifically calibrated to meet the engines emissions requirements and should never be disassembled or rebuilt. If the mixer fails to operate replace with an OEM replacement part.

The mixer is equipped with a low speed mixture adjustment which is retained in a tamper proof housing. The mixer has been preset at the factory and should not require any adjustment. In the event that the idle adjustment should need to be adjusted refer to the Fuel System Repair section of this manual.

Fuel System Operation 1A1-5

Figure 5 Air Fuel Mixer

Figure 6 Pressure Trim Valve and Fuel Trim Valve

1A1-6 Fuel System Operation

THROTTLE CONTROL DEVICE

Drive By Wire

Engine speed control is maintained by the amount of pressure applied to the foot pedal located in the engine compartment.

In a Drive By Wire (DBW) application there is no direct connection between the operator pedal and the throttle shaft.

Speed and load control are determined by the ECM. Defaults programmed into the ECM software and throttle position sensors allow the ECM to maintain safe operating control over the engine.

In a drive by wire application the Electronic Throttle Control device or “throttle body assembly” is connected to the intake manifold of the engine. The electronic throttle control device utilizes an electric motor connected to the throttle shaft. In addition a Foot Pedal Position sensor (FPP) located in the operator’s compartment. When the engine is running electrical signals are sent from the foot pedal position sensor to the engine ECM when the operator depresses or release the foot pedal. The ECM then sends an electrical signal to the motor on the electronic throttle control to increase or decrease the angle of the throttle blade thus increasing or decreasing the air flow to the engine.

The electronic throttle control device also incorporates two internal Throttle Position Sensors (TPS) which provide output signals to the ECM as to the location of the throttle shaft and blade. The TPS information is used by the ECM to correct for speed and load control as well as emission control.

Also mounted on Electronic throttle body assembly is the

Fuel Trim Valve (FTV). The FTV is a 12 volt normally closed solenoid valve. During closed loop operation the ECM may send a reference signal to the FTV to open or close to allow more or less fuel to be introduced below the throttle blade to correct the air fuel mixture for proper emission control.

1.6 liter Emission Certified GM Engine

Figure 7 Throttle control device “Drive by Wire throttle body assembly”

THREE WAY CATALYTIC MUFFLER

The emission certified engine has been designed and calibrated to meet the emission standards in effect for 2004. To help meet the emission requirements the vehicle has been equipped with a Three Way Catalytic (TWC) muffler. The catalyst muffler is a three way catalyst, sound damping and spark arresting unit. Besides controlling the noise created from the combustion process, and preventing sparks from escaping from the exhaust system the most important function is treating the exhaust gases which are created from the combustion process. The three-way catalyst consists of a honeycomb coated with a mixture of platinum, palladium, and rhodium.

The hot gases flow through the catalyst sections where an oxidation and reduction reactions take place. These chemical reactions reduce the amount of CO, HC and NOX in the engines exhaust. The Exhaust gas then flows through the outlet.

1.6 liter Emission Certified GM Engine Fuel System Operation 1A1-7

The controller also performs diagnostic functions on the fuel system and notifies the operator of malfunctions by turning on a Malfunction Indicator Light (MIL) mounted in the dash.

Malfunctions in the system are identified by a Diagnostic

Code number. In addition to notifying the operator of the malfunction in the system the controller also stores the information about the malfunction in its memory. A technician can than utilize a computerized diagnostic tool to retrieve the stored diagnostic code and by using the diagnostic charts in this manual determine the cause of the malfunction. In the event a technician does not have the computerized diagnostic tool the MIL light can be used to identify the diagnostic code.

By following specific steps the technician can activate the

“blink” feature and count the number of blinks to determine the diagnostic code number to locate the fault in the system.

Figure 8 Three way catalytic converter

HEATED EXHAUST GAS OXYGEN SENSOR

!

The Heated Exhaust Gas Oxygen

Sensor (HEGO) is an emissions control component. If the HEGO fails to operate, replace only with an OEM replacement part. The HEGO sensor is sensitive to silicone and silicone based products and can become contaminated. Avoid using silicone sealers or hoses treated with silicone lubricant in the air stream or fuel supply lines.

CAUTION

ENGINE CONTROL MODULE

To obtain maximum effect from the catalyst and accurate control of the air fuel ratio the emission certified engine is equipped with an onboard computer or Engine Control

Module (ECM). The ECM is a 32 bit controller which receives in-put data from sensors fitted to the engine and fuel system and then out-puts various signals to control engine operation.

One specific function of the controller is to maintain “closed loop fuel control”. Closed loop fuel control is accomplished when the exhaust gas oxygen sensor (HEGO) mounted in the exhaust system sends a voltage signal to the controller. The controller then calculates any correction that may need to be made to the air fuel ratio. The controller then out-puts signals to PTV or the FTV or both mounted in the fuel system to change the amount of fuel being delivered from the regulator or mixer or to the engine.

The Heated Exhaust Gas Oxygen Sensor (HEGO) is mounted in the exhaust system downstream of the engine. The HEGO is used to measure the amount of oxygen present in the exhaust stream and communicate that to the ECM via an electrical signal. The amount of oxygen present in the exhaust

Figure 9 LPG Engine Control Module (ECM)

1A1-8 Fuel System Operation stream indicates whether the fuel air ratio is to rich or to lean.

If the HEGO sensor signal indicates that the exhaust stream is to rich the ECM will decrease or lean the fuel mixture during engine operation, if the mixture is to lean the ECM will richen the mixture. The ECM continuously monitors the

HEGO sensor output if a rich or lean condition is present for an extended period of time and the ECM cannot correct the condition the ECM will set a diagnostic code and turn on the

MIL light in the dash.

1.6 liter Emission Certified GM Engine

Figure 10 Heated Exhaust Gas Oxygen Sensor

(HEGO)

Figure 11 Propane Closed Loop Control Schematic

1.6 liter Emission Certified GM Engine Fuel System Operation 1A2-1

SECTION 1A2

GASOLINE FUEL SYSTEM OPERATION

Gasoline System Scehmatic ...................................................1A2-2

Descritpion of Operation of System Components ...1A2-3-1A2-6

Go to Table of Contents

1A2-2 Fuel System Operation 1.6 liter Emission Certified GM Engine

IMPCO 1.6 LITER MPFI FUEL SYSTEM

AIR FUEL MIXTURE

FRESH AIR

EXHAUST GASES

GASOLINE RETURN

GASOLINE FUEL PRESSURE

GASOLINE FUEL PUMP PRESSURE

Fuel Tank

Gasoline

Fuel Pump

Mil

Light

Fuel Filter

Pressure

Regulator

Engine Control

Module

Air Cleaner

Air

Induction

TMAP

Speed control motor

Throttle Body TPS

Manifold

Injector

ENGINE

(MPFI) System

H20

Sensors

Distributor

(Timing)

Magnetic

Pick up (RPM)

O2

Catalytic

Muffler

Figure 1 Gasoline Multi-Port Fuel Injection System

1.6 liter Emission Certified GM Engine

THROTTLE CONTROL DEVICE

Drive By Wire

Engine speed control is maintained by the amount of pressure applied to the foot pedal located in the engine compartment.

In a Drive By Wire (DBW) application there is no direct connection between the operator pedal and the throttle shaft.

Speed and load control are determined by the ECM. Defaults programmed into the ECM software and throttle position sensors allow the ECM to maintain safe operating control over the engine .

In a drive by wire application the Electronic Throttle Control device or “throttle body assembly” is connected to the intake manifold of the engine. The electronic throttle control device utilizes an electric motor connected to the throttle shaft. In addition a Foot Pedal Position sensor (FPP) is located in the operator’s compartment. When the engine is running electrical signals are sent from the foot pedal position sensor to the engine ECM when the operator depresses or release the foot pedal. The ECM then sends an electrical signal to the motor on the electronic throttle control to increase or decrease the angle of the throttle blade thus increasing or decreasing the air flow to the engine.

The electronic throttle control device also incorporates two internal Throttle Position Sensors (TPS) which provide output signals to the ECM as to the location of the throttle shaft and blade. The TPS information is used by the ECM to correct for speed and load control as well as emission control.

Fuel System Operation 1A2-3

THREE WAY CATALYTIC MUFFLER

The emission certified engine has been designed and calibrated to meet the emission standards in effect for 2004. To help meet the emission requirements the vehicle has been equipped with a Three Way Catalytic muffler. The catalyst muffler is a three way catalyst, sound damping and spark arresting unit. Besides controlling the noise created from the combustion process, and preventing sparks from escaping from the exhaust system the most important function is treating the exhaust gases which are created from the combustion process.

The three-way catalyst consists of a honeycomb coated with a mixture of platinum, palladium, and rhodium. The hot gases flow through the catalyst sections where an oxidation and reduction reactions take place. These chemical reactions reduce the amount of CO, HC and NOX in the engines exhaust. The

Exhaust gas then flows through the outlet

Figure 3 Throttle control device “Drive by Wire throttle body assembly”

Figure 4 Three way catalytic converter

ENGINE CONTROL UNIT

To obtain maximum effect from the catalyst and accurate control of the air fuel ratio the emission certified engine is equipped with an onboard computer or Engine Control Unit

(ECM). The ECM is a 32 bit controller which receives in-put data from sensors fitted to the engine and fuel system and then out-puts various signals to control engine operation.

One specific function of the controller is to maintain “closed loop fuel control”. Closed loop fuel control is accomplished when the exhaust gas oxygen sensor (EGO) mounted in the exhaust system sends a voltage signal to the controller. The controller then calculates any correction that may need to be made to the air fuel ratio. The controller then out-puts signals to PTV or the FTV or both mounted in the fuel system to change the amount of fuel being delivered from the regulator

1A2-4 Fuel System Operation 1.6 liter Emission Certified GM Engine or mixer or to the engine.

Figure 5 Gasoline Engine Control Module (ECM)

The controller also performs diagnostic functions on the fuel system and notifies the operator of malfunctions by turning on a Malfunction Indicator Light (MIL) mounted in the dash.

Malfunctions in the system are identified by a Diagnostic

Code number. In addition to notifying the operator of the malfunction in the system the controller also stores the information about the malfunction in its memory. A technician can than utilize a computerized diagnostic tool to retrieve the stored diagnostic code and by using the diagnostic charts in this manual determine the cause of the malfunction. In the event a technician does not have the computerized diagnostic tool the MIL light can be used to identify the diagnostic code.

By following specific steps the technician can activate the

“blink” feature and count the number of blinks to determine the diagnostic code number to locate the fault in the system. haust stream and communicate that to the ECM via an electrical signal. The amount of oxygen present in the exhaust stream indicates whether the fuel air ratio is to rich or to lean.

If the HEGO sensor signal indicates that the exhaust stream is to rich the ECM will decrease or lean the fuel mixture by reducing the signals to the injectors during engine operation, if the mixture is to lean the ECM will richen the mixture or increase the pulse to the injectors. The ECM continuously monitors the HEGO sensor output if a rich or lean condition is present for an extended period of time and the ECM cannot correct the condition the ECM will set a diagnostic code and turn on the MIL light in the dash.

HEATED EXHAUST GAS OXYGEN SENSOR

!

CAUTION

The Heated Exhaust Gas Oxygen

Sensor (HEGO) is an emissions control component. If the HEGO fails to operate, replace only with an OEM replacement part. The HEGO sensor is sensitive to silicone and silicone based products and can become contaminated. Avoid using silicone sealers or hoses treated with silicone lubricant in the air stream or fuel supply lines.

The Heated Exhaust Gas Oxygen Sensor (HEGO) is mounted in the exhaust system downstream of the engine. The HEGO is used to measure the amount of oxygen present in the ex-

Figure 6 Exhaust Gas Oxygen Sensor (EGO)

1.6 liter Emission Certified GM Engine

GASOLINE MULTI POINT FUEL

INJECTION SYSTEM (MPFI)

The primary components of the Gasoline Multi Point Fuel

Injection (MPFI) fuel system are the gasoline fuel tank, electric fuel pump, fuel filter, fuel rails, fuel pressure regulator, fuel injector, O2 sensor, engine control module and three way catalytic muffler.

GASOLINE FUEL STORAGE TANK

The gasoline fuel storage tank location may very on equipment applications. The fuel tank may be integrated into the chassis frame or may be a stand alone vessel mounted on the equipment. For precise location for the equipment application refer to the OEMs vehicle manual.

Fuel System Operation 1A2-5 filter may be required if the equipment operates in a dusty or dirty environment.

FUEL RAIL AND PRESSURE REGULATOR

The fuel flows from the fuel filter to the fuel rails where the fuel is regulated. During engine operation the regulator maintains the proper amount of fuel pressure to the top of the injector. During lower RPM operation excess fuel at the top of the injector is bypassed and returned to the fuel tank for recirculation.

The Fuel pressure regulator has no adjustments and is integrated into the fuel rail assembly. The fuel rail also contains a Schrader valve which is utilized to test the regulated pressure of the fuel system.

GASOLINE FUEL PUMP

!

CAUTION

The fuel pump is an emissions control component. If the fuel pump fails to operate, replace only with an OEM replacement part. The fuel pump is calibrated to supply the correct amount of fuel to the injectors. Replacing the pump with anything other than the

OEM replacement could cause damage to the fuel system and or damage to the fuel tank.

The Gasoline is stored as a liquid in the fuel tank and in drawn into the fuel system by a 12 volt electric fuel pump.

Depending on the vehicle application the fuel pump may be mounted in the fuel tank or as a stand alone component. In either case the fuel pump will receive a signal from the ECM at Key On to prime the fuel system for approximately 2 seconds prior to start. Priming of the fuel system provides for a quicker start, when the engine begins to crank.

Figure 2 Gasoline Fuel Rail Assembly with injectors

FUEL FILTER

After the fuel is drawn into the fuel pump the fuel then flows through the gasoline fuel filter. The fuel filter will trap small particles as the fuel passes through the filter to remove debris and prevent injectors from becoming damaged. Maintenance of the fuel filter is required as indicated in the Recommended

Maintenance Schedule. A more frequent replacement of the

FUEL INJECTOR

The fuel supply is maintained on the top of the injector by the fuel pressure regulator. The injector is fed a “pulse” signal through the wire harness which causes the injector to open. During regular operating conditions the ECM controls the opening and duration of opening of the injector. During lower RPM operation the injector signals or “pulses” are less frequent then when the engine is operating at higher RPMs.

The certified engine has been calibrated to deliver the precise amount of fuel for optimum performance and emission control.

1A2-6 Fuel System Operation 1.6 liter Emission Certified GM Engine

"Output"

Injector pulse increases or decreases fuel delivery to the engine

ECM Calaculates the change and commands injector signal to increase or decrease

Figure 7 Gasoline Closed Loop Control Schematic

"Input"

Heated

Exhaust

Gas Oxygen

Sensor

(HEGO) to

ECM

1.6 liter Emission Certified GM Engine LPG Fuel System Diagnostics 1B1-1

SECTION 1B1

LPG SYSTEM DIAGNOSIS

LPG System Description and Diagnostic Aids .....................1B1-2

LPG Fuel System Diagnosis .......................................1B1-3-1B1-6

Fuel Control Diagnosis ...............................................1B1-7-1B1-10

Go to Table of Contents

1B1-2 LPG Fuel System Diagnostics

LPG FUEL SYSTEM DIAGNOSIS

1.6 liter Emission Certified GM Engine

DIAGNOSTIC AIDS

This procedure is intended to diagnose a vehicle operating on

LPG. If the vehicle will not continue to run on LPG, refer to

Hard Start for preliminary checks. Before proceeding with this procedure, verify that the vehicle has a sufficient quantity of fuel and that liquid fuel is being delivered to the LPR.

Also, ensure that the manual shut off valve on the LPG tank is fully opened and that the excess flow valve has not been activated.

Tools Required:

• 7/16 Open end wrench (for test port plugs)

• Straight Blade screw driver

• DVOM (GM J 39200, Fluke 88 or equivalent).

Duty Cycle Monitoring Tool

• IMPCO Fuel System Analyzer (FSA), or DVOM

(GM J 39200, Fluke 88 or equivalent).

Diagnostic Scan Tool

• IMPCO hand held PDA or equivalent.

Pressure Gauges

• Water Column Gauge / Manometer (GM 7333-6 or equivalent).

• 0-10 PSI Gauge

Fuel System Description

The Engine Control Module (ECM) receives information from various engine sensors in order to control the operation of the fuel control solenoid valves (FTV) and the low-pressure lock-off (LPL) solenoid. The LPL solenoids prevent fuel flow unless the engine is cranking or running. LPG is stored in the tank and delivered under pressure to the system as a liquid. During key on, the LPL receives a two (2) second prime pulse from the ECU which allows LPG to flow from the tank through fuel filter and fuel lines to the low pressure regulator

(LPR) at pressures up to 21.5 BAR (312 psi).

In the (LPR) the fuel is vaporized and the pressure reduced in two stages. The first stage reduces the pressure to approximately 20.68 kilopascals (3.0 psi). The second stage reduces the pressure to approximately negative 38.1 mm (1.5”) of water column.

The fuel is then drawn from the secondary chamber of the

LPR by the vacuum generated by air flowing through the mixer. This vacuum signal is also used to generate lift for the mixer air valve. This vacuum signal is most commonly referred to as air valve vacuum. In the mixer, the fuel mixes with the air entering the engine. This air/fuel mixture is then drawn into the engine for combustion.

Test Description

The numbers below refer to step numbers on the diagnostic table.

5. This step will determine if the PTV and FTV and fuel supply system are functioning properly. The vacuum on the secondary test port will be approximately –1.0 “ to

–2.0” w.c.

6. This step checks the base mechanical LPR output pressure by disabling all fuel control devices.

9. This step checks for proper air valve operation.

19. This determines if fuel is available from the fuel tank supply system.

1.6 liter Emission Certified GM Engine LPG Fuel System Diagnostics 1B1-3

LPG Fuel System Diagnosis

Step

1

2

Action

Were you referred to this procedure by a DTC diagnostic chart?

Perform the On Board Diagnostic (OBD) System

Check.

Value(s)

__

__

Yes

Go to Step 3

Go to the applicable DTC

Table

No

Go to Step 2

Go to Step 3

3

Are any DTCs present in the ECM?

Verify that the LPG fuel tank has a minimum of 1/4 tank of fuel, that the manual valve is open and the tank quick connect is fully engaged

__

__

Go to Step 4

4

Does the vehicle have fuel?

1. Connect a water column gauge or a manometer to the secondary test port of the low pressure regulator (LPR).

2. Start the engine and allow it to reach operating temperature.

__

5

Does the engine start and run?

With the engine idling, observe the pressure reading for the LPR secondary pressure.

-1.0” to

-2.0” w.c.

Go to Step 5 Go to Step 8

6

7

Does the fuel pressure fluctuate rhythmically

OUTSIDE the specified range?

1. Disconnect the PTV electrical connectors.

Note:

This action may cause a DTC to be set by the ECU

2. With the engine idling observe the pressure reading on the secondary test port.

Is the fuel pressure WITHIN the specified range?

1. Inspect the air intake stream between the mixer assembly and the throttle body for leaks.

2. Inspect the fuel hose connection between the

LPR and mixer assembly for damage or leakage.

3. Inspect the vacuum hoses to the FTV solenoid.

-1.0” to

-2.0” w.c.

__

Go to Step 25 Go to Step 6

Go to Fuel

Control System

Diagnosis

Go to Step 7

Was a problem found and corrected?

Go to Step 26 Go to Step 22

1B1-4 LPG Fuel System Diagnostics

8

1. Connect a water column gauge or a manometer to the secondary test port of the low pressure regulator (LPR).

2. Crank the engine and observe the pressure reading for the LPR secondary pressure.

9

Does the fuel pressure indicate a vacuum is present?

1. Remove Air induction hose to the mixer

2. Observe the air valve for movement while the engine is cranking.

Note: Movement of the air valve will be minimal at cranking speeds.

10

Does the air valve move when the engine is cranked?

1. Inspect the air intake stream to the mixer assembly and the throttle body for vacuum leaks.

2. Inspect the vacuum hoses from the mixer to the PTV solenoids for proper connection and condition.

Was a problem found and repaired?

11

12

13

14

1.6 liter Emission Certified GM Engine

__

__

__

Go to Step 12 Go to Step 9

Go to Step 11 Go to Step 10

Go to Step 26 Go to Step 24

Inspect the fuel hose connection between the LPR and the mixer assembly for damage or leakage.

Was a problem found and repaired?

1. Connect a 0-10 psi gauge to the primary test port of the low pressure regulator (LPR).

2. Crank the engine and observe the pressure reading for the LPR primary pressure.

Is the fuel pressure ABOVE the specified value?

1. Turn OFF the ignition.

2. Disconnect the LPL connector.

3. Install a test light between the pins of the LPL connector.

4. Crank the engine. The test light should illuminate.

Does the test light illuminate?

Using a DVOM, check the resistance of the low pressure lock-off (LPL).

Is the resistance within the specified range?

__

2.0 – 3.0 psi

__

12 - 24

Go to Step 26 Go to Step 12

Go to Step 22 Go to Step 13

Go to Step 14 Go to Step 16

Go to Step 15 Go to Step 23

1.6 liter Emission Certified GM Engine

1. Turn the ignition OFF.

2. Close the manual shut-off valve on the LPG tank.

15

CAUTION: When disconnecting LPG fuel lines, liquid LPG may be present. Perform this step in a well ventilated area.

16

3. Loosen the fuel inlet hose fitting at the inlet of the LPL.

Was fuel present when the fitting was loosened?

1. Turn OFF the ignition.

2. Connect the test light to chassis ground and probe pin A of the LPL connector.

3. Crank the engine. The test light should illuminate.

Does the test light illuminate?

17

18

1. Remove the LPG fuel filter / LPL.

2. Remove the filter from the LPL.

3. Empty the contents of the inlet side of the LPG fuel filter onto a clean surface.

4. Inspect the contents of the LPG fuel filter for an excessive amount of foreign material or water.

If necessary, locate and repair the source of contamination.

5. Verify the LPG fuel filter is not restricted or plugged.

Was a problem found?

The fuel supply system or hoses are plugged or restricted, locate and repair the problem.

19

20

21

Is the action complete?

Replace the fuel filter. Refer to Fuel Filter

Replacement.

Is the action complete?

Repair the open in the lock-off ground circuit.

Is the action complete?

Repair the open in the lock-off power (OEM fuel pump) circuit

.

Is the action complete?

__

__

__

__

__

__

__

LPG Fuel System Diagnostics 1B1-5

Go to Step 23 Go to Step 17

Go to Step 20 Go to Step 21

Go to Step 19 Go to Step 23

__

Go to Step 26

Go to Step 26

Go to Step 26

Go to Step 26

__

__

__

1B1-6 LPG Fuel System Diagnostics

22

Replace the low pressure regulator (LPR). Refer to

Low Pressure Regulator Replacement.

23

24

Is the action complete?

Replace the lock-off. Refer to Low Pressure Lock-

off (LPL) Replacement

.

Is the action complete?

Replace the mixer assembly. Refer to Fuel Mixer

Replacement.

Is the action complete?

The fuel supply system is operating normally, if a failure of the control solenoids is suspected. Refer to Fuel Control System Diagnosis.

25

26

1. Install the test plug in the LPR secondary chamber.

2. If you were sent to this routine by another diagnostic chart, return to the previous diagnostic procedure.

Is the action complete?

1. Disconnect all test equipment

2. Install the primary and secondary test port plugs.

3. Start the engine.

4. Using SNOOP or equivalent, leak check the test port plugs.

Is the action complete?

__

__

1.6 liter Emission Certified GM Engine

__

__

Go to Step 26

__

__

Go to Step 26

__

__

Go to Step 26

System OK

System OK

__

__

1.6 liter Emission Certified GM Engine

FUEL CONTROL DIAGNOSIS

LPG Fuel System Diagnostics 1B1-7

STEP ACTION

1 Were you referred to this procedure by another diagnostic chart?

VALUE(S)

2 Perform the On-Board Diagnostic (OBD)

System check

Are any DTC’s present in the ECM

3 Has the Fuel Ssytem diagnosis been performed?

4 1. Connect the Diagnostic Scan tool.

2. Start the engine and allow it to reach operating temperature

3. With the engine idling, observe the duty cycle reading of the PTV on the scan tool

OR

Back probe the PTV connector. Connect a duty cycle monitoring tool at the PTV connector as follows:

IMPCO FSA:

Yellow clip to pin A

Green Clip (not used for this test)

Red clip to 12V battery positive

Black Clip to battery negative

DVOM:

Back probe the PTV connector. Set the

DVOM for duty cycle percentage and connect between pin B and battery negative ground.

20% - 80%

YES NO

Go to Step 3

Go to Applicable

DTC Table

Go to Step 2

Go to Step 3

Go to Fuel system

Diagnosis

Go to Step 4

Is the PTV duty cycle within the specified range?

5 Is the PTV duty cycle ABOVE the specified value ?

6 1. Raise the engine speed to approximately

2500 RPM or greater

2.Observe the duty cycle reading of the PTV

Is the PTV duty cycle withing the specifed range?

80%

20% - 80%

Go to Step

Go to Step

Go to Step

6

7

Go to Step

Go to Step

7 Go to Step

5

6

9

1B1-8 LPG Fuel System Diagnostics

7 1. Connect the Diagnostic Scan tool.

2. Start the engine and allow it to reach operating temperature

3. With the engine idling, observe the duty cycle reading of the FTV on the scan tool

OR

Back probe the FTV connector. Contect a duty cycle monitoring tool at connector as follows:

IMPCO FSA:

Yellow clip ot pin A

Green Clip (not used for this test)

Red clip to 12V battery positive

Black Clip battery negative

DVOM:

Back probe the FTV connector. Set the

DVOM for duty cycle percentage and connect between pin B and battery negative.

20% - 80%

1.6 liter Emission Certified GM Engine

Is the FTV duty cycle within the specifed range?

8 Is the FTV duty cycle ABOVE the specified value ?

80%

Go to Step

Go to Step

9 1. Connect the negative lead of the DVOM to a know good engine ground

2. Using the positive lead of the DVOM Backprobe Pin B at the PTV connector

Was the PTV voltage within the specified range?

10 1. Turn the engine OFF

2. Disconnect the ECU connector C001

3. Disconnect the PTV electrical connector

4. Check the PTV ground circuit terminal

A for continuity to the ECU connector pin number 2.

5. Check the PTV ground circuit in Terminal A for short to ignition power or ground.

12.6 V to 15.1 V

Go to Step

24 Go to Step

12 Go to Step

12 Go to Step

8

9

10

Was a problem found?

11 Using the DVOM measure the resistance at the PTV terminals

Was the resistance measured within specification?

12 1. Connect the negative lead of the DVOM to battery negative

2. Using the positive lead of the DVOM Backprobe Pin B at the FTV connector

Was the FTV voltage within the specified range?

16.0 –24.0 Ω

12.6 V to 15.1 V

Go to Step

Go to Step

Go to Step

16 Go to Step

17 Go to Step

14 Go to Step

11

19

13

1.6 liter Emission Certified GM Engine

13 1. Turn the engine OFF

2. Disconnect the ECU connector C001

3. Disconnect the FTV electrical connector

4. Check the FTV ground circuit terminal A for continuity to the ECU connector pin 2

5. Check the FTV ground circuit in Terminal A for short to ignition power or ground.

LPG Fuel System Diagnostics 1B1-9

Was a problem found?

14 Using the DVOM measure the resistance at the FTV terminals

Was the resistance measured within specification?

15 Replace the Engine Control Unit (ECU).

Refer to Engine Control Unit (ECU) replacement

Is this action complete?

16 Repair the open or damaged circuit?

Is this action complete?

17 Check the vacuum hose to the PTV for kinks, obstruction or leakage

Was a problem found?

18 Check the fuel hose to the FTV for kinks, obstruction or leakage

Was a problem found?

19 Replace the pressure trim valve (PTV). Refer to Pressure Trim Valve (PTV) Replacement.

Is this action complete?

20 Replace the fuel trim valve (FTV). Refer to

Fuel Trim Valve (FTV) Replacement.

Is this action complete?

21 1. Return the fuel system to normal operating condition.

2. Observe the duty cycle reading

3. Raise the engine speed to approximately

2500 RPM

Is the duty cycle in the specified range?

22 Check all vacuum hoses and mixer connections for leakage.

Was a problem found?

23 Replace Mixer

Is this action complete

16.0 –24.0 Ω

20% - 80%

Go to Step

Go to Step

Go to Step

Go to Step

Go to Step

Go to Step

Go to Step

Go to Step

Go to Step

Go to Step

Go to Step

16 Go to Step

18 Go to Step

21

21

21 Go to Step

21 Go to Step

21 Go to Step

21 Go to Step

25 Go to Step

21

21

Go to Step

Go to Step

Go to Step

Go to Step

18

20

15

15

22

23

1B1-10 LPG Fuel System Diagnostics

24 The fuel control system is operating normally.

Refer to Symptoms Diagnosis

1. Disconnect all test equipment

2. If you were sent to this routine by another dianostic chart, retune to the previous diagnostic procedure,

Is this action complete

25 1. Disconnect all test equipment

2. Start the engine

3. Using a liquid leak detection solution leak check any fuel system repairs made.

Is this action complete

1.6 liter Emission Certified GM Engine

System OK

System OK

1.6 liter Emission Certified GM Engine GASOLINE Fuel System Diagnostics 1B2-1

SECTION 1B2

GASOLINE SYSTEM DIAGNOSIS

Gasoline System Description and Diagnostic Aids ..............1B2-2

Gasoline Fuel System Diagnosis ................................1B2-3-1B2-6

Go to Table of Contents

1B2–2 GASOLINE Fuel System Diagnostics

GASOLINE FUEL SYSTEM

DIAGNOSIS

1.6 liter Emission Certified GM Engine

DIAGNOSTIC AIDS

This procedure is intended to diagnose a vehicle operating on

Gasoline. If the vehicle will not continue to run on Gasoline, refer to Hard Start for preliminary checks. Before proceeding with this procedure, verify that the vehicle has a sufficient quantity of fuel.

Tools Required:

• J 34730-1 or equivalent

• J 37287 or equivalent

Diagnostic Scan Tool

• IMPCO Fuel System diagnostic tool.

Test Description

The numbers below refer to step numbers on the diagnostic table.

FUEL SYSTEM DESCRIPTION

The Engine Control Module (ECM) receives information from various engine sensors in order to control the operation of the fuel injectors. The electric fuel pump, prevents fuel flow unless the engine is cranking or running. During key on, electric fuel pump receives a two (2) second prime pulse from the ECM which allows Gasoline to flow from the tank through fuel filter and fuel lines to the fuel rails where the pressure is regulated. With Ignition “ON” and fuel pump running pressure should be 284-325 kPa (41-47 psi).

When the engine is idling, manifold pressure is low (high vacuum) and is applied to the pressure regulator diaphragm.

Vacuum will offset the spring pressure and result in very low fuel pressure. Fuel pressures at idle will vary somewhat depending on barometric pressure but, should be less then pump pressure.

Unused fuel is returned to the fuel tank by a separate return fuel line

The fuel pump pressure test port is located on the fuel rail

4. Connect fuel pressure gage as shown in illustration.

Wrap a shop towel around the fuel connection to absorb any small amount of fuel leakage that may occur when installing the gage. With ignition “ON” and the fuel pump running pressure should be 284-325 kPa (41-47 psi). This pressure is controlled by spring pressure within the regulator assembly.

6. When the engine is idling, manifold pressure is low

(High Vacuum) and is applied to the pressure regulator diaphragm. Vacuum will offset spring pressure and result in a lower pressure. Fuel pressure at idle will vary somewhat depending on barometric pressure but, should be less then the pressure noted in step 4.

11. Fuel pressure that drops off during acceleration or cruise may cause a lean condition and result in a loss of power, surging or misfire. This condition can be diagnosed using the Diagnostic Tool. If the fuel in the system is very lean the Heated Exhaust Gas Oxygen

(HEGO) will stop toggling and output voltage will drop below 300 mV. Also injector pulse will increase.

14. Fuel pressure below 284 kPa (41 psi) may cause lean condition and may set a DTC. Driveablity conditions can include hard starting cold, hesitation, and lack of power or misfire.

15. Restricting the fuel return pipe cause the fuel pressure to build above the regulated pressure. With battery voltage applied to the pump, pressure should rise above

325 kPa (47 psi) as the valve in the return pipe is partially closed.

NOTICE: Do not allow the pressure to exceed

414 kPa (60 psi) as damage to the regulator may result.

1.6 liter Emission Certified GM Engine

17. Fuel pressure above 325 kPa (47 psi) may cause a rich condition and set a DTC. Driveability may include hard starting, followed by black smoke and a strong sulphur smell in the exhaust.

GASOLINE Fuel System Diagnostics 1B2-3

26. A leaking injector can best be determined by checking for a fouled or saturated spark plug(s). If a leaking injector can not be determined by a fouled or saturated plug the following procedure should be used.

18. This test is to determine if the high fuel pressure is due to a restricted fuel return pipe or a faulty fuel pressure regulator.

21. The pressure regulator may be fitted with a screen which is designed to trap contaminants introduced during engine assembly. If dirty it can be removed with a small pick and discarded without potential harm to the regulator.

23. A system that does not hold pressure is caused by one of the following.

o Leaking fuel pump check ball

o Leaking fuel feed hose

o Leaking valve/seat within the pressure regulator

o Leaking injector

• Remove the fuel rail but leave the lines connected

• Lift the fuel rail out just enough to leave injector nozzle’s in the ports.

!

CAUTION

To reduce the risk of fire or personal injury that may result form fuel spray on the engine, make sure fuel rails is positioned over injector port and injector retaining clips are intact.

Pressurize the fuel system and observe injector nozzles.

1B2–4 GASOLINE Fuel System Diagnostics 1.6 liter Emission Certified GM Engine

Gasoline Fuel System Diagnosis

Step

1

2

3

Action

Were you referred to this procedure by a DTC diagnostic chart?

Perform the On Board Diagnostic (OBD) System

Check.

Are any DTCs present in the ECM?

Verify that the Gasoline fuel tank has a minimum of

1/4 tank of fuel,

Value(s)

__

__

__

Yes

Go to Step 3

Go to the applicable DTC

Table

No

Go to Step 2

Go to Step 3

__

4

Does the vehicle have fuel?

1. Connect a fuel pressure gage at the Schrader

Valve located on the fuel rail

2. Ignition “ON” fuel pump will run.

3. Note the pressure

4. Turn ignition off pressure may vary slightly then hold steady

285-325 kPa

(41-47 psi)

Go to Step 4

Go to Step 5 Go to Step 10

Is pressure within specified values

Did the fuel pressure hold study after the pump stopped?

5

Go to Step 6 Go to Step 22

6

1. Start engine allow it to warm to normal operating temperature at idle

2. Fuel pressure noted in step 4 should drop.

Did pressure drop by the specified value?

21-69 kPa (3-

10 psi)

Go to 27 Go to Step 7

7

8

1. Disconnect the vacuum hose from the pressure regulator

2. With the engine idling, apply 12-14 inches of vacuum to the pressure regulator, pressure should drop.

21-69 kPa (3-

10 psi)

Did the pressure drop by the specified value?

1. Locate and repair loss of vacuum to the pressure regulator.

Is the action complete?

__

Go to Step 8

Go to Step 27

Go to Step 9

1.6 liter Emission Certified GM Engine

Replace pressure regulator

9

Is the action complete?

Is pressure less then specified value?

10

11

12

13

14

15

16

17

18

GASOLINE Fuel System Diagnostics 1B2-5

__ Go to Step 27

285-325 kPa

(41-47 psi)

Go to Step 14 Go to Step 11

1. With the fuel pressure gage installed

2. Start engine and accelerate with load

Is pressure less then specified value?

1. Check for restricted fuel filter

2. Check for restricted fuel supply line from pump

Was a problem found?

285-325 kPa

(41-47 psi) Go to Step 12 Go to Step 14

Go to Step 27 Go to Step 13

1. Replace fuel pump

Is this action Complete?

With the ignition “OFF”

1. Install a 10 amp fused jumper to the B+

2. Slowly pinch the fuel return line

3. Pressure should rise

NOTE: Do not exceed 414 kPa (60 psi)

Did Pressure rise?

1. Check for restricted fuel pump strainer

2. Check for leaking fuel supply line from pump

3. Check to ensure fuel pump is correct

__

325 kPa (47 psi)

Was a problem found?

1. Replace fuel pump

__

Is this action Complete?

Is pressure greater then specified value

285-325 kPa

(41-47 psi)

1. Disconnect the fuel return hose at the fuel rail

2. Attach a length of hose to the return pipe at the rail

3. Place the other end of the hose in an approved Gasoline container

4. Turn ignition “OFF” for 10 seconds

5. Turn ignition “ON”

285-325 kPa

(41-47 psi)

Is pressure within specified value?

Go to Step 27

Go to Step 9 Go to Step 15

Go to Step 27 Go to Step 16

Go to Step 27

Go to Step 15

Go to Step 19 Go to Step 20

1B2–6 GASOLINE Fuel System Diagnostics

19

The fuel return hoses are plugged or restricted, locate and repair the problem.

Is the action complete?

Check for restricted engine return pipe

20

21

22

23

Was a problem found?

Remove pressure regulator and check for restriction

Was a problem found?

Fuel Pressure is within spec but does not hold pressure

1. Install J 37287 fuel line shut off adapter or suitable valve to close off fuel supply

2. Make sure valve is open

3. With the ignition “OFF”

4. Install a 10 amp fused jumper to the B+

5. Pressure should rise

6. Disconnect the jumper and close valve

24

25

26

27

Did pressure hold?

Check for leaking fuel pump supply line.

Was there a problem found?

Open valve in fuel pressure pipe

Reconnect test jumper and wait for pressure to build

Disconnect jumper and close valve in fuel pressure pipe

Does Pressure hold

1. Locate and correct leaking injectors

Is the action complete?

1. Disconnect all test equipment

2. Install the test port cap.

3. Start the engine.

4. Verify engine is in closed loop and no MIL is on.

Is the action complete?

__

__

__

__

__

__

1.6 liter Emission Certified GM Engine

__ __

Go to Step 27

__

__

Go to Step 27

Go To Step 21

Go to Step 27

Go to Step 9

Go to Step 23

__

Go to Step 24

Go to Step

25

Go to Step 27 Go to Step 13

Go to Step 9

Go to Step 26

Go to Step 27

System OK

__

__

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-1

SECTION 1B4

SYSTEM DIAGNOSIS

LPG System Symptoms Diagnosis:

Important Preliminary Checks ..........................................1B4-2

Intermittent Conditions ......................................................1B4-3

No Start ............................................................................1B4-4

Hard Start .........................................................................1B4-6

Cuts Out, Misses ...............................................................1B4-8

Hesitation, Sag, Stumble ..................................................1B4-9

Backfire ...........................................................................1B4-10

Lack of Power, Sluggishness, Sponginess .....................1B4-11

Poor Fuel Economy ........................................................1B4-12

Rough, Unstable, or Inccorect Idle, Stalling ....................1B4-13

Surges, Chuggles ............................................................1B4-15

Gasoline System Symptoms Diagnosis:

Important Preliminary Checks .........................................1B4-16

Intermittent Conditions .....................................................1B4-17

No Start ...........................................................................1B4-18

Hard Start ........................................................................1B4-20

Cuts Out, Misses .............................................................1B4-22

Hesitation, Sag, Stumble .................................................1B4-23

Backfire ............................................................................1B4-24

Lack of Power, Sluggishness, Sponginess ......................1B4-25

Poor Fuel Economy .........................................................1B4-26

Rough, Unstable, or Inccorect Idle, Stalling ....................1B4-27

Surges, Chuggles ............................................................1B4-28

Exhaust System Symptoms Diagnosis:

Restricted Exhaust System Diagnosis .............................1B4-29

Go to Table of Contents

1B4-2 System Diagnostics

LPG SYMPTOM DIAGNOSIS

Symptom Diagnosis

Checks

Before Using This Section

LPG Fuel System Check

Visual and Physical Checks

1.6 liter Emission Certified GM Engine

Important Preliminary Checks

Action

Before using this section, you should have performed On Board Diagnostic

Check and determined that:

1. The Control Module and MIL (Malfunction Indicator Lamp) are operating correctly.

2. There are no Diagnostic Trouble Codes (DTCs) stored, or a DTC exists but without a MIL.

Several of the following symptom procedures call for a careful visual and physical check. The visual and physical checks are very important. The checks can lead to correcting a problem without further checks that may save valuable time.

1. Verify the customer complaint.

2. Locate the correct symptom table.

3. Check the items indicated under that symptom.

4. Operate the vehicle under the conditions the symptom occurs. Verify

HEGO switching between lean and rich.

IMPORTANT!

Normal HEGO switching indicates the LPG fuel system is in closed loop and operating correctly at that time.

5. If a scan tool is available, take a snapshot under the condition that the symptom occurs. Go to Engine Scan Tool Data List to verify normal sensor values and parameters.

• Check all ECM system fuses and circuit breakers.

• Check the ECM ground for being clean, tight and in its proper location.

• Check the vacuum hoses for splits, kinks and proper connections.

• Check thoroughly for any type of leak or restriction.

• Check for air leaks at all the mounting areas of the intake manifold sealing surfaces.

• Check for proper installation of the mixer module assembly.

• Check for air leaks at the mixer assembly.

• Check the ignition wires for the following conditions:

− Cracking

− Hardness

− Proper routing

− Carbon tracking

• Check the wiring for the following items:

− Proper connections, pinches or cuts.

• The following symptom tables contain groups of possible causes for each symptom. The order of these procedures is not important. If the scan tool readings do not indicate the problems, then proceed in a logical order, easiest to check or most likely to cause first.

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-3

Intermittent

Checks Action

DEFINITION: The problem may or may not turn ON the Malfunction Indicator Lamp (MIL) or store a Diagnostic Trouble

Code (DTC).

Preliminary Checks • Refer to Important Preliminary Checks.

Faulty Electrical Connections or

Wiring

• Do not use the DTC tables. If a fault is an intermittent, the use of the DTC tables may result in the replacement of good parts.

• Faulty electrical connections or wiring can cause most intermittent problems.

• Check the suspected circuit for the following conditions:

Faulty fuse or circuit breaker

Operational Test

Intermittent Malfunction Indicator

Lamp (MIL)

Loss of DTC Memory

− Connectors poorly mated

− Terminals not fully seated in the connector (backed out)

− Terminals not properly formed or damaged

− Terminal to wires poorly connected

− Terminal tension insufficient.

• Carefully remove all the connector terminals in the problem circuit in order to ensure the proper contact tension. If necessary, replace all the connector terminals in the problem circuit in order to ensure the proper contact tension.

• Checking for poor terminal to wire connections requires removing the terminal from the connector body.

If a visual and physical check does not locate the cause of the problem, drive the vehicle with a scan tool. When the problem occurs, an abnormal voltage or scan reading indicates the problem may be in that circuit.

The following components can cause intermittent MIL and no DTC(s):

• A defective relay, Control Module driven solenoid, or a switch that can cause electrical system interference. Normally, the problem will occur when the faulty component is operating.

• The improper installation of electrical devices, such as lights, 2-way radios, electric motors, etc.

• The ignition secondary voltage shorted to a ground.

• The Malfunction Indicator Lamp (MIL) circuit or the Diagnostic Test Terminal intermittently shorted to ground.

• The Control Module grounds.

To check for the loss of the DTC Memory:

1. Disconnect the TMAP sensor.

2. Idle the engine until the Malfunction Indicator Lamp illuminates.

The ECU should store a TMAP DTC. The TMAP DTC should remain in the memory when the ignition is turned OFF. If the TMAP DTC does not store and remain, the ECM is faulty.

Additional Checks .

1B4-4 System Diagnostics 1.6 liter Emission Certified GM Engine

No Start

Checks

DEFINITION: The engine cranks OK but does not start.

Preliminary Checks

Control Module Checks

Action

Refer to Important Preliminary Checks.

If a scan tool is available:

• Check for proper communication with both the ECM

Sensor Checks

Fuel System Checks

Ignition System Checks

• Check the 3A inline fuse in the ECM battery power circuit. Refer to

Engine Controls Schematics.

• Check battery power, ignition power and ground circuits to the ECM.

Refer to Engine Control Schematics. Verify voltage and/or continuity for each circuit.

• Check the TMAP sensor.

• Check the Magnetic pickup sensor (RPM).

.

Important: A closed LPG manual fuel shut off valve will create a no start condition.

• Check for air intake system leakage between the mixer and the throttle body.

• Verify proper operation of the low pressure lock-off solenoids.

• Verify proper operation of the fuel control solenoids.

• Check the fuel system pressures. Refer to the LPG Fuel System

Diagnosis.

• Check for proper mixer air valve operation.

Note: LPG being a gaseous fuel requires higher secondary ignition system voltages for the equivalent gasoline operating conditions.

• Check for the proper ignition voltage output with J 26792 or the equivalent.

• Verify that the spark plugs are correct for use with LPG (R42LTS)

• Check the spark plugs for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

• Check for bare or shorted ignition wires.

• Check for loose ignition coil connections at the coil.

1.6 liter Emission Certified GM Engine

Engine Mechanical Checks

Exhaust System Checks

System Diagnostics 1B4-5

Important: The LPG Fuel system works on a fumigation principle of fuel introduction and is more sensitive to intake manifold leakage than the gasoline fuel supply system.

• Check for the following:

− Vacuum leaks

− Improper valve timing

− Low compression

− Bent pushrods

− Worn rocker arms

− Broken or weak valve springs

− Worn camshaft lobes.

• Check the exhaust system for a possible restriction:

− Inspect the exhaust system for damaged or collapsed pipes

− Inspect the muffler for signs of heat distress or for possible internal failure.

• Check for possible plugged catalytic converter . Refer to Restricted

Exhaust System Diagnosis

1B4-6 System Diagnostics 1.6 liter Emission Certified GM Engine

Hard Start

Checks Action

DEFINITION: The engine cranks OK, but does not start for a long time. The engine does eventually run, or may start but immediately dies.

Preliminary Checks • Refer to Important Preliminary Checks.

Sensor Checks

Fuel System Checks

• Make sure the vehicle’s operator is using the correct starting procedure.

• Check the Engine Coolant Temperature sensor with the scan tool. Compare the engine coolant temperature with the ambient air temperature on a cold engine. IF the coolant temperature reading is more than 5 degrees greater or less than the ambient air temperature on a cold engine, check for high resistance in the coolant sensor circuit.

Refer to DTC 111

• Check the Crankshaft Position (CKP) sensor.

• Check the Throttle position (TPS) and Foot Pedal Position (FPP) sensor.

Important: A closed LPG manual fuel shut off valve will create an extended crank OR no start condition.

• Verify the excess flow valve in the LPG manual shut-off valve is not tripped.

• Check mixer module assembly for proper installation and leakage.

• Verify proper operation of the low pressure lock-off solenoids.

• Verify proper operation of the PTV and FTV.

• Check for air intake system leakage between the mixer and the throttle body.

• Check the fuel system pressures. Refer to the Fuel System Diagnosis.

Ignition System Checks Note: LPG being a gaseous fuel requires higher secondary ignition system voltages for the equivalent gasoline operating conditions.

• Check for the proper ignition voltage output with J 26792 or the equivalent.

• Verify that the spark plugs are correct for use with LPG (R42LTS)

• Check the spark plugs for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

• Check for bare or shorted ignition wires.

• Check for moisture in the distributor cap if applicable.

• Check for loose ignition coil connections.

Important:

1. If the engine starts but then immediately stalls, check Crankshaft Position

(CKP) sensor.

2. Check for improper gap, debris or faulty connections.

1.6 liter Emission Certified GM Engine

Engine Mechanical Checks

Exhaust System Checks

System Diagnostics 1B4-7

Important: The LPG Fuel system works on a fumigation principle of fuel introduction and is more sensitive to intake manifold leakage than the gasoline fuel supply system.

• Check for the following:

− Vacuum leaks

− Improper valve timing

− Low compression

− Bent pushrods

− Worn rocker arms

− Broken or weak valve springs

− Worn camshaft lobes. Ref

• Check the intake and exhaust manifolds for casting flash.

• Check the exhaust system for a possible restriction:

− Inspect the exhaust system for damaged or collapsed pipes

− Inspect the muffler for signs of heat distress or for possible internal failure.

• Check for possible plugged catalytic converter. Refer to Restricted

Exhaust System Diagnosis.

1B4-8 System Diagnostics 1.6 liter Emission Certified GM Engine

Cuts Out, Misses

Checks Action

DEFINITION: A surging or jerking that follows engine speed, usually more pronounced as the engine load increases which is not normally felt above 1500 RPM. The exhaust has a steady spitting sound at idle, low speed, or hard acceleration for the fuel starvation that can cause the engine to cut-out.

Preliminary Checks

Ignition System Checks

• Refer to Important Preliminary Checks.

• Start the engine.

Engine Mechanical Checks

Fuel System Checks

• Wet down the secondary ignition system with water from a spray bottle, and look/listen for arcing or misfiring as you apply water.

• Check for proper ignition output voltage with spark tester J 26792.

• Check for a cylinder misfire.

• Verify that the spark plugs are correct for use with LPG (R42LTS)

• Remove the spark plugs in these cylinders and check for the following conditions:

• Insulation cracks

• Wear

• Improper gap

• Burned electrodes

• Heavy deposits

• Visually/Physically inspect the secondary ignition for the following:

• Ignition wires for arcing, cross-firing and proper routing

• Ignition coils for cracks or carbon tracking

• Perform a cylinder compression check.

• Check the engine for the following:

− Improper valve timing

− Bent pushrods

− Worn rocker arms

− Worn camshaft lobes.

− Broken or weak valve springs.

• Check the intake and exhaust manifold passages for casting flash.

• Check the fuel system - plugged fuel filter, low fuel pressure, etc. Refer to

LPG Fuel System Diagnosis.

• Check the condition of the wiring to the low pressure lock-off solenoid.

Additional Check Check for Electromagnetic Interference (EMI).

• EMI on the reference circuit can cause a missing condition.

• Monitoring the engine RPM with a scan tool can detect an EMI.

• A sudden increase in the RPM with little change in the actual engine

RPM, indicates EMI is present.

• If the problem exists, check the routing of the secondary wires and the ground circuit.

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-9

Hesitation, Sag, Stumble

Checks Action

DEFINITION: The vehicle has a momentary lack of response when depressing the accelerator. The condition can occur at any vehicle speed. The condition may cause the engine to stall if it’s severe enough.

Preliminary Checks

Fuel System Checks

Refer to Important Preliminary Checks.

• Check the fuel pressure. Refer to LPG Fuel System Diagnosis.

Ignition System Checks

Additional Check

• Check for low fuel pressure during a moderate or full throttle acceleration.

If the fuel pressure drops below specification, there is possibly a faulty low pressure regulator or a restriction in the fuel system.

• Check the Manifold Absolute Pressure (MAP) sensor response and accuracy.

• Check LPL electrical connection

• Check the mixer air valve for sticking or binding.

• Check the mixer module assembly for proper installation and leakage.

• Check the PTV and FTV.

Note: LPG being a gaseous fuel requires higher secondary ignition system voltages for the equivalent gasoline operating conditions. If a problem is reported on LPG and not gasoline, do not discount the possibility of a LPG only ignition system failure and test the system accordingly.

• Check for the proper ignition voltage output with J 26792 or the equivalent.

• Verify that the spark plugs are correct for use with LPG (R42LTS)

• Check for faulty spark plug wires

• Check for fouled spark plugs.

• Check for manifold vacuum or air induction system leaks

• Check the generator output voltage.

1B4-10 System Diagnostics 1.6 liter Emission Certified GM Engine

Backfire

Checks Action

DEFINITION: The fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.

Preliminary Check

Ignition System Checks

• Refer to Important Preliminary Checks.

Important!

LPG, being a gaseous fuel, requires higher secondary ignition system voltages for the equivalent gasoline operating conditions. The ignition system must be maintained in peak condition to prevent backfire.

• Check for the proper ignition coil output voltage using the spark tester

J26792 or the equivalent.

• Check the spark plug wires by connecting an ohmmeter to the ends of each wire in question. If the meter reads over 30,000 ohms, replace the wires.

• Check the connection at ignition coil.

• Check for deteriorated spark plug wire insulation.

• Check the spark plugs. The correct spark plugs for LPG are (R42LTS)

• Remove the plugs and inspect them for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

Engine Mechanical Check

Fuel System Checks

Important!

The LPG Fuel system works on a fumigation principle of fuel introduction and is more sensitive to intake manifold leakage than a gasoline fuel supply system.

• Check the engine for the following:

− Improper valve timing

− Engine compression

− Manifold vacuum leaks

− Intake manifold gaskets

− Sticking or leaking valves

− Exhaust system leakage

• Check the intake and exhaust system for casting flash or other restrictions.

• Perform a fuel system diagnosis. Refer to LPG Fuel System Diagnosis.

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-11

Lack of Power, Sluggishness, or Sponginess

Checks Action

DEFINITION: The engine delivers less than expected power. There is little or no increase in speed when partially applying the accelerator pedal.

Preliminary Checks • Refer to Important Preliminary Checks.

Fuel System Checks

• Refer to the LPG Fuel system OBD System Check

• Compare the customer’s vehicle with a similar unit. Make sure the customer has an actual problem. Do not compare the power output of the

vehicle operating on LPG to a vehicle operating on gasoline as the fuels do have different drive feel characteristics

• Remove the air filter and check for dirt or restriction.

• Check the vehicle transmission Refer to the OEM transmission diagnostics.

• Check for a restricted fuel filter, contaminated fuel, or improper fuel pressure. Refer to LPG Fuel System Diagnosis.

• Check for the proper ignition output voltage with the spark tester J 26792 or the equivalent.

• Check for proper installation of the mixer module assembly.

• Check all air inlet ducts for condition and proper installation.

• Check for fuel leaks between the LPR and the mixer.

• Verify that the LPG tank manual shut-off valve is fully open.

• Verify that liquid fuel (not vapor) is being delivered to the LPR.

Sensor Checks

Exhaust System Checks

Engine Mechanical Check

Additional Check

• Check the Heated Exhaust Gas Oxygen Sensor (HEGO) for contamination and performance. Check for proper operation of the MAP sensor.

• Check for proper operation of the TPS and FPP sensors.

• Check the exhaust system for a possible restriction:

− Inspect the exhaust system for damaged or collapsed pipes

− Inspect the muffler for signs of heat distress or for possible internal failure.

− Check for possible plugged catalytic converter.

Check the engine for the following:

• Engine compression

• Valve timing

• Improper or worn camshaft. Refer to Engine Mechanical in the Service

Manual.

• Check the ECM grounds for being clean, tight, and in their proper locations.

• Check the generator output voltage.

• If all procedures have been completed and no malfunction has been found, review and inspect the following items:

• Visually and physically, inspect all electrical connections within the suspected circuit and/or systems.

• Check the scan tool data.

1B4-12 System Diagnostics 1.6 liter Emission Certified GM Engine

Poor Fuel Economy

Checks Action

DEFINITION: Fuel economy, as measured by refueling records, is noticeably lower than expected. Also, the economy is noticeably lower than it was on this vehicle at one time, as previously shown by an by refueling records.

Preliminary Checks • Refer to Important Preliminary Checks.

Fuel System Checks

Sensor Checks

Ignition System Checks

Cooling System Checks

Additional Check

• Check the air cleaner element (filter) for dirt or being plugged.

• Visually (Physically) check the vacuum hoses for splits, kinks, and proper connections.

• Check the operators driving habits for the following items:

− Is there excessive idling or stop and go driving?

− Are the tires at the correct air pressure?

− Are excessively heavy loads being carried?

− Is their often rapid acceleration?

• Suggest to the owner to fill the fuel tank and to recheck the fuel economy.

• Suggest that a different operator use the equipment and record the results.

• Check the LPR fuel pressure. Refer to LPG Fuel System Diagnosis.

• Check the fuel system for leakage.

• Check the Temperature Manifold Absolute Pressure (TMAP) sensor.

• Verify that the spark plugs are correct for use with LPG (R42LTS)

• Check the spark plugs. Remove the plugs and inspect them for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

• Check the ignition wires for the following items:

− Cracking

− Hardness

− Proper connections

• Check the engine thermostat for always being open or for the wrong heat range

• Check the transmission shift pattern. Refer to the OEM Transmission

Controls section the Service Manual.

• Check for dragging brakes.

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-13

Rough, Unstable, or Incorrect Idle, Stalling

Checks Action

DEFINITION: The engine runs unevenly at idle. If severe enough, the engine or vehicle may shake. The engine idle speed may vary in RPM. Either condition may be severe enough to stall the engine.

Preliminary Check

Sensor Checks

• Refer to Important Preliminary Checks.

• Check for silicon contamination from fuel or improperly used sealant. The sensor will have a white powdery coating. The sensor will result in a high but false signal voltage (rich exhaust indication). The ECM will reduce the amount of fuel delivered to the engine causing a severe driveability problem.

Fuel System Checks

Ignition System Checks

Additional Checks

• Check the Heated Exhaust Gas Oxygen Sensor (HEGO) performance:

• Check the Temperature Manifold Absolute Pressure (TMAP) sensor response and accuracy.

• Check for rich or lean symptom that causes the condition. Drive the vehicle at the speed of the complaint. Monitoring the oxygen sensors will help identify the problem.

• Check for a sticking mixer air valve.

• Verify proper operation of the PTV and FTV.

• Perform a cylinder compression test. Refer to Engine Mechanical in the

Service Manual.

• Check the LPR fuel pressure. Refer to the LPG Fuel System Diagnosis.

• Check mixer module assembly for proper installation and connection.

• Check for the proper ignition output voltage using the spark tester J26792 or the equivalent.

• Verify that the spark plugs are correct for use with LPG (R42LTS)

• Check the spark plugs. Remove the plugs and inspect them for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Blistered insulators

− Heavy deposits

• Check the spark plug wires by connecting an ohmmeter to the ends of each wire in question. If the meter reads over 30,000 ohms, replace the wires.

Important: The LPG Fuel system works on a fumigation principle of fuel introduction and is more sensitive to intake manifold leakage than the gasoline fuel supply system.

• Check for vacuum leaks. Vacuum leaks can cause a higher than normal idle and low throttle angle control command.

• Check the ECU grounds for being clean, tight, and in their proper locations.

• Check the battery cables and ground straps. They should be clean and secure. Erratic voltage may cause all sensor readings to be skewed resulting in poor idle quality..

1B4-14 System Diagnostics

Engine Mechanical Check • Check the engine for the following:

− Broken motor mounts

− Improper valve timing

− Low compression

− Bent pushrods

− Worn rocker arms

− Broken or weak valve springs

− Worn camshaft lobes

1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-15

Surges/Chuggles

Checks Action

DEFINITION: The engine has a power variation under a steady throttle or cruise. The vehicle feels as if it speeds up and slows down with no change in the accelerator pedal.

Preliminary Checks • Refer to Important Preliminary Checks.

Sensor Checks

Fuel System Checks

Ignition System Checks

Additional Check

• Be sure the driver understands the Torque Converter Clutch operation.

Check the Heated Exhaust Gas Oxygen Sensor (HEGO) performance.

• Check for Rich or Lean symptom that causes the condition. Drive the vehicle at the speed of the complaint. Monitoring the oxygen sensors will help identify the problem.

• Check the fuel pressure while the condition exists. Refer to LPG Fuel

System Diagnosis.

• Verify proper fuel control solenoid operation.

• Verify that the LPG manual shut-off valve is fully open.

• Check the in-line fuel filter for restrictions.

• Check for the proper ignition output voltage using the spark tester J26792 or the equivalent.

• Verify that the spark plugs are correct for use with LPG (R42LTS)

• Check the spark plugs. Remove the plugs and inspect them for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

− Check the Crankshaft Position (CKP) sensor.

• Check the ECU grounds for being clean, tight, and in their proper locations.

• Check the generator output voltage.

• Check the vacuum hoses for kinks or leaks.

• Check Transmission

1B4-16 System Diagnostics

GASOLINE SYMPTOM DIAGNOSIS

Symptom Diagnosis

Checks

Before Using This Section

LPG Fuel System Check

Visual and Physical Checks

1.6 liter Emission Certified GM Engine

Important Preliminary Checks

Action

Before using this section, you should have performed On Board Diagnostic

Check and determined that:

1. The Control Module and MIL (Malfunction Indicator Lamp) are operating correctly.

2. There are no Diagnostic Trouble Codes (DTCs) stored, or a DTC exists but without a MIL.

Several of the following symptom procedures call for a careful visual and physical check. The visual and physical checks are very important. The checks can lead to correcting a problem without further checks that may save valuable time.

1. Verify the customer complaint.

2. Locate the correct symptom table.

3. Check the items indicated under that symptom.

4. Operate the vehicle under the conditions the symptom occurs. Verify

HEGO switching between lean and rich.

IMPORTANT!

Normal HEGO switching indicates the Gasoline fuel system is in closed loop and operating correctly at that time.

5. If a scan tool is available, take a snapshot under the condition that the symptom occurs. Go to Engine Scan Tool Data List to verify normal sensor values and parameters.

• Check all ECM system fuses and circuit breakers.

• Check the ECM ground for being clean, tight and in its proper location.

• Check the vacuum hoses for splits, kinks and proper connections.

• Check thoroughly for any type of leak or restriction.

• Check for air leaks at all the mounting areas of the intake manifold sealing surfaces.

• Check for proper installation of the Throttle Body assembly.

• Check for fuel leaks at the fuel rail and injectors.

• Check the ignition wires for the following conditions:

− Cracking

− Hardness

− Proper routing

− Carbon tracking

• Check the wiring for the following items:

− Proper connections, pinches or cuts.

• The following symptom tables contain groups of possible causes for each symptom. The order of these procedures is not important. If the scan tool readings do not indicate the problems, then proceed in a logical order, easiest to check or most likely to cause first.

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-17

Intermittent

Checks Action

DEFINITION: The problem may or may not turn ON the Malfunction Indicator Lamp (MIL) or store a Diagnostic Trouble

Code (DTC).

Preliminary Checks • Refer to Important Preliminary Checks.

Faulty Electrical Connections or

Wiring

• Do not use the DTC tables. If a fault is an intermittent, the use of the DTC tables may result in the replacement of good parts.

• Faulty electrical connections or wiring can cause most intermittent problems.

• Check the suspected circuit for the following conditions:

− Faulty fuse or circuit breaker

− Connectors poorly mated

− Terminals not fully seated in the connector (backed out)

− Terminals not properly formed or damaged

Operational Test

Intermittent Malfunction Indicator

Lamp (MIL)

Loss of DTC Memory

− Terminal to wires poorly connected

− Terminal tension insufficient.

• Carefully remove all the connector terminals in the problem circuit in order to ensure the proper contact tension. If necessary, replace all the connector terminals in the problem circuit in order to ensure the proper contact tension.

• Checking for poor terminal to wire connections requires removing the terminal from the connector body.

If a visual and physical check does not locate the cause of the problem, drive the vehicle with a scan tool. When the problem occurs, an abnormal voltage or scan reading indicates the problem may be in that circuit.

The following components can cause intermittent MIL and no DTC(s):

• A defective relay, Control Module driven solenoid, or a switch that can cause electrical system interference. Normally, the problem will occur when the faulty component is operating.

• The improper installation of electrical devices, such as lights, 2-way radios, electric motors, etc.

• The ignition secondary voltage shorted to a ground.

• The Malfunction Indicator Lamp (MIL) circuit or the Diagnostic Test Terminal intermittently shorted to ground.

• The Control Module grounds.

To check for the loss of the DTC Memory:

1. Disconnect the TMAP sensor.

2. Idle the engine until the Malfunction Indicator Lamp illuminates.

The ECU should store a TMAP DTC. The TMAP DTC should remain in the memory when the ignition is turned OFF. If the TMAP DTC does not store and remain, the ECM is faulty.

Additional Checks .

1B4-18 System Diagnostics 1.6 liter Emission Certified GM Engine

No Start

Checks

DEFINITION: The engine cranks OK but does not start.

Preliminary Checks

Control Module Checks

Action

Refer to Important Preliminary Checks.

If a scan tool is available:

• Check for proper communication with both the ECM

Sensor Checks

Fuel System Checks

Ignition System Checks

Engine Mechanical Checks

• Check the 3A inline fuse in the ECM battery power circuit. Refer to

Engine Controls Schematics.

• Check battery power, ignition power and ground circuits to the ECM.

Refer to Engine Control Schematics. Verify voltage and/or continuity for each circuit.

• Check the TMAP sensor.

• Check the Crankshaft Position (CKP) sensor.

.

• Check for fuel pump electrical circuit

• Verify proper fuel pump pressure.

• Verify proper Fuel rail pressure.

• Refer to the Gasoline Fuel System Diagnosis.

• Check Electrical connections at the injectors.

• Check for the proper ignition voltage output with J 26792 or the equivalent.

• Verify that the spark plugs are correct use (R42LTS)

• Check the spark plugs for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

• Check for bare or shorted ignition wires.

• Check for loose ignition coil connections at the coil.

• Check for the following:

− Vacuum leaks

− Improper valve timing

− Low compression

− Bent pushrods

− Worn rocker arms

− Broken or weak valve springs

− Worn camshaft lobes.

1.6 liter Emission Certified GM Engine

Exhaust System Checks

System Diagnostics 1B4-19

• Check the exhaust system for a possible restriction:

− Inspect the exhaust system for damaged or collapsed pipes

− Inspect the muffler for signs of heat distress or for possible internal failure.

• Check for possible plugged catalytic converter . Refer to Restricted

Exhaust System Diagnosis

1B4-20 System Diagnostics 1.6 liter Emission Certified GM Engine

Hard Start

Checks Action

DEFINITION: The engine cranks OK, but does not start for a long time. The engine does eventually run, or may start but immediately dies.

Preliminary Checks • Refer to Important Preliminary Checks.

Sensor Checks

Fuel System Checks

Ignition System Checks

Engine Mechanical Checks

• Make sure the vehicle’s operator is using the correct starting procedure.

• Check the Engine Coolant Temperature sensor with the scan tool. Compare the engine coolant temperature with the ambient air temperature on a cold engine. IF the coolant temperature reading is more than 5 degrees greater or less than the ambient air temperature on a cold engine, check for high resistance in the coolant sensor circuit.

Refer to DTC 111

• Check the Crankshaft Position (CKP) sensor.

• Check the Throttle position (TPS) sensor.

• Check for fuel pump electrical circuit

• Verify proper fuel pump pressure.

• Verify proper Fuel rail pressure.

• Refer to the Gasoline Fuel System Diagnosis.

Check Electrical connections at the injectors

• Check for the proper ignition voltage output with J 26792 or the equivalent.

• Verify that the spark plugs are correct use (R42LTS)

• Check the spark plugs for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

• Check for bare or shorted ignition wires.

• Check for moisture in the distributor cap if applicable.

• Check for loose ignition coil connections.

Important:

1. If the engine starts but then immediately stalls, Crankshaft Position

(CKP).

2. Check for improper gap, debris or faulty connections.

• Check for the following:

− Vacuum leaks

− Improper valve timing

− Low compression

− Bent pushrods

− Worn rocker arms

− Broken or weak valve springs

− Worn camshaft lobes. Ref

• Check the intake and exhaust manifolds for casting flash.

1.6 liter Emission Certified GM Engine

Exhaust System Checks

System Diagnostics 1B4-21

• Check the exhaust system for a possible restriction:

− Inspect the exhaust system for damaged or collapsed pipes

− Inspect the muffler for signs of heat distress or for possible internal failure.

• Check for possible plugged catalytic converter. Refer to Restricted

Exhaust System Diagnosis.

1B4-22 System Diagnostics 1.6 liter Emission Certified GM Engine

Cuts Out, Misses

Checks Action

DEFINITION: A surging or jerking that follows engine speed, usually more pronounced as the engine load increases which is not normally felt above 1500 RPM. The exhaust has a steady spitting sound at idle, low speed, or hard acceleration for the fuel starvation that can cause the engine to cut-out.

Preliminary Checks

Ignition System Checks

• Refer to Important Preliminary Checks.

• Start the engine.

Engine Mechanical Checks

Fuel System Checks

• Wet down the secondary ignition system with water from a spray bottle, and look/listen for arcing or misfiring as you apply water.

• Check for proper ignition output voltage with spark tester J 26792.

• Check for a cylinder misfire.

• Verify that the spark plugs are correct use (R42LTS)

• Remove the spark plugs in these cylinders and check for the following conditions:

• Insulation cracks

• Wear

• Improper gap

• Burned electrodes

• Heavy deposits

• Visually/Physically inspect the secondary ignition for the following:

• Ignition wires for arcing, cross-firing and proper routing

• Ignition coils for cracks or carbon tracking

• Perform a cylinder compression check.

• Check the engine for the following:

− Improper valve timing

− Bent pushrods

− Worn rocker arms

− Worn camshaft lobes.

− Broken or weak valve springs.

• Check the intake and exhaust manifold passages for casting flash.

• Check the fuel system - plugged fuel filter, low fuel pressure, etc. Refer to

Gasoline Fuel System Diagnosis.

• Check the condition of the wiring to the fuel pump and injectors.

Additional Check Check for Electromagnetic Interference (EMI).

• EMI on the reference circuit can cause a missing condition.

• Monitoring the engine RPM with a scan tool can detect an EMI.

• A sudden increase in the RPM with little change in the actual engine

RPM, indicates EMI is present.

• If the problem exists, check the routing of the secondary wires and the ground circuit.

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-23

Hesitation, Sag, Stumble

Checks Action

DEFINITION: The vehicle has a momentary lack of response when depressing the accelerator. The condition can occur at any vehicle speed. The condition may cause the engine to stall if it’s severe enough.

Preliminary Checks

Fuel System Checks

Refer to Important Preliminary Checks.

• Check for fuel pump electrical circuit

Ignition System Checks

Additional Check

• Verify proper fuel pump pressure.

• Verify proper Fuel rail pressure.

• Refer to the Gasoline Fuel System Diagnosis.

• Check Electrical connections at the injectors

• Check for the proper ignition voltage output with J 26792 or the equivalent.

• Verify that the spark plugs are correct use (R42LTS)

• Check for faulty spark plug wires

• Check for fouled spark plugs.

• Check for manifold vacuum or air induction system leaks

• Check the generator output voltage.

1B4-24 System Diagnostics 1.6 liter Emission Certified GM Engine

Backfire

Checks Action

DEFINITION: The fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.

Preliminary Check

Ignition System Checks

• Refer to Important Preliminary Checks.

• Check for the proper ignition coil output voltage using the spark tester

J26792 or the equivalent.

• Check the spark plug wires by connecting an ohmmeter to the ends of each wire in question. If the meter reads over 30,000 ohms, replace the wires.

• Check the connection at each ignition coil.

• Check for deteriorated spark plug wire insulation.

• Check the spark plugs. The correct spark plugs are (R42LTS)

• Remove the plugs and inspect them for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

Engine Mechanical Check

Fuel System Checks

• Check the engine for the following:

− Improper valve timing

− Engine compression

− Manifold vacuum leaks

− Intake manifold gaskets

− Sticking or leaking valves

− Exhaust system leakage

• Check the intake and exhaust system for casting flash or other restrictions.

• Perform a fuel system diagnosis. Refer to Gasoline Fuel System

Diagnosis.

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-25

Lack of Power, Sluggishness, or Sponginess

Checks Action

DEFINITION: The engine delivers less than expected power. There is little or no increase in speed when partially applying the accelerator pedal.

Preliminary Checks • Refer to Important Preliminary Checks.

Fuel System Checks

Sensor Checks

Exhaust System Checks

• Refer to the Gasoline Fuel system Diagnostics.

• Compare the customer’s vehicle with a similar unit. Make sure the customer has an actual problem.

• Remove the air filter and check for dirt or restriction.

• Check the vehicle transmission Refer to the OEM transmission diagnostics.

• Check for a restricted fuel filter, contaminated fuel, or improper fuel pressure. Refer to Gasoline Fuel System Diagnosis.

• Check for the proper ignition output voltage with the spark tester J 26792 or the equivalent.

• Check for fuel pump electrical circuit.

• Verify proper fuel pump pressure.

• Verify proper Fuel rail pressure.

• Refer to the Gasoline Fuel System Diagnosis.

Check Electrical connections at the injectors

• Check the Heated Exhaust Gas Oxygen Sensor (HEGO) for contamination and performance. Check for proper operation of the MAP sensor.

• Check for proper operation of the TPS and FPP sensors.

• Check the exhaust system for a possible restriction:

− Inspect the exhaust system for damaged or collapsed pipes.

− Inspect the muffler for signs of heat distress or for possible internal failure.

− Check for possible plugged catalytic converter.

Engine Mechanical Check

Additional Check

Check the engine for the following:

• Engine compression.

• Valve timing.

• Improper or worn camshaft. Refer to Engine Mechanical in the Service

Manual.

• Check the ECU grounds for being clean, tight, and in their proper locations.

• Check the generator output voltage.

• If all procedures have been completed and no malfunction has been found, review and inspect the following items:

− Visually and physically, inspect all electrical connections within the suspected circuit and/or systems.

− Check the scan tool data.

1B4-26 System Diagnostics 1.6 liter Emission Certified GM Engine

Poor Fuel Economy

Checks Action

DEFINITION: Fuel economy, as measured by refueling records, is noticeably lower than expected. Also, the economy is noticeably lower than it was on this vehicle at one time, as previously shown by an by refueling records.

Preliminary Checks • Refer to Important Preliminary Checks.

Fuel System Checks

Sensor Checks

Ignition System Checks

Cooling System Checks

Additional Check

• Check the air cleaner element (filter) for dirt or being plugged.

• Visually (Physically) check the vacuum hoses for splits, kinks, and proper connections.

• Check the operators driving habits for the following items:

− Is there excessive idling or stop and go driving?

− Are the tires at the correct air pressure?

− Are excessively heavy loads being carried?

− Is their often rapid acceleration?

• Suggest to the owner to fill the fuel tank and to recheck the fuel economy.

• Suggest that a different operator use the equipment and record the results.

• Check the fuel Rail pressure. Refer to Gasoline Fuel System Diagnosis.

• Check the fuel system for leakage.

• Check the Temperature Manifold Absolute Pressure (TMAP) sensor.

• Verify that the spark plugs are correct use (R42LTS)

• Check the spark plugs. Remove the plugs and inspect them for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

• Check the ignition wires for the following items:

− Cracking

− Hardness

− Proper connections

• Check the engine thermostat for always being open or for the wrong heat range

• Check the transmission shift pattern. Refer to the OEM Transmission

Controls section the Service Manual.

• Check for dragging brakes.

1.6 liter Emission Certified GM Engine System Diagnostics 1B4-27

Rough, Unstable, or Incorrect Idle, Stalling

Checks Action

DEFINITION: The engine runs unevenly at idle. If severe enough, the engine or vehicle may shake. The engine idle speed may vary in RPM. Either condition may be severe enough to stall the engine.

Preliminary Check

Sensor Checks

• Refer to Important Preliminary Checks.

• Check for silicon contamination from fuel or improperly used sealant. The sensor will have a white powdery coating. The sensor will result in a high but false signal voltage (rich exhaust indication). The ECM will reduce the amount of fuel delivered to the engine causing a severe driveability problem.

Fuel System Checks

Ignition System Checks

Additional Checks

Engine Mechanical Check

• Check the Heated Exhaust Gas Oxygen Sensor (HEGO) performance:

• Check the Temperature Manifold Absolute Pressure (TMAP) sensor response and accuracy.

• Check for rich or lean symptom that causes the condition. Drive the vehicle at the speed of the complaint. Monitoring the oxygen sensors will help identify the problem.

• Check for a sticking mixer air valve.

• Verify proper operation of the Injectors.

• Perform a cylinder compression test. Refer to Engine Mechanical in the

Service Manual.

• Check the fuel Rail pressure. Refer to the Gasoline Fuel System Diagnosis.

• Check injector electrical connections.

• Check for the proper ignition output voltage using the spark tester J26792 or the equivalent.

• Verify that the spark plugs are correct use (R42LTS)

• Check the spark plugs. Remove the plugs and inspect them for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Blistered insulators

− Heavy deposits

• Check the spark plug wires by connecting an ohmmeter to the ends of each wire in question. If the meter reads over 30,000 ohms, replace the wires.

• Check the ECU grounds for being clean, tight, and in their proper locations.

• Check the battery cables and ground straps. They should be clean and secure. Erratic voltage may cause all sensor readings to be skewed resulting in poor idle quality..

• Check the engine for the following:

− Broken motor mounts

− Improper valve timing

− Low compression

− Bent pushrods

− Worn rocker arms

− Broken or weak valve springs

− Worn camshaft lobes

1B4-28 System Diagnostics 1.6 liter Emission Certified GM Engine

Surges/Chuggles

Checks Action

DEFINITION: The engine has a power variation under a steady throttle or cruise. The vehicle feels as if it speeds up and slows down with no change in the accelerator pedal.

Preliminary Checks • Refer to Important Preliminary Checks.

Sensor Checks

Fuel System Checks

Ignition System Checks

Additional Check

• Be sure the driver understands the Torque Converter Clutch operation.

Check the Heated Exhaust Gas Oxygen Sensor (HEGO) performance.

• Check for Rich or Lean symptom that causes the condition. Drive the vehicle at the speed of the complaint. Monitoring the oxygen sensors will help identify the problem.

• Check the fuel rail pressure while the condition exists. Refer to Gasoline

Fuel System Diagnosis.

• Verify check injector electrical connections

• Check the in-line fuel filter for restrictions.

• Check for the proper ignition output voltage using the spark tester J26792 or the equivalent.

• Verify that the spark plugs are correct use (R42LTS)

• Check the spark plugs. Remove the plugs and inspect them for the following conditions:

− Wet plugs

− Cracks

− Wear

− Improper gap

− Burned electrodes

− Heavy deposits

− Check the Crankshaft Position (CKP) sensor.

• Check the ECU grounds for being clean, tight, and in their proper locations.

• Check the generator output voltage.

• Check the vacuum hoses for kinks or leaks.

• Check Transmission

1.6 liter Emission Certified GM Engine

Restricted Exhaust System Diagnosis

System Diagnostics 1B4-29

Check at Heated Exhaust Gas Oxygen

Sensor (HEGO)

Exhaust System Description

The emission certified engine has been designed and calibrated to meet the emission standards in effect for 2004. To help meet the emission requirements the vehicle has been equipped with a Three Way

Catalytic (TWC) muffler. The catalyst muffler is a three way catalyst, sound damping and spark arresting unit. Besides controlling the noise created from the combustion process, and preventing sparks from escaping from the exhaust system the most important function is treating the exhaust gases which are created from the combustion process.

The three-way catalyst consists of a honeycomb coated with a mixture of platinum, palladium, and rhodium. The hot gases flow through the catalyst sections where an oxidation and reduction reactions take place. These chemical reactions reduce the amount of CO, HC and

NOX in the engines exhaust. The Exhaust gas then flows through the outlet.

During normal operation the exhaust system could become damaged. Damage which reduces the flow of the exhaust gas will create increased back pressure in the engine. Reduction in exhaust flow can result from crushed muffler outlets or melted catalyst brick inside the converter.

It may be necessary to measure the back pressure in the exhaust system. To determine if the back pressure in the engine is correct use the following procedure.

Diagnostic Aids

Tools Required:

• J 35314-A Exhaust Back Pressure Gage

1. Carefully remove the HEGO.

2. Install exhaust backpressure test (J35314-a) in place of the HEGO.

3. With the engine idling at normal operating temperature, observe the exhaust system back pressure reading on te gage. Reading should not exceed 8.6 kPa (1.25 psi).

4. Increase engine speed to 2000 RPM and observe gage. Reading should not exceed 20.7 kPa (3 psi).

5. If the back pressure at either speed exceeds specification, a restricted exhaust system is indicated.

6. Inspect the entire exhaust system for a collapsed pipe, heat distress or possible internal muffler failure.

7. If there are no obvious reasons for the excessive back pressure, the catalytic converter is suspected to be restricted and should be replaced using current recommended procedures.

Diagnostic Scan Tool

• IMPCO Fuel System diagnostic tool.

Figure 1 Exhaust Back Pressure Test

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-1

SECTION 1C2

ENGINE CONTROL SYSTEM ELECTRICAL

On-Vehicle Harness Repairs ................................................1C2-2 - 1C2-4

Main Engine Harness Schematic. .....................................1C2-6 - 1C2-7

Dedicated LPG Jumper Harness ........................................1C2-8 - 1C2-9

Dedicated Gasoline Jumper Harness .................................1C2-10 - 1C2-11

Harness Connector End Views ...........................................1C2-12 - 1C2-34

Go to Table of Contents

1C2-2 Engine Control System Electrical

ON-VEHICLE SERVICE WIRE HARNESS

REPAIR

The ECM/PCM harness electrically connects the ECM/

PCM to the various solenoids, electrically and sensors in vehicle engine and passenger compartment.

Wire harnesses should be replaced with proper part number harnesses. When signal wires are spliced, into a harness, use wire with high temperature insulation only.

With the low current and voltage levels found in the system, it is important that the best possible bond at all wire splices be made by soldering the splices, as shown in Figure 3-20.

Molded on connectors require complete replacement of the connector. This means splicing a new connector assembly into the harness.

Refer to Figure 1 for wiring diagrams.

CONNECTORS AND TERMINALS

Use care when probing a connector or replacing terminals in them. It is possible to short between opposite terminals. If this happens to the wrong terminal pair, it is possible to damage certain components.

Always use jumper wires between connectors, for circuit checking. NEVER probe through

1.6 liter Emission Certified GM Engine the Weather-Pack seals. Use tachometer adapter J

35812, or equivalent, which provides an easy hook up of the tach. lead. The connector test adapter kit J

35616, or equivalent, contains an assortment of flexible connectors, used to probe terminals during diagnosis.

Fuse remover and test tool BT 8616, or equivalent, is used for removing a fuse and to adapt fuse holder, with a meter, for diagnosis.

When diagnosing, open circuits are often difficult to locate by sight, because oxidation, or terminal misalignment are hidden by the connectors. Merely wiggling a connector on a sensor, or in the wiring harness, may correct the open circuit condition. This should always be considered, when an open circuit, or failed sensor is indicated. Intermittent problems may, also, be caused by oxidized or loose connections.

Before making a connector repair, be certain of the type of connector. Weather-Pack and Compact Three connectors look similar, but are serviced differently.

FIGURE 1 WIRE HARNESS REPAIR

1.6 liter Emission Certified GM Engine

Micro-Pack

Refer to Figure 2 and repair procedure for replacement of a :Micro-Pack terminal.

FIGURE 2 MICRO-PACK CONNECTOR

Engine Control System Electrical 1C2-3

If reusing the terminal, reshape the locking tang (2).

Weather-Pack

A Weather-Pack connector can be identified by a rubber seal, at the rear of the connector. This connector, which is used in the engine compartment, protects against moisture and dirt, which could create oxidation and deposits on the terminals. This protection is important, because of the very low voltage and current levels found in the electronic system.

Repair of a Weather-Pack terminal is shown in Figure

3-23. Use tool J M28742, or BT8234-A to remove the pin and sleeve

Metri-Pack

Some connectors use terminals called Metri-Pack Series

150. (Figure 3). ‘These may be used at the coolant sensor, as well as TBI units.

They are also called “Pull-To-Seat” terminals, because, to install a terminal on a wire, the wire is first inserted through the seal (5) and connector (4). The terminal is then crimped on the wire and the terminal pulled back into the connector to seat it in place.

To remove a terminal:

1. Slide the seal back on the wire.

2. Insert tool (3) BT-8518, or J 35689, or equivalent, as shown in insert “A” and “B,” to release the terminal locking tab (2).

3. Push the wire and terminal out through the connector.

FIGURE 2 METR-PACK SERIES 150 TERMINAL REMOVAL

1C2-4 Engine Control System Electrical terminals.

If removal is attempted with an ordinary pick, there is a good chance that the terminal will be bent, or deformed. Unlike standard blade type terminals, these terminals cannot be straightened once they are bent.

Make certain that the connectors are properly seated and all of the sealing rings in place, when connecting leads. The hinge type flap provides a backup, or secondary locking feature for the connector. They are used to improve the connector reliability by retaining the terminals, if the small terminal lock tangs are not positioned properly.

Weather-Pack connections cannot be replaced with standard connections. Instructions are provided with

Weather-Pack connector and terminal packages.

1.6 liter Emission Certified GM Engine

1C2-6 Engine Control System Electrical

COO1

ECM

CAM -

VBAT

VBAT

STARTER LOCKOUT

FUEL LOCKOFF

FUEL PUMP

RELAY CONTROL

TPS1

TPS2

DBW +

DBW -

OIL PRESSURE

TACH

MIL

AUX ANA PD2

AUX OUT 1

FUEL SELECT

AUX ANA PU2

GOV SELECT

GASEOUS TRIM

CAN +

CAN -

RS 232 TX

RS 232 RX

COIL 1

COIL 2

UNUSED

UNUSED

UNUSED

UNUSED

INJ 7

UNUSED

INJ +

INJ 1

INJ 2

AUX OUT 2

AUX ANA PD1

MAP

FPP

IAT

ECT

IVS

AUX ANA PU1

POWER GROUND

POWER GROUND

ANA_RTN

5 VOLT REF

VSW

EGO 1

KNK +

KNK -

CRANK +

CRANK -

CAM +

49

50

21

55

41

42

11

12

13

38

32

31

39

36

19

20

18

16

17

30

35

33

54

24

25

37

56

26

47

29

40

48

34

15

43

44

14

22

23

9

8

7

10

53

4

2

6

1

5

3

51

52

27

28

ORANGE/BLUE 16

BROWN/BLUE 16

BROWN/GREEN 16

LT BLUE/WHITE 18

TAN/DK GREEN 18

LT GRN 18

DK BLUE 18

TAN 18

YELLOW/GRAY 18

PURPLE/YELLOW 18

DK BLUE/YELLOW 18

BLACK 16

BLACK 16

BLACK/LT GREEN 18

LT GREEN/RED 18

PINK/TAN 18

DK GREEN/ORANGE 18

PURPLE/WHITE 18

WHITE/PURPLE 18

RED/TAN 16

RED/TAN 16

GRAY/ORANGE 18

WHITE/BLACK 18

TAN/BLACK 18

WHITE/LT BLUE 18

PURPLE/LT BLUE 18

LT BLUE/DK BLUE 18

PINK/WHITE 18

TAN/ORANGE 18

LT GREEN/BLACK 18

YELLOW/LT GREEN 18

LT BLUE/BLACK 18

BLACK/WHITE 18

PURPLE/DK BLUE 18

TAN/BROWN 18

YELLOW/DK BLUE 18

GRAY/DK BLUE 18

WHITE/RED 18

BLUE/PINK 18

BLUE/WHITE 18

DK GREEN 18

ORANGE 18

YELLOW 18

YELLOW/BLACK 18

RED/WHITE 18

LT GREEN/RED 18

BLK/LT GREEN 18

LT GREEN/RED 18

DK GREEN 18

ORANGE 18

BLK/LT GREEN 18

B

D

COO2

TWR

RTN

C

5V

TX

A

RX

COMM

YELLOW/BLACK 18

YELLOW 18

BLACK 16

PINK/DK GREEN 16

COO3

A

B

C

D

COIL

1.6 liter Emission Certified GM Engine

1.6L MAIN HARNESS

ORANGE/BLUE 16

BROWN/BLUE 16

BROWN/GREEN 16

WHITE/BLACK 18

WHITE/RED 18

PINK/TAN 18

RED/WHITE 18

COO4

E

F

C

D

G

H

A

B

MTRSHD8

FUEL SYSTEM INTERFACE

LT GREEN 18

LT GREEN/RED 18

TAN 18

BLACK/LT GREEN 18

COO9

2

1

4

3

BOSCH_TMAP

YELLOW GRAY 18

BLACK/LT GREEN 18 B

A

CO10

ECT

BLACK 16

BLACK 16

RED/TAN 16

RED/TAN 16

BLACK 12

G1

GROUND

PINK/TAN 18

F1

5A

PINK 18

COO5

OIL PRES

RING

BLK/LT GREEN 18

DK GREEN/ORANGE 18

PINK/DK GREEN 16

BLACK 18

COO7

B

C

D

TWR

A

HEGO

BLACK 18

PURPLE/WHITE 18

WHITE/PURPLE 18

CRANK SENSOR

COO6

BLK/LT GREEN 18

LT GREEN/RED 18

PURPLE/LT BLUE 18

LT BLUE/DK BLUE 18

PINK/WHITE 18

TAN/ORANGE 18

COO8

6

5

2

3

4

1

BOSCH THROTTLE

CO11

STARTER

SOLENOID

PINK/TAN 18

GRAY/ORANGE 18

86

STARTER_RELAY

87A

LT BLUE/PINK 16

87 PINK/BLACK 16

85

RED/TAN 14

F2

20A

RED 14 RED 12

CO12

BATT+ 1

RED 14

PINK/TAN 18

TAN/BLACK 18

30

86

85

FUEL_PUMP_RELAY

87 PINK/YELLOW 16

F4

15A

PINK/YELLOW 16

CO13

RED 12

RED 16

ALTERNATOR

RED 14

RED/TAN 14

WHITE/BLUE 18

30

86

85

POWER_RELAY

87 PINK/DK GREEN 16

F3

15A

PINK/DK GREEN 16

CO14

BATT+ 2

RED 12

RED 16

PINK/DK GREEN 16

CO15

B

A

ALTERNATOR

PINK 18

DK BLUE 18

PURPLE/YELLOW 18

BLACK/LT GREEN 18

LT GREEN/BLACK 18

LT BLUE/BLK 18

LT GREEN/RED 18

ORANGE/YELLOW 18

LT BLUE/PINK 16

PINK/BLACK 16

LT BLUE/WHITE 18

TAN/DK GREEN 18

YELLOW/LT GREEN 18

TAN/BROWN 18

GRAY/DK BLUE 18

BLUE/PINK 18

BLUE/WHITE 18

PURPLE/DK BLUE 18

CO16

G

H

J

K

E

F

A

B

C

D

VSW

FPP1

IVS

ANA RTN

OIL PRES

MIL

VREF

CHARGE VOLTS

START IN (INTERUPT TYPE)

START IN (AUTOCRANKING)

MTRTWR10

F

G

D

E

H

A

B

C

CO17

AUX OUT 2

AUX IN PD1

TACH

FUEL SELECT

GOV SELECT

CAN +

CAN -

AUX OUT 1

MTRTWR8

BLACK/WHITE 18

YELLOW/DK BLUE 18

DK BLUE/YELLOW 18

PINK/YELLOW 16

BLACK 16

PINK/DK GREEN 16

CO18

E

F

C

D

TWR

A

B

AUX IN PD2

AUX IN PU2

AUX IN PU1

FUEL PUMP

GROUND

RELAY FUSED POWER

MTRTWR6

COO1

ECM

CAM -

VBAT

VBAT

STARTER LOCKOUT

FUEL LOCKOFF

FUEL PUMP

RELAY CONTROL

TPS1

TPS2

DBW +

DBW -

OIL PRESSURE

TACH

MIL

AUX ANA PD2

AUX OUT 1

FUEL SELECT

AUX ANA PU2

GOV SELECT

GASEOUS TRIM

CAN +

CAN -

RS 232 TX

RS 232 RX

COIL 1

COIL 2

UNUSED

UNUSED

UNUSED

UNUSED

INJ 7

UNUSED

INJ +

INJ 1

INJ 2

AUX OUT 2

AUX ANA PD1

MAP

FPP

IAT

ECT

IVS

AUX ANA PU1

POWER GROUND

POWER GROUND

ANA_RTN

5 VOLT REF

VSW

EGO 1

KNK +

KNK -

CRANK +

CRANK -

CAM +

49

50

21

55

41

42

11

12

13

38

32

31

39

36

19

20

18

16

17

30

35

33

54

24

25

37

56

26

47

29

40

48

34

15

43

44

14

22

23

9

8

7

10

53

4

2

6

1

5

3

51

52

27

28

ORANGE/BLUE 16

BROWN/BLUE 16

BROWN/GREEN 16

LT BLUE/WHITE 18

TAN/DK GREEN 18

LT GRN 18

DK BLUE 18

TAN 18

YELLOW/GRAY 18

PURPLE/YELLOW 18

DK BLUE/YELLOW 18

BLACK 16

BLACK 16

BLACK/LT GREEN 18

LT GREEN/RED 18

PINK/TAN 18

DK GREEN/ORANGE 18

PURPLE/WHITE 18

WHITE/PURPLE 18

RED/TAN 16

RED/TAN 16

GRAY/ORANGE 18

WHITE/BLACK 18

TAN/BLACK 18

WHITE/LT BLUE 18

PURPLE/LT BLUE 18

LT BLUE/DK BLUE 18

PINK/WHITE 18

TAN/ORANGE 18

LT GREEN/BLACK 18

YELLOW/LT GREEN 18

LT BLUE/BLACK 18

BLACK/WHITE 18

PURPLE/DK BLUE 18

TAN/BROWN 18

YELLOW/DK BLUE 18

GRAY/DK BLUE 18

WHITE/RED 18

BLUE/PINK 18

BLUE/WHITE 18

DK GREEN 18

ORANGE 18

YELLOW 18

YELLOW/BLACK 18

RED/WHITE 18

LT GREEN/RED 18

BLK/LT GREEN 18

LT GREEN/RED 18

DK GREEN 18

ORANGE 18

BLK/LT GREEN 18

B

D

COO2

TWR

RTN

C

5V

TX

A

RX

COMM

YELLOW/BLACK 18

YELLOW 18

BLACK 16

PINK/DK GREEN 16

COO3

A

B

C

D

COIL

1.6 liter Emission Certified GM Engine

1.6L MAIN HARNESS

Engine Control System Electrical 1C2-7

ORANGE/BLUE 16

BROWN/BLUE 16

BROWN/GREEN 16

WHITE/BLACK 18

WHITE/RED 18

PINK/TAN 18

RED/WHITE 18

COO4

E

F

C

D

G

H

A

B

MTRSHD8

FUEL SYSTEM INTERFACE

COO5

OIL PRES

RING

BLACK 18

PURPLE/WHITE 18

WHITE/PURPLE 18

CRANK SENSOR

COO6

BLK/LT GREEN 18

DK GREEN/ORANGE 18

PINK/DK GREEN 16

BLACK 18

COO7

B

C

D

TWR

A

HEGO

BLK/LT GREEN 18

LT GREEN/RED 18

PURPLE/LT BLUE 18

LT BLUE/DK BLUE 18

PINK/WHITE 18

TAN/ORANGE 18

LT GREEN 18

LT GREEN/RED 18

TAN 18

BLACK/LT GREEN 18

COO9

2

1

4

3

BOSCH_TMAP

YELLOW GRAY 18

BLACK/LT GREEN 18 B

A

CO10

ECT

BLACK 16

BLACK 16

RED/TAN 16

RED/TAN 16

BLACK 12

G1

GROUND

PINK/TAN 18

F1

5A

PINK 18

COO8

6

5

2

3

4

1

BOSCH THROTTLE

CO11

STARTER

SOLENOID

PINK/TAN 18

GRAY/ORANGE 18

86

STARTER_RELAY

87A

LT BLUE/PINK 16

87 PINK/BLACK 16

85

RED/TAN 14

F2

20A

RED 14 RED 12

CO12

BATT+ 1

RED 14

PINK/TAN 18

TAN/BLACK 18

30

86

85

FUEL_PUMP_RELAY

87 PINK/YELLOW 16

F4

15A

PINK/YELLOW 16

CO13

RED 12

RED 16

ALTERNATOR

RED 14

RED/TAN 14

WHITE/BLUE 18

30

86

85

POWER_RELAY

87 PINK/DK GREEN 16

F3

15A

PINK/DK GREEN 16

CO14

BATT+ 2

RED 12

RED 16

PINK/DK GREEN 16

CO15

B

A

ALTERNATOR

PINK 18

DK BLUE 18

PURPLE/YELLOW 18

BLACK/LT GREEN 18

LT GREEN/BLACK 18

LT BLUE/BLK 18

LT GREEN/RED 18

ORANGE/YELLOW 18

LT BLUE/PINK 16

PINK/BLACK 16

LT BLUE/WHITE 18

TAN/DK GREEN 18

YELLOW/LT GREEN 18

TAN/BROWN 18

GRAY/DK BLUE 18

BLUE/PINK 18

BLUE/WHITE 18

PURPLE/DK BLUE 18

CO16

G

H

J

K

E

F

A

B

C

D

VSW

FPP1

IVS

ANA RTN

OIL PRES

MIL

VREF

CHARGE VOLTS

START IN (INTERUPT TYPE)

START IN (AUTOCRANKING)

MTRTWR10

F

G

D

E

H

A

B

C

CO17

AUX OUT 2

AUX IN PD1

TACH

FUEL SELECT

GOV SELECT

CAN +

CAN -

AUX OUT 1

MTRTWR8

BLACK/WHITE 18

YELLOW/DK BLUE 18

DK BLUE/YELLOW 18

PINK/YELLOW 16

BLACK 16

PINK/DK GREEN 16

CO18

E

F

C

D

TWR

A

B

AUX IN PD2

AUX IN PU2

AUX IN PU1

FUEL PUMP

GROUND

RELAY FUSED POWER

MTRTWR6

1C2-8 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

1.6L LPG JUMP HARNESS

RED/WHITE 18

ORANGE/LT BLUE 16

CO22

A

B

FUEL TRIM VALVE

CO23

WHITE/BLACK 18

PINK/TAN 18

A

B

FUEL LOCK OFF

WHITE/RED 18

ORANGE/LT BLUE 16

CO24

A

B

PRESS TRIM VALVE

CO04

G

B

E

D

F

A

C

H

MTRTWR8

RED/WHITE 18

WHITE/RED 18

WHITE/BLACK 18

PINK/TAN 18

ORANGE/LT BLUE 16

CO04

G

B

E

D

F

A

C

H

MTRTWR8

RED/WHITE 18

WHITE/RED 18

WHITE/BLACK 18

PINK/TAN 18

ORANGE/LT BLUE 16

1.6 liter Emission Certified GM Engine

1.6L LPG JUMP HARNESS

Engine Control System Electrical 1C2-9

RED/WHITE 18

ORANGE/LT BLUE 16

CO22

A

B

FUEL TRIM VALVE

CO23

WHITE/BLACK 18

PINK/TAN 18

A

B

FUEL LOCK OFF

WHITE/RED 18

ORANGE/LT BLUE 16

CO24

A

B

PRESS TRIM VALVE

1C2-10 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

1.6L GASOLINE JUMP

HARNESS

CO04

TWR

F

G

A

B

C

D

E

H

MTRTWR8

ORANGE/LT BLUE 16

BROWN/LT BLUE 16

BROWN/GREEN 16

INJECTOR

CYL #4

CO20

INJECTOR

CYL #3

CO21

INJECTOR

CYL #2

CO21

INJECTOR

CYL #1

CO20

1.6 liter Emission Certified GM Engine

1.6L GASOLINE JUMP

HARNESS

Engine Control System Electrical 1C2-11

CO04

TWR

F

G

A

B

C

D

E

H

MTRTWR8

ORANGE/LT BLUE 16

BROWN/LT BLUE 16

BROWN/GREEN 16

INJECTOR

CYL #4

CO20

INJECTOR

CYL #3

CO21

INJECTOR

CYL #2

CO21

INJECTOR

CYL #1

CO20

1C2-12 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

ECM CONNECTOR C001

COO1

ECM

INJ +

INJ 1

INJ 2

AUX OUT 2

AUX ANA PD1

MAP

FPP

IAT

ECT

IVS

AUX ANA PU1

POWER GROUND

POWER GROUND

ANA_RTN

5 VOLT REF

VSW

EGO 1

KNK +

KNK -

CRANK +

CRANK -

CAM +

CAM -

VBAT

VBAT

STARTER LOCKOUT

FUEL LOCKOFF

FUEL PUMP

RELAY CONTROL

TPS1

TPS2

DBW +

DBW -

OIL PRESSURE

TACH

MIL

AUX ANA PD2

AUX OUT 1

FUEL SELECT

AUX ANA PU2

GOV SELECT

GASEOUS TRIM

CAN +

CAN -

RS 232 TX

RS 232 RX

COIL 1

COIL 2

UNUSED

UNUSED

UNUSED

UNUSED

INJ 7

UNUSED

41

42

11

12

13

14

22

23

49

50

21

55

39

36

19

20

18

16

38

32

31

17

30

35

33

9

8

7

10

53

54

24

47

29

40

48

25

37

56

26

34

15

43

44

51

52

27

2

6

3

4

28

1

5

ORANGE/BLUE 16

BROWN/BLUE 16

BROWN/GREEN 16

LT BLUE/WHITE 18

TAN/DK GREEN 18

LT GRN 18

DK BLUE 18

TAN 18

YELLOW/GRAY 18

PURPLE/YELLOW 18

DK BLUE/YELLOW 18

BLACK 16

BLACK 16

BLACK/LT GREEN 18

LT GREEN/RED 18

PINK/TAN 18

DK GREEN/ORANGE 18

PURPLE/WHITE 18

WHITE/PURPLE 18

RED/TAN 16

RED/TAN 16

GRAY/ORANGE 18

WHITE/BLACK 18

TAN/BLACK 18

WHITE/LT BLUE 18

PURPLE/LT BLUE 18

LT BLUE/DK BLUE 18

PINK/WHITE 18

TAN/ORANGE 18

LT GREEN/BLACK 18

YELLOW/LT GREEN 18

LT BLUE/BLACK 18

BLACK/WHITE 18

PURPLE/DK BLUE 18

TAN/BROWN 18

YELLOW/DK BLUE 18

GRAY/DK BLUE 18

WHITE/RED 18

BLUE/PINK 18

BLUE/WHITE 18

DK GREEN 18

ORANGE 18

YELLOW 18

YELLOW/BLACK 18

RED/WHITE 18

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-13

COMMUNICATION PORT C002

A B

C D

C

D

A

B

Pin Wire Color

Orange

Dark Green

RS232 RX

RS232 TX

Lt Green/Red 5 Volt Ref

Black/Lt Green Ana Rtn

Function

1C2-14 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

COIL CONNECTOR C003

A B C D

A

B

C

D

Pin Wire Color

Yellow/Black

Yellow

Black

Coil 2

Coil 1

Function

Power Ground

Pink/Dk Green Relay Fused Power

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-15

FUEL SYSTEM CONNECTOR C004

A B C D

E F G H

F

G

D

E

H

A

B

C

Pin Wire Color

Orange/Blue INJ +

Brown/Blue INJ 1

Brown/Green INJ 2

White/Black

White/Red

Pink/Tan

Red/White not used

Function

Fuel Lockoff

Gaseous Trim

VSW

INJ 7

1C2-16 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

OIL PRESSURE CONNECTOR C005

A

Pin Wire Color Function

Lt Green/Black Oil Pressure

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-17

CRANK SENSOR CONNECTOR C006

A B C

A

B

C

Pin Wire Color Function

Black Power Ground

Purple/White Crank +

White/Purple Crank -

1C2-18 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

HEGO CONNECTOR C007

A B

C D

C

D

A

B

Pin Wire Color Function

Blk/Lt Green Analog Return

Dk Green/Orange EGO

Pink/Dk Green

Black

Coil

Power Ground

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-19

BOSCH THROTTLE CONNECTOR C008

3 2 1

6 5 4

3

4

1

2

5

6

Pin Wire Color Function

Tan/Orange DBW -

Black/Lt Green Analog Return

Lt Green/Red 5 Volt Reference

Pink/White DBW +

Lt Blue/Dk Blue TPS 2

Purple/Lt Blue TPS 1

1C2-20 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

BOSCH TMAP CONNECTOR C009

1 2 3 4

3

4

1

2

Pin Wire Color Function

Black/Lt Green Analog Return

Tan IAT

Lt Green/Red 5 Volt Reference

Lt Green MAP

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-21

ENGINE COOLANT TEMPERATURE SENSOR CONNECTOR C010

A B

A

B

Pin Wire Color Function

Yellow/Gray Engine Coolant Temp

Black/Lt Green Analog Return

1C2-22 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

STARTER SOLENOID CONNECTOR C011

A

Pin Wire Color

White

Function

Starter Relay

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-23

BATTERY CONNECTOR C012

A

Pin Wire Color

Red Battery +

Function

1C2-24 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

ALTERNATOR CONNECTOR C013

A

Pin Wire Color

Red Battery +

Function

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-25

BATTERY CONNECTOR C014

A

Pin Wire Color

Red Battery +

Function

1C2-26 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

ALTERNATOR CONNECTOR C015

A B

A

B

Pin Wire Color Function

Red Battery

Pink/Dk Green Power Relay

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-27

INSTRUMENT PANEL CONNECTOR C016

A B C D E

F G H J K

C

D

A

B

E

F

J

K

G

H

Pin Wire Color Function

Pink

Dk Blue

VSW

FPP1

Purple/Yellow IVS

Black/Lt Green Ana Return

Lt Green/Black Oil Pressure

Lt Blue/Black MIL

Lt Green/Red VREF

Orange/Yellow Charge Volts

Lt Blue/Pink

Pink/Black

Start In (Interrupt Type)

Start In (Autocranking)

1C2-28 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

INSTRUMENT PANEL CONNECTOR C017

A B C D

E F G H

G

H

E

F

C

D

A

B

Pin Wire Color Function

Lt Blue/White

Tan/Dk Green

Aux Out 2A

Aux In PD1

Yellow/Lt Green Tach

Tan/Brown Fuel Select

Grey/Dk Blue

Blue/Pink

Gov Select

Can +

Blue/White Can -

Purple/Dk Blue Aux Out 1

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-29

INSTRUMENT PANEL CONNECTOR C018

A B C

D E F

E

F

C

D

A

B

Pin Wire Color Function

Black/White Aux In PD2

Yellow/Dk Blue Aux In PU2

Dk Blue/Yellow Aux In PU1

Pink/Yellow Fuel Pump

Black Ground

Pink/Dk Green Relay Fused Power

1C2-30 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

INJECTOR CONNECTOR C020

A B

A

B

Pin Wire Color

Orange/Lt Blue INJ +

Brown/Lt Blue INJ 1

Function

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-31

ALTERNATOR C021

A B

A

C

Pin Wire Color

Orange/Blue INJ +

Brown/Green INJ 2

Function

1C2-32 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

FUEL TRIM VALVE CONNECTOR C022

A B

A

B

Pin Wire Color

Red/White Injector 7

Orange/Lt Blue Injector +

Function

1.6 liter Emission Certified GM Engine Engine Control System Electrical 1C2-33

FUEL LOCK OFF CONNECTOR C023

A B

A

B

Pin Wire Color

White/Black

Pink/Tan

Function

Fuel Lockoff

VSW

1C2-34 Engine Control System Electrical 1.6 liter Emission Certified GM Engine

PRESSURE TRIM VALVE CONNECTOR C024

A B

A

B

Pin Wire Color

White/Red Fuel Trim

Orange/Lt Blue INJ +

Function

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-1

SECTION 1C4

DIAGNOSTIC TROUBLE CODES

Definition of Terms .................................1C4-2

Diagnostic Overview ..............................1C4-3

Laptop Based Diagnostics .....................1C4-4

Blink Code Based Diagnostics .............1C4-10

Bi-Fuel Diagnostic Procedures ............1C4-11

MIL Operation Check ...........................1C4-12

DTC 111-IAT High Voltage ...................1C4-16

DTC 112-IAT Low Voltage ....................1C4-20

DTC 113-IAT Higher Than Expected 1 .1C4-24

DTC 114-IAT Higher Than Expected 2 .1C4-26

DTC 115-Oil Pressure Low ..................1C4-28

DTC 121-ECT High Voltage .................1C4-32

DTC 122-ECT Low Voltage .................1C4-36

DTC 123-ECT Higher Than Expected 1 ...1C4-40

DTC 124-ECT Higher Than Expected 2 ..1C4-42

DTC 131-MAP High Pressure .................1C4-44

DTC 132-MAP Low Voltage ....................1C4-48

DTC 134-BP High Pressure ....................1C4-52

DTC 135-BP Low Pressure .....................1C4-54

DTC 142-Crank Sync Noise .....................1C4-58

DTC 143-Never Crank Sync at Start .......1C4-62

DTC 211-C.L. Multiplier High (LPG) ........1C4-64

DTC 212-HO2S Open/Inactive ................1C4-68

DTC 221-C.L. Multplier High (Gasoline) ...1C4-72

DTC 222-C.L. Multiplier Low (Gasoline) ...1C4-74

DTC 224-C.L. Multiplier Low (LPG) ..........1C4-76

DTC 241-Adaptive Lean Fault (Gasoline) 1C4-78

DTC 242-Adaptive Rich Fault (Gasoline) 1C4-82

DTC 243-Adaptive Learn High (LPG) .......1C4-84

DTC 244-Adaptive Learn Low (LPG) .......1C4-88

DTC 261-Sytem Voltage Low ...................1C4-90

DTC 262-System Voltage High ................1C4-92

DTC 411-Injector Driver 1 Open ...............1C4-94

DTC 412-Injector Driver 1 Shorted ...........1C4-98

DTC 413-Injector Driver 2 Open .............1C4-102

DTC 414-Injector Driver 2 Shorted ........1C4-106

DTC 511-COP Failure ............................1C4-110

DTC 512-Invalid Interrupt ......................1C4-112

DTC 513-A/D Loss .................................1C4-114

DTC 514-RTI 1 Loss .............................1C4-116

DTC 515-Flash Checksum Invalid .........1C4-118

DTC 516-RAM Failure ...........................1C4-120

DTC 531-5V Ref Lower Than Expected .1C4-122

DTC 532-5V Ref Higher Than Expected 1C4-126

DTC 555-RTI 2 Loss ..............................1C4-128

DTC 556-RTI 3 Loss ..............................1C4-130

DTC 611-FPP High Voltage ...................1C4-132

DTC 612-FPP Low Voltage ....................1C4-136

DTC 613-FPP Higher Than IVS Limit ....1C4-140

DTC 614-FPP Lower Than IVS Limit ......1C4-142

DTC 631-TPS 1 Signal Voltage High ....1C4-144

DTC 632-TPS 1 Signal Voltage Low .....1C4-148

DTC 633-TPS2 Signal Voltage High .....1C4-152

DTC 634-TPS 2 Signal Voltage Low ......1C4-156

DTC 635-TPS1 Higher Than TPS 2 ......1C4-160

DTC 636-TPS1 Lower Than TPS2 ........1C4-164

DTC 637-Throttle Unable To Open .........1C4-168

DTC 638-Throttle Unable To Close ........1C4-172

DTC 651-Max Govern Speed Override ..1C4-176

DTC 652-Fuel Rev Limit ........................1C4-178

DTC 653-Spark Rev Limit ......................1C4-180

Go to Table of Contents

1C4–2 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DESCRIPTION OF ECM BASED DIAGNOSTICS

DEFINITION OF TERMS

Active Gov Mode Speed is governed by one of two modes. Isochronous, which maintains an exact speed, or Droop, which allows speed to drop a predetermined amount based on current engine load.

AL

AL Mult

Analog

Batt

BP

CHT

CL

CL Mult

Adaptive Learn

Adaptive Learn Multiplier. The adaptive learn multiplier is a correction to the fuel delivery which is expressed as a percentage (%) and stored in the ECM’s RAM.

0 to 5 volt or 0 to 12 volt signals

Battery Voltage

Barometric Pressure. The pressure of the outside air.

Cylinder Head Temperature

Closed Loop

Closed Loop Multiplier. The closed loop multiplier is a fast acting adjustment to the fuel delivery based on feedback from the HEGO. The closed loop multiplier is expressed as a percentage (%) and is not stored in the ECM’s memory.

Closed Loop

DBW

DTC

ECT

ECM

EGO

Fuel and timing modified based on feedback from the O2 sensor.

Drive by wire.

Diagnostic Trouble Code. A code which is stored in the ECM when an ECM initiated test fails.

Engine Coolant Temperature.

Engine Control Module. The computer, which controls the fuel and ignition system on the engine.

See HO2S

Foot Pedal Position.

FPP

HO2S

IAT

IVS

Heated Oxygen Sensor

Intake Air Temperature

Idle Validation Switch

Manifold Absolute Pressure. The pressure of the air in the intake manifold.

MAP

MAT

MIL ms

Manifold Air Temperature. The temperature of the air in the intake manifold

Malfunction Indicator Light. A dash mounted light that illuminates when the ECM senses a system fault.

Milli-seconds. 1/1000 of a second.

Fuel and timing based strictly on tables stored in the ECM.

Open Loop

PSIA

RAM

TPS

Pounds per square inch absolute. 14.7 psia = 0 psig

Random Access Memory. The portion of computer memory within the ECM, which changes as the engine is running and is stored while the engine is off.

Throttle Position Sensor. The throttle position sensor measures the opening of the throttle.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-3

DIAGNOSTICS OVERVIEW OF THE SPECTRUM FUEL SYSTEM

The Spectrum Fuel system has built-in diagnostics for trouble shooting. The system has a dash mounted Malfunction Indicator

Lamp (MIL) for indication of system problems.

MALFUNCTION INDICATOR LAMP (MIL)

Most engine control system related problems that affect emissions or driveability of the vehicle will set a

(DTC) Diagnostic Trouble Code and illuminate the Malfunction Indicator Lamp.

The MIL has the following functions:

1. It notifies the driver of a problem with the fuel system, ignition system, or emission control system so the driver can arrange for service as soon as possible.

2. It will display DTC’s that have been stored due to a system malfunction.

The lamp should come on when the key is in the ON position and the engine is not running. This feature verifies that the lamp is in proper working order. If the lamp does not come on with the vehicle key on/engine off, repair it as soon as possible. Once the engine is in start or run mode, the lamp should go off. If the lamp illuminates while the engine is in the start or run mode, there is a current Diagnostic Trouble Code.

Spectrum Diagnostic Trouble Codes (DTC)

Diagnostic Trouble Codes are set when the Spectrum ECM (Electronic Control Module) runs a diagnostic self-test and the test fails. When a DTC is set, the ECM will illuminate the Malfunction Indicator Lamp on the instrument panel and save the code in memory. The ECM will continue to run the self-test unless the DTC is an oxygen sensor lean, oxygen sensor rich, or an internal ECM related DTC. If the system continues to fail the test, the lamp will stay illuminated and the DTC is current (ACTIVE). All DTC’s are stored as historical faults until they are cleared. All DTC’s except the ECM related DTC’s will automatically clear from memory if the DTC does not reset within 50 consecutive engine run cycles.

While a Diagnostic Trouble Code is current for a sensor, the ECM may assign a default “limp home” value and use that value in its control algorithms. All of the system diagnostic self-tests run continuously during normal vehicle operation.

The Diagnostic Trouble Codes can be read by using either the MIL lamp or a laptop computer. Refer to Using

a Laptop Computer to Diagnose the Spectrum System and Using a Diagnostic Jumper to Diagnose the ECI

System, located in this section. Diagnostic Trouble Codes can be cleared from memory with a laptop computer or by turning the ignition key to the OFF position and removing the system main power fuse (F3) for 15 seconds.

If more than one DTC is detected, always begin with the lowest number DTC and diagnose each problem to correction unless directed to do otherwise by the fault tree. The DTC’s are numbered in order of importance.

Having DTC 112 and DTC 122, both concerning the oxygen sensor, is possible. By repairing DTC 112 first, the problem causing the DTC 122 may also be corrected.

1C4–4 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

USING A LAPTOP COMPUTER TO DIAGNOSE THE SPECTRUM SYSTEM

A laptop computer is the preferred tool for performing diagnostic testing of the Spectrum system. A laptop computer, with the system diagnostic cable and diagnostic software, is used to read and clear Diagnostic

Trouble codes. It is also used to monitor sensor and actuator values. The diagnostic software also performs several special tests.

The following procedures will assist you in using a laptop computer to diagnose the Spectrum system:

INSTALLING THE SPECTRUM DIAGNOSTIC SOFTWARE

Loading Software and Connecting the Computer

• Start Windows

Insert the Diagnostic Interface software CD.

Click on the START button.

From the Start menu, select RUN.

In the command-line text box, type the letter of your CD-ROM drive, followed by: \setup (for example,

e:\setup), then click OK.

Follow the on screen instructions.

Connecting a Laptop Computer to the Spectrum System

Connect the system diagnostic cable to the RS232 port on the back of the computer. If you do not have a RS-232 port use the USB to RS232 adapter cable.

Connect the diagnostic cable to the diagnostic connector on the engine harness. The diagnostic connector is a square 4-pin connector located near the Spectrum system ECM.

Turn the computer ON.

Start Windows.

From the Start menu select Programs.

Select IMPCO Display.

Place the ignition key in the ON position.

The system Gauge screen should now appear and a green banner in the upper left hand will read

“Connected”.

1.6 liter Emission Certified GM Engine

DIAGNOSTIC TROUBLE CODES

Diagnostic Trouble Codes 1C4-5

The System Fault screen is used to view and clear DTC’s, which have been set.

Checking Diagnostic Trouble Codes

The System Fault screen contains a listing of all of the Historic and Active DTC’s set within the system. If a

DTC is stored in memory, the screen will display that fault in the History column. If the fault is active it will also show up in that column.

Clearing Diagnostic Trouble Codes

To clear a DTC from memory use the arrow keys or mouse to move the Press the Enter key to clear the fault from memory. NOTE: Record faults before erasing them for reference during diagnostics.

1C4–6 Diagnostic Trouble Codes

DATA STREAM

1.6 liter Emission Certified GM Engine

Reading Sensor and Actuator Values

Most applicable sensor and actuator values are displayed on the Gauges screen. The display shows the value for sensors, voltages and the sensor values in engineering units.

NOTE: If a DTC for a sensor is current, the engineering value for that sensor may be a default, limp home value and the voltage value will be the actual sensor voltage. Use the voltage value when performing diagnostics unless directed to do otherwise by the diagnostic trouble tree.

1.6 liter Emission Certified GM Engine

Graphing and Data Logging

Diagnostic Trouble Codes 1C4-7

Graphing the values and voltages can be a very useful tool in doing intermittent diagnosis. The system diagnostic monitoring software includes graphing and data logging capability. These features enhance the ability to diagnose and repair possible problems with the system. The graphing feature allows sensor inputs and select control output variables to be plotted in real-time while the engine is running.

To plot a variable you must first “TAG the variable you wish to plot. To do this, use the mouse to highlight the variable, and then right click.

Next press the “P” key or double click the Plot/Log button to invoke the plotting feature. You may change the desired time interval for each display screen. The default is 10 seconds. This can be increased or decreased as necessary to display the desired results. You can also change the sample rate.

You are now ready to plot. Simply click the “START” button to observe the plotted variables. The plot sweeps across the screen from left to right. To pause the display screen press the “SPACE BAR” at any time during plotting. To continue plotting simply press the “SPACE BAR” again. To stop the plotting feature simply click the “STOP” button. To exit the plotting screen click the “CLOSE” button. The range of each variable is listed along the left side of the display and the time is listed along the bottom of the screen.

1C4–8 Diagnostic Trouble Codes

IGNITION SYSTEM TEST

1.6 liter Emission Certified GM Engine

The Spark Kill diagnostic mode allows the technician to disable the ignition on individual cylinders. If the

Spark Kill diagnostic mode is selected with the engine running below 1000 RPM, the minimum throttle command will lock into the position it was in when the test mode was entered. If the Spark System Test mode is selected with the engine running above 1000 RPM, the throttle will continue to operate normally.

Disabling Ignition Outputs

To disable the ignition system for an individual cylinder, use the mouse to highlight the “Spark Kill” button and select the desired coil. The spark output can be re-enabled by using the mouse to highlight the “Spark

Kill” button and selecting “Normal”. If the engine is running below 1000 RPM, the spark output will stay disabled for 15 seconds and then re-set. If the engine is running above 1000 RPM, the spark output will stay disabled for 5 seconds and then re-set. This test mode has a timeout of 10 minutes. Record the rpm drop related to each spark output disabled.

The Spark outputs are arranged in the order which the engine fires, not by cylinder number.

1.6 liter Emission Certified GM Engine

INJECTOR TEST

Diagnostic Trouble Codes 1C4-9

The Injector Kill mode is used to disable individual fuel injectors. If the Injector Kill mode is selected with the engine running below 1000 RPM, the minimum throttle command will lock into the position it was in when the test mode was entered. If the Injector Kill mode is selected with the engine running above 1000 RPM, the throttle will continue to operate normally.

Disabling Injectors

To disable an injector, use the mouse to select the desired. The word “Normal” will change to the Injector you have selected. The injector driver can be re-enabled by selecting again. If the engine is running below 1000

RPM, the injector driver will stay disabled for 15 seconds and then re-set. If the engine is running above 1000

RPM, the injector driver will stay disabled for 5 seconds and then re-set. Record the change in rpm or closed loop multiplier while each driver is disabled.

1C4–10 Diagnostic Trouble Codes

THROTTLE TEST

1.6 liter Emission Certified GM Engine

To select this test mode the engine must be off but the key must be in the ON position.

The DBW (Drive By Wire) test mode allows the technician to control the throttle directly with the foot pedal or throttle input and is used during the diagnostic routines specified for FPP and TPS for Spectrum systems that use DBW.

FPP position displays the current position of the foot pedal as a percentage. FPP volts display the voltage which the ECM is reading from the FPP sensor.

TPS Command displays the commanded throttle position expressed as a percentage, which is being sent to the throttle. TPS Position is the actual percent of throttle opening being sent to the ECM from the throttle. TPS volts display the actual TPS signal voltage the ECM is receiving from the throttle.

Using a Diagnostic Jumper to Diagnose the ECI System

If you do not have access to a laptop computer, it is still possible to access the Diagnostic Trouble Codes stored in the memory of the Spectrum system ECM using a diagnostic jumper and the Malfunction Indicator

Lamp. With the key off connect the diagnostic jumper to the ECI system diagnostic connector located near the ECM. The jumper will connect diagnostic pins A and D. Turn the ignition on but do not start the vehicle.

The Malfunction Indicator Lamp (MIL) will begin to flash.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-11

The MIL displays three digit codes by flashing the first digit, pausing, then flashing the second digit, pausing, and then flashing the third digit. There will be a long pause between codes. For example, a code 143 would be one flash followed by four flashes followed by three flashes.

The MIL will first display a 166 three times. Code 166 indicates that the ECM based diagnostic routines are functioning. Then, any Diagnostic Trouble Codes stored in memory will display three times each. The MIL will then start over with the code 166. If the vehicle is started while the diagnostic jumper is in place, the MIL will flash rapidly.

Diagnostic Trouble Codes may be cleared from the system ECM memory by moving the ignition key to the

OFF position and removing the (F1) system battery fuse for at least 15 seconds. Note: This will erase all of the memory in the computer including the adaptive learn.

DIAGNOSTIC PROCEDURES FOR BI-FUEL APPLICATIONS

Diagnostic Trouble Codes (DTC) will set in both propane and gasoline fuel modes. Some DTC’s are specific to either gasoline or propane, but are described in the DTC charts as such. When dealing with a fuel specific DTC, it is advised to run the diagnostic test in the fuel mode that the code was originally set. In the case of a fuel specific DTC, the diagnostic test procedures must be performed running in the fuel mode that is described for that particular DTC. An example of this would be DTC 243 Adaptive

Learn High (LPG) The diagnostic test must be run in the LPG mode for a successful repair. In the presence of multiple DTC codes always begin with the lowest number DTC and diagnose each problem to correction, unless directed to do otherwise by the DTC chart. The DTC’s are numbered in order of importance. Having DTC 112 and DTC 122, both concerning the oxygen sensor, is possible. By repairing DTC 112 first, the problem causing the DTC 122 may also be corrected.

When a DTC is set, the ECM will illuminate the Malfunction Indicator Lamp on the instrument panel and save the code in memory. The ECM will continue to run the self-test unless the DTC is an oxygen sensor lean, oxygen sensor rich, or an internal

ECM related DTC. If the system continues to fail the test, the lamp will stay illuminated and the DTC is current (ACTIVE). All

DTC’s are stored as historical faults until they are cleared. All DTC’s except the ECM related DTC’s will automatically clear from memory if the DTC does not reset within 50 consecutive engine run cycles.

While a Diagnostic Trouble Code is current for a sensor, the ECM may assign a default “limp home” value and use that value in its control algorithms. All of the system diagnostic self-tests run continuously during normal vehicle operation.

1C4–12 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

OBD System Check

Value(s)

Diagnostic Trouble Codes 1C4-13

Yes No

2

Action

Does the MIL illuminate?

• Start the engine

• Does the MIL lamp turn off?

3 • Key ON engine OFF

• Check for voltage between MIL power source and engine ground

Do you have voltage?

MIL is working properly. OBD

System Check is complete

Go to Step (10)

Go to Step (4) Repair MIL voltage source.

Refer to OEM body and chas-

Go to step (1) sis wiring dia-

Go to Step (5)

Go to Step (6) Go to Step (8)

4 Replace MIL lamp

5

6

• Disconnect ECM wire harness connector

C001

• Using a DVOM check for continuity between

MIL ground and ECM terminal 26

• Inspect the MIL lamp socket, connector C022 and ECM terminal 26 for damage, corrosion or contamination

Did you find a problem?

7

• Replace ECM

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (1)

Go to Step (7)

-

8

Go to Step (9) Go to Step (9)

9

• Back probe the MIL and ECM terminal F in connector C022

• Using a DVOM check for continuity through connector C022

Do you have continuity?

• Inspect the MIL lamp socket, connector C022 and ECM terminal 26 for damage, corrosion or contamination

Did you find a problem?

Repair the open circuit as necessary. Refer to

Wiring Repairs in Engine

Repair the open circuit as necessary. Refer to

Wiring Repairs in Engine

10 Active DTC (Diagnostic trouble code) is stored in memory. Proceed with DTC diagnosis. If no active DTC is found in ECM memory return to this page Step (11)

1C4–14 Diagnostic Trouble Codes

11 • Key OFF

• Disconnect ECM wire harness connector

C001

• Using a DVOM check for continuity between

ECM terminal 26 and battery voltage

• Do you have continuity?

1.6 liter Emission Certified GM Engine

Repair the shorted to ground circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (7)

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-15

1C4–16 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-17

DTC 111- IAT VOLTAGE HIGH (BOSCH) TMAP

Step Action

Check?

2

• Key On

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Go to OBD

System Check

Go to step (3)

Section problem

Go to

Intermittent section

Go to step (9)

Go to step (4)

3 •

Disconnect the TMAP sensor connector from the wiring and harness and jumper pins 1 and 2 together

Key On

Does the DST display IAT voltage of 0.1 volts or less?

4

• Key OFF

• Jumper TMAP sensor connector signal pin 2 to engine ground

• Key ON

5

• Does DST display IAT voltage of 0.1 volts or less?

Go to Step (7) Go to Step (6)

Go to Step (11) _

8

6 • Disconnect the ECM wire harness connector.

• Check for continuity between TMAP sensor connector signal pin 2 and ECM IAT signal pin 32.

Do you have continuity between them?

7 • Check for continuity between TMAP sensor connector ground circuit pin 1 and ECM sensor ground circuit pin 49.

Do you have continuity between them?

__

__

_

Go to step (10) Repair the circuit as necessary. Refer to

Wiring Repairs

Go to step (10) in Engine

Electrical.

Repair the circuit as neces-

Go to step (11)

sary. Refer to

Wiring Repairs in Engine

Electrical.

_

9

10

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

• Re-check wire harness and TMAP sensor connectors for damage corrosion or contamination

Were any problems found?

• Re-check wire harness and TMAP sensor connectors for damage corrosion or contamination

Were any problems found?

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical

Go to Step (5)

Go to Step (8)

1C4–18 Diagnostic Trouble Codes

11

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-111 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-19

1C4–20 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-21

DTC 112- IAT VOLTAGE LOW (BOSCH) TMAP

2

Did you perform the On-Board (OBD) System

Check?

• Key On

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Go to OBD

System Check

Go to step (3)

Section problem

Go to

Intermittent section

Go to step (4)

Go to step (5)

3

4

Disconnect the TMAP sensor wire harness connector

Key ON

Does the DST display IAT voltage of 4.9 volts or

Replace TMAP sensor.

5

6

• Disconnect ECM wire harness connector.

• Check for continuity between TMAP sensor connector ground pin 1 and TMAP sensor connector signal pin 2

• Check for continuity between TMAP sensor connector signal circuit pin 2 and engine ground.

Do you have continuity?

__

__

Go to Step (9)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

_

Go to step (6)

Go to step (7)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

7

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

Is the replacement complete?

_

Go to step (8) _

1C4–22 Diagnostic Trouble Codes

8

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-112 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-23

1C4–24 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

DTC 113-IAT Higher Than Expected 1 Bosch TMAP

Diagnostic Trouble Codes 1C4-25

Diagnostic Aids

* This fault will set when inlet air is much hotter than normal. The most common cause of high inlet air temperature is a problem with the inlet air system. Ensure that the air inlet is not obstructed, modified or damaged.

* Inspect the air inlet system for cracks or breaks that may allow unwanted under hood air in to the air inlet system

• If none of the above can be found, Follow the diagnostic steps for DTC 112-IAT Low Voltage

Bosch� TMAP.

1C4–26 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

DTC 114-IAT Higher Than Expected 2 (Bosch TMAP)

Diagnostic Trouble Codes 1C4-27

Diagnostic Aids

* This fault will set when inlet air is much hotter than normal. The most common cause of high inlet air temperature is a problem with the inlet air system. Ensure that the air inlet is not obstructed, modified or damaged.

* Inspect the air inlet system for cracks or breaks that may allow unwanted under hood air in to the air inlet system

* If none of the above can be found, Follow the diagnostic steps for DTC 112-IAT Low Voltage.

1C4–28 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-29

DTC 115- Oil Pressure Low

Step Action

1 Did you perform the On-Board (OBD) System Check?

2 • Verify that the engine has oil pressure using a mechanical oil pressure gauge before proceeding with this chart. See Engine Specifications Section

1F.

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Repair faulty

Oiling System

3

Does the engine have oil pressure?

• Key On, Engine Running DST connected in

System Data Mode

• Clear DTC 115

• Warm the engine by idling until the ECT temperature is above 160 degrees F. and has been running for at least one minute

• Increase engine speed above 1300 RPM

Does DTC115 reset and cause the engine to shut down?

Go to Step (4) Intermittent problem

Go to

Intermittent section

4

• Key OFF

• Disconnect oil pressure switch harness connector

C005

• Clear DTC 115

• Start engine, let idle for at least one minute with

ECT over 160 degrees F.

• Increase engine speed above 1300 RPM

Does DTC 115 reset?

Go to Step (6) Go to Step (5)

8

5 • Replace oil pressure switch

Is the replacement complete?

6

• Key OFF

• Disconnect ECM harness connector C001

• Using a DVOM check for continuity between oil pressure switch connector LT GRN/BLK wire and engine ground.

• Do you have continuity between them?

7 • Inspect ECM connector pin 37 for damage corrosion or contamination

Did you find a problem?

• Replace ECM

• Is the replacement complete?

Go to Step (9) -

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (9)

Go to Step (7)

Go to Step (8)

-

1C4–30 Diagnostic Trouble Codes

9 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-115 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-31

1C4–32 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

TEMPERATURE VS. RESISTANCE CHART

IAT Data:

Temp

(deg F)

248.0

239.0

221.0

203.0

185.0

167.0

149.0

131.0

104.0

77.0

50.0

23.0

-4.0

-22.0

-31.0

-40.0

Ohms

110

125

162

214

284

383

522

721

1,200

2,063

3,791

7,419

15,614

26,854

35,763

48,153

ECT

Data:

Temp

(deg F)

242.4

231.9

211.6

201.4

181.9

163.1

144.9

127.4

102.4

78.9

49.9

23.5

-5.7

-21.2

-30.8

-40.0

Ohms

101

121

175

209

302

434

625

901

1,556

2,689

5,576

11,562

28,770

49,715

71,589

99,301

Diagnostic Trouble Codes 1C4-33

1C4–34 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 121- ECT VOLTAGE HIGH

Step

1

2

Action

Did you perform the On-Board (OBD) System Check?

• Key On

• DST (Diagnostic Scan Tool) connected in System

Data Mode

Does DST display ECT voltage of 4.95 or greater?

Value(s)

-

Yes

Go to Step (2)

Go to step (3)

No

Go to OBD

System Check

Section

Intermittent problem

Go to

Intermittent section

8

9

3

4

5

6

7

Key Off

• Disconnect the ECT sensor from the wiring harness and Jumper connector terminals A and B together

Key On

Does the DST display ECT voltage of 0.05 volts or less?

• Using a DVOM check the resistance between the two terminals of the ECT sensor and compare the resistance reading to the chart

Is the resistance value correct?

See resistance chart vs. temperature in the

DTC 121 circuit description

• Replace ECT sensor

Is the replacement complete?

• Inspect the ECT wire harness connector terminals for damage, corrosion or contamination

Did you find a problem?

Key OFF

Disconnect ECM wire harness connector

• Inspect ECM connector pins 31 and 49 for damage corrosion or contamination

• Did you find a problem?

• Jumper the ECT signal pin A at the ECT connector to engine ground

Does DST display ECT voltage of 0.05 or less?

• Key OFF

• Disconnect ECM wire harness connector

• Using a DVOM check for continuity between ECT sensor ground pin B and ECM connector pin 49

Do you have continuity between them?

Go to step (4)

Go to Step (6)

Go to Step (14)

Go to Step (8)

Go to step (5)

-

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (7)

Intermittent problem

Go to

Intermittent section

Go to Step (9)

Go to Step (10)

Go to Step (12)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

1.6 liter Emission Certified GM Engine

10 • Inspect ECM connector pins 31 and 49 for damage, corrosion or contamination

11

12

13

Did you find a problem?

• Replace ECM

Is the replacement complete?

• Key OFF

• Disconnect ECM wire harness connector

• Using A DVOM check for continuity between ECT connector signal pin A and ECM connector terminal 31

Do you have continuity between them?

• Inspect ECM connector pins 31 and 49 for damage, corrosion or contamination

Did you find a problem?

14

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-121 check for any stored codes.

Does the engine operate normally with no stored codes?

Diagnostic Trouble Codes 1C4-35

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (14)

Go to Step (11)

-

Go to Step (13) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

System OK

Go to Step (11)

Go to OBD

System Check

1C4–36 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-37

DTC 122- ECT VOLTAGE LOW

Step

1

2

Action

Did you perform the On-Board (OBD) System Check?

• Key On

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

Does DST display ECT voltage of 0.05 or less?

Value(s)

_

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to step (3) Intermittent problem

Go to

Intermittent section

Go to step (4)

Go to step (5)

3

4

5

6

Key Off

Disconnect the ECT wire harness connector

Key ON

Does the DST display ECT voltage of 4.9 volts or greater?

Replace ECT sensor.

Is the replacement complete?

• Key OFF

• Disconnect ECM wire harness connector

• Check for continuity between ECT sensor connector signal pin A and ECT sensor ground pin B

Do you have continuity between them?

• Check for continuity between ECT sensor connector signal circuit pin A and engine ground.

Do you have continuity?

__

__

Go to Step (8) _

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to step (6)

Go to step (7)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

7

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

Is the replacement complete?

_

Go to step (8) _

1C4–38 Diagnostic Trouble Codes

8

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-122 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-39

1C4–40 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-41

DTC 123- ECT HIGHER THAN EXPECTED 1

Step

1

2

3

4

Action

Did you perform the On-Board (OBD) System Check?

• Key On

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Warm Engine to normal operating temperature, then run the engine above 650 rpm for 60 seconds

Does DST display ECT temperature of 230 degrees

F. or greater with the engine running over 650 rpm?

• Verify with a temperature gauge that the engine coolant is over 225 degrees F.

Does the temperature gauge indicate 225 degrees F. or greater?

Verify ECT circuit function. Follow diagnostic test procedure for DTC-122 ECT Low Voltage

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Repair Cooling system.

-

Go to step (4)

-

1C4–42 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-43

DTC 124 ECT Higher than expected 2

Step

1

2

3

4

Action

Did you perform the On-Board (OBD) System Check?

• Key On

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Warm Engine to normal operating temperature, then run the engine above 1000 rpm for 60 seconds

• Does DST display ECT temperature of 235 degrees F. or greater with the engine running over

650 rpm?

• Verify with a temperature gauge that the engine coolant is over 225 degrees F.

Does the temperature gauge indicate 230 degrees F. or greater?

Verify ECT circuit function. Follow diagnostic test procedure for DTC-122 ECT Low Voltage

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Repair Cooling system.

-

Go to step (4)

-

1C4–44 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-45

DTC 131- MAP HIGH PRESSURE (Bosch TMAP)

2

Did you perform the On-Board (OBD) System

Check?

• Key On, Engine running.

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Go to OBD

System Check

Go to step (3)

Section

problem

Go to

Intermittent section

3

Does DST display MAP pressure of 13.0 psia or greater with the engine idling?

Key OFF

Disconnect the TMAP sensor connector

• Key ON

Does the DST display MAP pressure less than 0.05 psia?

• Probe TMAP sensor connector ground circuit pin

1 with a test light connected to battery voltage.

Does the test light come on?

• Check TMAP mechanical connection for correct mounting or possible damage causing leakage.

Go to step (4)

Go to step (6)

Go to step (5) Go to step (8)

Go to step (6) Go to Step (10)

6

7

• Disconnect ECM connector and inspect terminals for damage corrosion or contamination. Is the connection OK?

Replace TMAP sensor. Is the repair complete?

Go to step (7)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

-

__ Go to step (11)

8

9

10

• Disconnect ECM connector and check for continuity between TMAP connector sensor ground pin 1 and ECM sensor ground PIN 49.

Do you have continuity between them?

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

Has TMAP mechanical connection been corrected?

Go to step (9)

Go to step (11)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

-

Go to Step (11)

-

1C4–46 Diagnostic Trouble Codes

11

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-131 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-47

1C4–48 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-49

DTC 132- MAP Low Voltage (Bosch TMAP)

2

3

4

Did you perform the On-Board (OBD) System

Check?

• Key On, Engine running.

• DSC (Diagnostic Scan Tool) connected in

System Data Mode

Does DST display MAP voltage of 0.05 or less with the engine idling?

Key OFF

Disconnect the TMAP sensor from the wiring harness

Jumper the 5 volt reference pin 3 and MAP signal circuit pin 4 together

• Key ON

Does the DST display MAP voltage of 4.5 volts or greater?

• Inspect TMAP connector and pins for corrosion, contamination or mechanical damage

Any problems found?

Go to OBD

System Check

Go to Step (3)

Section

problem

Go to

Intermittent section

Go to Step (4)

Go to step (8)

8

5

6

7

Key OFF

Disconnect ECM connector

Check for continuity between TMAP sensor connector signal pin 4 and ECM MAP signal pin 33.

Do you have continuity between them?

• Check for continuity between TMAP sensor connector 5 volt supply signal pin 3 and ECM 5 volt supply pin 50

Do you have continuity between them?

• Check for continuity between TMAP sensor connector ground pin 1 and ECM sensor ground pin 49

Do you have continuity between them?

Repair the circuit as necessary. Refer to

Wiring Repairs

Go to step (5)

in Engine

Electrical.

Go to Step (6)

Repair the circuit as neces-

Go to step (7)

sary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to step (17) Repair the circuit as necessary. Refer to

Wiring Repairs

Go to Step (9)

in Engine

Go to step (13)

• Probe MAP connector signal circuit pin 4 with a test light connected to battery voltage

Does the DST display MAP voltage of 4.0 or greater?

1C4–50 Diagnostic Trouble Codes

9

10

• Key OFF

• Disconnect ECM connector

• Check for continuity between TMAP sensor connector pin 3 and ECM 5 volt reference pin 50.

Do you have continuity between them?

• Check for continuity between TMAP sensor connector 5 volt reference pin 3 and engine ground

Do you have continuity?

11

12

13

14

• Inspect ECM and TMAP wire harness connector and terminals for corrosion, contamination or mechanical damage

Any problems found?

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

• Check for continuity between TMAP sensor connector signal circuit pin 4 and ECM signal PIN

33

Do you have continuity between them?

• Check for continuity between TMAP sensor connector signal pin 4 and engine ground

Do you have continuity?

15

16

17

• Inspect ECM connector and wire harness connector terminals for corrosion, contamination or mechanical damage

Any problems found?

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

Is the replacement complete?

Replace TMAP sensor

Is the replacement complete?

1.6 liter Emission Certified GM Engine

Go to step (10)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (11)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to step (17)

Go to Step (16)

-

Go to Step (14)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (18)

Go to step (15)

Go to Step (16)

-

Go to step (17) -

1.6 liter Emission Certified GM Engine

18 • Remove all test equipment except the DSC.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-132 check for any stored codes.

Does the engine operate normally with no stored codes?

Diagnostic Trouble Codes 1C4-51

System OK

Go to OBD

System Check

1C4–52 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-53

DTC 134- BP High Pressure (Bosch TMAP)

Step Action

Check?

2

• Key On

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

Go to OBD

System Check

Go to step (3)

Section problem

Go to

Intermittent section

Does DST display MAP pressure of 16 psia or greater?

Go to Step (3)

System Ok

-

Go to OBD

System Check

3 Replace TMAP sensor. Is the repair complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-134 check for any stored codes.

Does the engine operate normally with no stored codes?

1C4–54 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 135-BP Low Pressure (Bosch TMAP)

Conditions for Setting the DTC

3

4

1

2

BLK/LT GRN

TAN

LT GRN/RED

LT GRN

49

32

Sensor Ground

IAT Signal

5V

50

5 Volts

33 MAP Signal

ECM

Barometric Pressure

Check Condition-Key On

Fault Condition-BP less than 8.3 psia

MIL-On for active fault and for 2 seconds after active fault

Adaptive-Disabled for remainder of key on cycle

Closed Loop-Enabled

Circuit Description

The BP (Barometric Pressure) is estimated from the TMAP sensor. The barometric pressure value is used for fuel and airflow calculations. This fault sets in the event the BP value is out of the normal range.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-55

DTC 135- BP Low Pressure (Bosch TMAP)

2

Did you perform the On-Board (OBD) System

Check?

• Key On.

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Go to OBD

System Check

Go to Step (3)

Section

problem

Go to

Intermittent section

3

Does DST display BP pressure of 8.3 psia or less?

Key OFF

Disconnect the TMAP sensor from the wiring harness

Jumper the 5 volt reference pin 3 and MAP signal pin 4 together

• Key ON

Go to Step (4)

Go to step (8)

4

Does the DST display BP pressure of 16.00 psia or greater?

• Inspect TMAP connector and wire harness connector terminals for corrosion, contamination or mechanical damage

Any problems found?

8

5

6

7

• Key OFF

• Disconnect ECM connector

• Check for continuity between TMAP sensor connector pin 4 and ECM connector pin 33

Do you have continuity between them?

• Check for continuity between TMAP sensor connector 5 volt supply pin 3 and ECM connector pin 50

Do you have continuity between them?

• Check for continuity between TMAP sensor connector ground pin 1 and ECM connector pin

49

Do you have continuity between them?

Repair the circuit as necessary. Refer to

Wiring Repairs

Go to step (5)

in Engine

Electrical.

Go to Step (6)

Repair the circuit as neces-

Go to step (7)

sary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to step (17) Repair the circuit as necessary. Refer to

Wiring Repairs

Go to Step (9)

in Engine

Go to step (13)

• Remove Jumper that was installed during step 3

• Probe TMAP connector signal circuit pin 4 with a test light connected to battery voltage

Does the DST display BP pressure of 16.00 psia or greater?

1C4–56 Diagnostic Trouble Codes

9

10

• Key OFF

• Disconnect ECM connector

• Check for continuity between TMAP sensor connector pin 3 and ECM connector pin 50

Do you have continuity between them?

• Check for continuity between TMAP sensor connector 5 volt reference pin 3 and engine ground

Do you have continuity?

11

• Inspect TMAP and ECM connector pins for corrosion, contamination or mechanical damage

Any problems found?

12

13

14

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

• Check for continuity between TMAP sensor connector pin 4 and ECM pin 33

Do you have continuity between them?

• Check for continuity between TMAP sensor connector pin 4 and engine ground

Do you have continuity?

15

16

17

• Inspect ECM connector and wire harness connector pins for corrosion, contamination or mechanical damage

Any problems found?

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

Is the replacement complete?

Replace TMAP sensor

Is the replacement complete?

1.6 liter Emission Certified GM Engine

Go to step (10)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (11)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to step(17)

Go to Step (16)

-

Go to Step (14)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to step (15)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (18)

Go to Step (16)

-

Go to step (17) -

1.6 liter Emission Certified GM Engine

18

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-135 check for any stored codes.

Does the engine operate normally with no stored codes?

Diagnostic Trouble Codes 1C4-57

System OK

Go to OBD

System Check

1C4–58 Diagnostic Trouble Codes

DTC 142-Crank Sync Noise

1.6 liter Emission Certified GM Engine

Crankshaft

Crankshaft

Crank

Sensor

A

LT GRN/RED

50

B

WHT/PPL

12

C

PPL/WHT

11

ECM

5 volts +

Crank -

Crank +

Conditions for setting the DTC

Crankshaft Position sensor

Check Condition- Engine running

Fault Condition- 1 invalid crank re-sync

MIL- On during active fault and for 10 seconds after active fault

Adaptive- Disabled for the remainder of the key-on cycle

Closed Loop- Enabled

Circuit Description

The Crankshaft Position sensor is a magnetic transducer mounted on the engine block adjacent to a pulse wheel located on the crankshaft. It determines crankshaft position by monitoring the pulse wheel. The Crankshaft Position sensor is used to measure engine RPM and its signal is used to synchronize the ignition and fuel systems. The ECM must see a valid Crankshaft position signal while running. If no signal is present for 800ms or longer, this fault will set.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-59

DTC 142 Crank Sync Noise

Step

1

2

3

Action

Did you perform the On-Board (OBD) System Check?

• Check that the ECM ground terminals G1 and G2 are clean and tight

Are the ground terminals G1 and G2 clean and tight?

• Key On, Engine OFF

• Disconnect the CKP (Crankshaft position) Sensor connector C009

• Using A DVOM check for voltage at the CKP sensor connector pin A and engine ground

Do you have voltage?

Value(s)

-

5.0 volts

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

4

5

6

7

8

9

• Key OFF

• Disconnect ECM connector C001

• Using a DVOM check for continuity between CKP connector pin B and ECM connector pin 12

• Do you have continuity between them?

• Using a DVOM check for continuity between CKP connector pin C and ECM connector pin 11

Do you have continuity between them?

• Inspect the CKP connector C009 terminals for damage, corrosion or contamination

Did you find a problem?

• Inspect the ECM connector C001 terminals 11,12 and 50 for damage, corrosion or contamination

Did you find a problem

• Replace CKP sensor using R&R procedure in

Section 1E. Pay special attention to CKP sensor reluctor wheel inspection.

Is the replacement complete?

• Replace ECM

• Is the replacement complete?

Go to Step (5)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (7)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to step (8)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (10) -

Go to Step (11) -

1C4–60 Diagnostic Trouble Codes

10 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-142 check for any stored codes.

Does the engine operate normally with no stored codes?

11 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-142 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to Step (9)

System OK Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-61

1C4–62 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 143 Never Crank Sync At Start

Step

1

2

3

Action

Did you perform the On-Board (OBD) System Check?

• Check that the ECM ground terminals G1 and G2 are clean and tight

Are the ground terminals G1 and G2 clean and tight?

• Key On, Engine OFF

• Disconnect the CKP (Crankshaft position) Sensor connector C009

• Using A DVOM check for voltage at the CKP sensor connector pin A and engine ground

Do you have voltage?

Value(s)

-

5.0 volts

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

4

5

6

7

8

9

• Key OFF

• Disconnect ECM connector C001

• Using a DVOM check for continuity between CKP connector pin B and ECM connector pin 12

• Do you have continuity between them?

• Using a DVOM check for continuity between CKP connector pin C and ECM connector pin 11

Do you have continuity between them?

• Inspect the CKP connector C009 terminals for damage, corrosion or contamination

Did you find a problem?

• Inspect the ECM connector C001 terminals 11,12 and 50 for damage, corrosion or contamination

Did you find a problem

• Replace CKP sensor using CKP R&R procedure in Section 1E. Pay special attention to CKP reluctor wheel inspection

Is the replacement complete?

• Replace ECM

• Is the replacement complete?

Go to Step (5)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (7)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to step (8)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (10) -

Go to Step (11) -

1.6 liter Emission Certified GM Engine

10 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-143 check for any stored codes.

Does the engine operate normally with no stored codes?

11 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-143 check for any stored codes.

Does the engine operate normally with no stored codes?

Diagnostic Trouble Codes 1C4-63

System OK

Go to Step (9)

System OK Go to OBD

System Check

1C4–64 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 211- Closed Loop Multiplier High (LPG)

- +

Sensor

Heater

B

DK GRN/ORN

55

A

BLK/LT GRN

49

D

BLK

C

PNK/DKGRN

HO2S

Sensor Ground

ECM

To System Power Relay

To Engine Ground

Conditions for Setting the DTC

Heated Oxygen Sensor

Check Condition- Engine running

Fault Condition- Closed Loop multiplier out of range (greater than 35%)

MIL- Disabled

Adaptive- Enabled but not updated when Closed Loop is at limit

Closed Loop- Enabled

Circuit description

The HO2S sensor is used to determine if the fuel flow to the engine is correct by measuring the oxygen content in the exhaust gas. The ECM uses this information to correct the fuel flow with the Closed Loop multiplier and the adaptive multiplier. This fault sets if the Closed Loop multiplier exceeds the limits of normal operation and cannot correctly modify the fuel flow within its limits.

Diagnostic Aids

Always diagnose any ECM codes that are present before beginning this diagnostic procedure.

• Heated Oxygen sensor wires may be mis-routed and contacting the exhaust manifold.

• Vacuum leaks can cause a lean exhaust condition, especially at light load and idle conditions.

• Exhaust leaks can cause a lean exhaust condition, especially at light load and idle conditions

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-65

DTC 211- Closed Loop Multiplier High (LPG)

Step Action

1 Did you perform the On-Board (OBD) System Check?

2

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Run engine to full operating temperature and then idle for a minimum of 2 minutes

Does DST display HO2S voltage fixed below 0.35 volts after 2 minutes of idle run time?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to step (3) Intermittent

problem

Go to

Intermittent section

3 • Key OFF

• Disconnect ECM connector

• Disconnect HO2S wire harness connector

• Using a high impedance DVOM check for continuity between HO2S connector signal pin B and engine ground

Do you have continuity?

4 • Using a high impedance DVOM check for continuity between HO2S connector signal pin B and

HO2S connector sensor ground pin A

• Do you have continuity between them?

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

Go to Step (5)

5 • Refer to Diagnostic aids for DTC 211

Did you check the diagnostic Aids for DTC 211?

6 • Replace HO2S sensor

Is the replacement complete?

Go to Step (7)

1C4–66 Diagnostic Trouble Codes

7 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-211 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-67

1C4–68 Diagnostic Trouble Codes

212-HO2S Open/Inactive

1.6 liter Emission Certified GM Engine

- +

Sensor

Heater

B

DK GRN/ORN

55

A

BLK/LT GRN

49

D

BLK

C

PNK/DKGRN

HO2S

Sensor Ground

ECM

To System Power Relay

Conditions for Setting the DTC

To Engine Ground

Heated Oxygen Sensor

Check condition- Engine running

Fault condition- HO2S cold persistently more than 120 seconds

MIL- On during active fault and for 1 second after active fault

Adaptive- Disabled during active fault

Closed Loop- Disabled during active fault

Circuit Description

The HO2S sensor is used to determine if the fuel flow to the engine is correct by measuring the oxygen content in the exhaust gas. The ECM uses this information to correct the fuel flow with the Closed Loop multiplier and the Adaptive multiplier.

This fault will set if HO2S is cold, non-responsive, or inactive for 120 seconds or longer.

1.6 liter Emission Certified GM Engine

DTC 212- HO2S Open/Inactive

Diagnostic Trouble Codes 1C4-69

Step Action

1 Did you perform the On-Board (OBD) System Check?

2

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (5) Go to Step (3)

• Key ON, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Run engine to full operating temperature and then idle for a minimum of 2 minutes

Does DST display HO2S voltage fixed between 0.4 and 0.5 volts after 2 minutes of idle run time?

3 • Back probe HO2S wire harness connector and check for voltage between HO2S connector heater ground pin D and battery voltage positive.

Do you have power?

4

• Back probe HO2S wire harness connector and check for voltage between HO2S connector heater power pin C and engine ground.

Do you have power?

5 • Key OFF

• Disconnect HO2S connector and ECM connector.

• Key ON

• Check for continuity between HO2S sensor connector ground pin A and ECM HO2S sensor ground PIN 49.

Do you have continuity between them?

6

• Check for continuity between HO2S sensor connector signal pin B and ECM connector HO2S signal pin 55

Do you have continuity between them?

7 Replace HO2S Sensor

Is the replacement complete?

Go to step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to step (7)

Repair the circuit as necessary.

Check

System Power

Relay circuit. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

Repair the circuit as necessary.

Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (8) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (9)

-

1C4–70 Diagnostic Trouble Codes

8 • Inspect ECM connector pins 49 and 55 for damage, corrosion or contamination

• Inspect HO2S connector terminals A, B, C and D for damage, corrosion or contamination

9

Did you find a problem?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-212 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

Repair the circuit as necessary. Refer to

Go to Step (7)

Wiring Repairs in Engine

Electrical.

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-71

1C4–72 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 221-Closed Loop Multiplier High (Gasoline)

- +

Sensor

Heater

B

DK GRN/ORN

55

A

BLK/LT GRN

49

D

BLK

C

PNK/DKGRN

HO2S

Sensor Ground

ECM

To System Power Relay

To Engine Ground

Conditions for Setting the DTC

Heated Oxygen Sensor

Functional Fault-Closed Loop multiplier out of range (at limit of 35%)

MIL-On during active fault

Adaptive-Enabled

Closed Loop-Enabled

Circuit Description

The HO2S sensor is used to determine if the fuel flow to the engine is correct by measuring the oxygen content in the exhaust gas. The ECM uses this information to correct the fuel flow with the Closed Loop multiplier and the Adaptive multiplier.

This fault sets if the Closed Loop multiplier exceeds the limits of normal operation. When the multiplier cannot correctly modify the fuel flow within its limits, the limit is enforced.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-73

DTC 221 Closed Loop Multiplier High (Gasoline)

Step Action

1 Did you perform the On-Board (OBD) System Check?

2

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Run engine to full operating temperature and then idle for a minimum of 2 minutes

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to step (3) Intermittent problem

Go to

Intermittent section

Does DST display HO2S voltage fixed below 0.35 volts after 2 minutes of idle run time?

3 • Key OFF

• Disconnect HO2S sensor wire harness connector

• Disconnect ECM connector

• Using a high impedance DVOM Check for continuity between HO2S connector signal pin B and engine ground

Do you have continuity?

4 • Using a high impedance DVOM Check for continuity between HO2S connector signal pin B and

HO2S sensor ground pin A

Do you have continuity?

Repair the circuit as required

Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as required

Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

Go to Step (4)

Go to Step (5)

-

5 • Refer to Diagnostic aids for DTC 221

Did you check the diagnostic Aids for DTC 221?

6 • Replace HO2S sensor

Is the replacement complete?

• Remove all test equipment except the DST.

7

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-221 check for any stored codes.

Does the engine operate normally with no stored codes?

Go to Step (7) -

1C4–74 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 222- Closed Loop Multiplier Low (Gasoline)

- +

Sensor

Heater

B

DK GRN/ORN

55

A

BLK/LT GRN

49

D

BLK

C

PNK/DKGRN

HO2S

Sensor Ground

ECM

To System Power Relay

To Engine Ground

Conditions for Setting the DTC

Heated Oxygen Sensor

Functional Fault-Closed Loop multiplier out of range (at limit of -35%)

MIL-On during active fault and for one update after active fault

Adaptive-Enabled

Closed Loop-Enabled

Circuit Description

The HO2S (Heated Oxygen Sensor) sensor is used to determine if the fuel flow to the engine is correct by measuring the oxygen content in the exhaust gas. The ECM uses this information to correct the fuel flow with the Closed Loop multiplier and the adaptive multiplier. This fault sets if the Closed Loop multiplier exceeds the limits of normal operation. When the multiplier cannot correctly modify the fuel flow within its limits, it is limited at -35%.

Diagnostic Aids

Always diagnose any other ECM codes that are present before beginning this diagnostic procedure.

Fuel System The system will be rich if an injector fails in an open manner. High fuel pressure due to a faulty fuel regulator or obstructed fuel return line will cause the system to run rich.

Ignition noise open or poor ground circuit to or in the ignition system or ECM may cause EMI (Electromagnetic interference). This noise could be interpreted by the ECM as ignition pulses, and the sensed RPM becomes higher than the actual speed. The ECM then delivers too much fuel, causing the system to run rich.

TMAP Sensor A higher manifold pressure than normal can cause the system to go rich. Temporarily disconnecting the MAP Sensor will allow the ECM to set a default value for MAP.

IAT Sensor Check for a shifted sensor that could cause the ECM to sense lower than actual temperature of incoming air. This can cause a rich exhaust condition.

ECT Sensor Check for a skewed sensor that could cause the ECM to sense engine temperature colder than it actually is. This could also cause a rich exhaust condition.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-75

DTC 222- Closed Loop Multiplier Low (Gasoline)

Step Action

1 Did you perform the On-Board (OBD) System Check?

2

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Run engine to full operating temperature and then idle for a minimum of 2 minutes

Does DST display HO2S voltage fixed above 0.7 volts after 2 minutes of idle run time?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to step (3) Intermittent

problem

Go to

Intermittent section

3 • Key OFF

• Disconnect HO2S wire harness connector

• Disconnect ECM wiring harness connector

• Key ON

• Using a high impedance DVOM check for voltage between HO2S connector signal pin B and engine ground

Do you have voltage?

Repair the circuit as required

Refer to

Wiring Repairs in Engine

Electrical.

Refer to

Diagnostic Aids for DTC 222

1C4–76 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 224- Closed Loop Multiplier Low (LPG)

- +

Sensor

Heater

B

DK GRN/ORN

55

A

BLK/LT GRN

49

D

BLK

C

PNK/DKGRN

HO2S

Sensor Ground

ECM

To System Power Relay

To Engine Ground

Conditions for Setting the DTC

Heated Oxygen Sensor

Functional Fault-Closed Loop multiplier out of range (at limit of -35%)

MIL Disabled

Adaptive-Disabled

Closed Loop-Enabled

Circuit Description

The HO2S (Heated Oxygen Sensor) sensor is used to determine if the fuel flow to the engine is correct by measuring the oxygen content in the exhaust gas. The ECM uses this information to correct the fuel flow with the Closed Loop multiplier and the adaptive multiplier. This fault sets if the Closed Loop multiplier exceeds the limits of normal operation. When the multiplier cannot correctly modify the fuel flow within its limits, it is limited at -35%.

Diagnostic Aids

Always diagnose any other ECM codes that are present before beginning this diagnostic procedure.

Fuel System High secondary fuel pressure can cause the system to run rich. A worn fuel mixer, faulty PTV (pressure trim valve) or FTV

(fuel trim valve) can also cause the system to run rich.

Fuel Quality A drastic variation in fuel quality (very high butane content) may cause the system to run rich. Be sure that the specified

HD-5 or HD-10 motor fuel grade propane is used.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-77

DTC 224- Closed Loop Multiplier Low (LPG)

Step Action

1 Did you perform the On-Board (OBD) System Check?

2

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Run engine to full operating temperature and then idle for a minimum of 2 minutes

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to step (3) Intermittent

problem

Go to

Intermittent section

3

Does DST display HO2S voltage fixed above 0.7 volts after 2 minutes of idle run time?

• Key OFF

• Disconnect HO2S wire harness connector

• Disconnect ECM wiring harness connector

• Key ON

• Using a high impedance DVOM check for voltage between HO2S connector signal pin B and engine ground

Do you have voltage?

Repair wire harness shorted signal to voltage

Refer to

Wiring Repairs in Engine

Electrical.

Refer to

Diagnostic Aids for DTC 224

1C4–78 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 241-Adaptive Lean Fault (high limit-gasoline)

- +

Sensor

Heater

B

DK GRN/ORN

55

A

BLK/LT GRN

49

D

BLK

C

PNK/DKGRN

HO2S

Sensor Ground

ECM

To System Power Relay

To Engine Ground

Conditions for Setting the DTC

Heated Oxygen Sensor

Functional Fault-Adaptive multiplier out of range (greater than 30%)

MIL-On during active adaptive limit condition

Adaptive-Enabled

Closed Loop-Enabled

Circuit Description

The HO2S sensor is used to determine if the fuel flow to the engine is correct by measuring the oxygen content in the exhaust gas. The ECM uses this information to correct the fuel flow with the Closed Loop multiplier and the Adaptive multiplier. This fault sets if the Adaptive multiplier exceeds the limits of normal operation.

Diagnostic Aids

If any other DTCs are present, diagnose those first

Oxygen Sensor Wire Heated Oxygen sensor wires may be mis-routed and contacting the exhaust manifold.

Vacuum Leaks Large vacuum leaks and crankcase leaks can cause a lean exhaust condition at especially at light load.

Injectors System will be lean if an injector driver or driver circuit fails open. The system will also be lean if an injector fails in a closed manner or is dirty.

Fuel Pressure Low fuel pressure, faulty fuel injector or damaged fuel pump assembly can cause fuel system to run lean

Exhaust Leaks If there is an exhaust leak, outside air can be pulled into the exhaust and past the 02 sensor causing a false lean condition.

Fuel Quality Contaminated or spoiled fuel can cause the fuel system to be lean.

Ground Problem ECM grounds must be good battery or engine ground.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-79

DTC 241 Adaptive Lean Fault (High Limit Gasoline)

Step Action

1 • Perform the On-Board (OBD) System Check?

Are any other DTCs present?

Value(s) Yes No

Go to Step (3) Go to Step (2)

Go to Step (8) Go to Step (4)

2 Visually and physically check the following items:

• The air intake duct for being collapsed or restricted

• The air filter for being plugged

• The HO2S sensor installed securely and the wire leads not contacting the exhaust manifold or ignition wires

• ECM grounds for being clean and tight. Refer to

Section 1C Engine Electrical Power and Ground

Distribution

• Fuel System Diagnostics. Refer to Section 1B Fuel

System Diagnostics

Was a repair made?

3 • Diagnose any other DTC codes before proceeding with this chart.

Have any other DTC codes been detected, diagnosed and repaired?

4 • Key ON Engine running

• Back probe the HO2S sensor connector heater terminals D for negative and C for positive

• Using a DVOM check for voltage

• Do you have voltage?

5 • Key OFF

• Disconnect HO2S sensor wire harness connector

• Disconnect ECM wire harness connector

• Key ON

• Using a high impedance DVOM check for continuity between HO2S connector signal pin B and engine ground

Do you have voltage?

6 • Using a high impedance DVOM check for continuity between HO2S connector sensor ground pin A and

HO2S signal pin B

• Do you have continuity?

Battery voltage

7 • Replace HO2S sensor

Is the replacement complete?

Go to Step (8) Go to step (4)

Go to Step (5) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (8)

Go to Step (7)

-

1C4–80 Diagnostic Trouble Codes

8 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-241 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-81

1C4–82 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 242-Adaptive Rich Fault (low limit-gasoline)

- +

Sensor

Heater

B

DK GRN/ORN

55

A

BLK/LT GRN

49

D

BLK

C

PNK/DKGRN

HO2S

Sensor Ground

ECM

To System Power Relay

To Engine Ground

Conditions for Setting the DTC

Heated Oxygen Sensor

Functional Fault-Adaptive multiplier out of range (at limit of -30%)

MIL-On during active adaptive limit condition

Adaptive-Enabled

Closed Loop-Enabled

Circuit Description

The HO2S sensor is used to determine if the fuel flow to the engine is correct by measuring the oxygen content in the exhaust gas.

The ECM uses this information to correct the fuel flow with the Closed Loop multiplier and the Adaptive multiplier. This fault sets if the Adaptive multiplier exceeds the limits of normal operation.

Diagnostic Aids

Always diagnose any other ECM codes that are present before beginning this diagnostic procedure.

Fuel System The system will be rich if an injector fails in an open manner. High fuel pressure due to a faulty fuel regulator or obstructed fuel return line will cause the system to run rich.

Ignition noise open or poor ground circuit to or in the ignition system or ECM may cause EMI (Electromagnetic interference). This noise could be interpreted by the ECM as ignition pulses, and the sensed RPM becomes higher than the actual speed. The ECM then delivers too much fuel, causing the system to go rich.

TMAP Sensor A higher manifold pressure than normal can cause the system to go rich. Temporarily disconnecting the MAP Sensor will allow the ECM to set a default value for MAP.

IAT Sensor Check for a shifted sensor that could cause the ECM to sense lower than actual temperature of incoming air. This can cause a rich exhaust condition.

ECT Sensor Check for a skewed sensor that could cause the ECM to sense engine temperature colder than it actually is. This could also cause a rich exhaust condition.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-83

DTC 242 Adaptive Rich Fault (Low Limit Gasoline)

Step Action

1 • Perform the On-Board (OBD) System Check?

Are any other DTCs present?

Value(s) Yes No

Go to Step (3) Go to Step (2)

Go to Step (7) Go to Step (4)

2 Visually and physically check the following items:

• The air intake duct for being collapsed or restricted

• The air filter for being plugged

• The HO2S sensor installed securely and the wire leads not contacting the exhaust manifold or ignition wires

• ECM grounds for being clean and tight. Refer to

Section 1C Engine Electrical Power and Ground

Distribution

• Fuel System Diagnostics. Refer to Section 1B Fuel

System Diagnostics

Was a repair made?

3 • Diagnose any other DTC codes before proceeding with this chart.

Have any other DTC codes been detected, diagnosed and repaired?

4 • Key OFF

• Disconnect HO2S sensor wire harness connector

• Disconnect ECM wire harness connector

• Key ON

• Using a DVOM check for voltage at HO2S connector signal pin B and engine ground

Do you have voltage?

5 • Replace HO2S sensor

Is the replacement complete?

7 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-242 check for any stored codes.

Does the engine operate normally with no stored codes?

Go to Step (7) Go to step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (5)

Go to Step (7) -

System OK

Go to OBD

System Check

1C4–84 Diagnostic Trouble Codes

DTC 243-Adaptive Learn High (LPG)

1.6 liter Emission Certified GM Engine

- +

Sensor

Heater

B

DK GRN/ORN

55

A

BLK/LT GRN

49

D

BLK

C

PNK/DKGRN

HO2S

Sensor Ground

ECM

To System Power Relay

To Engine Ground

Conditions for Setting the DTC

Heated Oxygen Sensor

Check Condition- Engine Running

Fault Condition- Adaptive multiplier out of range (greater than 30%)

MIL- Disabled

Adaptive- Enabled

Closed Loop- Enabled

Circuit Description

The HO2S sensor is used to determine if the fuel flow to the engine is correct by measuring the oxygen content in the exhaust gas. The ECM uses this information to correct the fuel flow with the Closed Loop multiplier and Adaptive multiplier. This fault will set if the adaptive multiplier exceeds the limits of normal operation.

If any other DTCs are present, diagnose those first

Oxygen Sensor Wire Heated Oxygen sensor wires may be mis-routed and contacting the exhaust manifold.

Vacuum Leaks Large vacuum leaks and crankcase leaks can cause a lean exhaust condition at especially at light load.

Injectors System will be lean if an injector driver or driver circuit fails open. The system will also be lean if an injector fails in a closed manner or

1.6 liter Emission Certified GM Engine is dirty.

Diagnostic Trouble Codes 1C4-85

Fuel Pressure Low fuel pressure, faulty fuel injector or damaged fuel pump assembly can cause fuel system to run lean

Exhaust Leaks If there is an exhaust leak, outside air can be pulled into the exhaust and past the 02 sensor causing a false lean condition.

Fuel Quality Contaminated or spoiled fuel can cause the fuel system to be lean.

Ground Problem ECM grounds must be good battery or engine ground.

DTC 243 Adaptive Learn High (LPG)

Step Action

1 • Perform the On-Board (OBD) System Check?

Are any other DTCs present?

Value(s) Yes No

Go to Step (3) Go to Step (2)

Go to Step (7) Go to Step (4)

2 Visually and physically check the following items:

• The air intake duct for being collapsed or restricted

• The air filter for being plugged

• The HO2S sensor installed securely and the wire leads not contacting the exhaust manifold or ignition wires

• ECM grounds for being clean and tight. Refer to

Section 1C Engine Electrical Power and Ground

Distribution

• Fuel System Diagnostics. Refer to Section 1B Fuel

System Diagnostics

Was a repair made?

3 • Diagnose any other DTC codes before proceeding with this chart.

Have any other DTC codes been detected, diagnosed and repaired?

4 • Key ON Engine running

• Using a DVOM back probe the HO2S sensor connector heater circuit pin C for positive and D for negative. check for voltage

• Do you have voltage?

5 • Key OFF

• Disconnect HO2S sensor wire harness connector

• Disconnect ECM wire harness connector

• Key ON

• Using a DVOM check for voltage at HO2S connector signal pin B and engine ground

Do you have voltage?

6 • Replace HO2S sensor

Is the replacement complete?

Battery voltage

Go to Step (7) Go to step (4)

Go to Step (5) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (7) -

1C4–86 Diagnostic Trouble Codes

7 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-243 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-87

1C4–88 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 244-Adaptive Learn Low (LPG)

- +

Sensor

Heater

B

DK GRN/ORN

55

A

BLK/LT GRN

49

D

BLK

C

PNK/DKGRN

HO2S

Sensor Ground

ECM

To System Power Relay

To Engine Ground

Conditions for Setting the DTC

Heated Oxygen Sensor

Check Condition- Engine running

Fault Condition- Adaptive multiplier out of range (at limit of -30%)

MIL-Disabled

Adaptive- Enabled

Closed Loop- Enabled

Circuit Description

The HO2S sensor is used to determine if the fuel flow to the engine is correct by measuring the oxygen content in the exhaust gas. The ECM uses this information to correct the fuel flow with the Closed Loop multiplier and Adaptive multiplier. This fault will set if the adaptive multiplier exceeds the limits of normal operation.

Diagnostic Aids

Always diagnose any other ECM codes that are present before beginning this diagnostic procedure.

Fuel System High secondary fuel pressure will cause the system to run rich. A worn fuel mixer, faulty PTV (pressure trim valve) or

FTV (fuel trim valve) can also cause the system to run rich.

Fuel Quality A drastic variation in fuel quality (very high butane content) may cause the system to run rich. Be sure that the specified

HD-5 or HD-10 motor fuel grade propane is used.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-89

DTC 244 Adaptive Learn Low (LPG)

Step Action

1 • Perform the On-Board (OBD) System Check?

Are any other DTCs present?

Value(s) Yes No

Go to Step (3) Go to Step (2)

Go to Step (7) Go to Step (4)

2 Visually and physically check the following items:

• The air intake duct for being collapsed or restricted

• The air filter for being plugged

• ECM grounds for being clean and tight. Refer to

Section 1C Engine Electrical Power and Ground

Distribution

• Fuel System Diagnostics. Refer to Section 1B Fuel

System Diagnostics

Was a repair made?

3 • Diagnose any other DTC codes before proceeding with this chart.

Have any other DTC codes been detected, diagnosed and repaired?

4 • Key OFF

• Disconnect HO2S sensor wire harness connector

• Disconnect ECM wire harness connector

• Key ON

• Using a DVOM check for voltage at HO2S connector signal pin B and engine ground

Do you have voltage?

5 • Replace HO2S sensor

Is the replacement complete?

7 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-244 check for any stored codes.

Does the engine operate normally with no stored codes?

Go to Step (7) Go to step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (5)

Go to Step (7) -

System OK

Go to OBD

System Check

1C4–90 Diagnostic Trouble Codes

DTC 261-System Voltage Low

GROUND

BLK

BLK

19

20

ECM

1.6 liter Emission Certified GM Engine

VBAT

RED/TAN

RED/TAN

22

23

Conditions for Setting the DTC

System Voltage to ECM

Check Condition-Key on and RPM greater than 1500

Fault Condition-Battery voltage at ECM less than 9.0 volts continuously for 5 secondsV

MIL-On for active fault and for 10 seconds after active fault

Adaptive-Disabled for remainder of key on cycle

Closed Loop-Enabled

Circuit Description

The battery voltage powers the ECM and must be measured to correctly operate injector drivers, fuel trim valves and ignition coils. This fault will set if the ECM detects system voltage less than 9.0 for 5 seconds or longer while the alternator should be charging. The adaptive learn is disabled.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-91

DTC 261- System Voltage Low

Step Action

1 Did you perform the On-Board (OBD) System Check?

2

Value(s)

-

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3)

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Does DST display system voltage greater than 9.0 volts?

Intermittent problem

Go to Engine

Electrical

Intermittent section

3 • Check battery condition

Is it OK?

4 • Check charging system

Is it Ok?

5 • Back probe ECM connector pins 22 and 23

• Measure voltage with DVOM between each pin and engine ground

Is the voltage greater than 9.0 volts?

-

-

-

-

-

Go to Step (4) Replace Battery

Go to Step (5) Repair charging

System

Repair ECM

Ground circuit.

Go to Power and Ground section in engine Electrical

Repair ECM power circuit.

Go to Power and Ground section in engine Electrical

Go to Step (8)

Go to Step (6)

Go to step (7)

-

6

• Back probe ECM connector pins 19 and 20

• Measure voltage with DVOM between each pin and battery voltage

Is the voltage greater than 9.0 volts?

7 Replace ECM

Is the replacement complete?

8 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-261 check for any stored codes.

Does the engine operate normally with no stored codes?

System OK Go to OBD

System Check

1C4–92 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 262-System Voltage High

ECM

GROUND

BLK

BLK

19

20

VBAT

Conditions for Setting the DTC

RED/TAN

RED/TAN

22

23

System Voltage to ECM

Check Condition-Cranking or Running

Fault Condition-Switched battery voltage at ECM greater than 18 volts for 3 seconds

MIL-On for active fault and for 5 seconds after active fault

Adaptive-Disabled for remainder of key on cycle

Closed Loop-Enabled

Circuit Description

The battery voltage powers the ECM and must be measured to correctly operate injector drivers, trim valves and ignition coils. This fault will set if the ECM detects voltage greater than 18 volts for 3 seconds at anytime the engine is cranking or running. The adaptive learn is disabled. The ECM will shut down with internal protection if the system voltage exceeds 26 volts. The ECM fuse will then open.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-93

DTC 262- System Voltage High

Step Action

1 Did you perform the On-Board (OBD) System Check?

2

Value(s)

-

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3)

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Run engine greater than 1500 rpm.

Intermittent problem

Go to Engine

Electrical

Intermittent section

Does DST display system voltage less than 18 volts?

-

Go to Step (4) Go to Step (5)

3 • Check voltage at battery terminals with DVOM with engine speed greater than 1500 rpm

Is it greater than 18 volts?

4 • Repair the charging system

Has the charging system been repaired?

5 • Replace ECM

Is the replacement complete?

6 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-262 check for any stored codes.

Does the engine operate normally with no stored codes?

-

-

Go to Step (6)

Go to Step (6)

System OK

-

-

Go to OBD

System Check

1C4–94 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 411- Injector Driver 1 Open

ORN/LT BLU

C003

A

ORN/BLU

18

ECM

Injector Power

Inj 1

BRN /LT BLU

BRN/LT BLU

Inj 4

BRN/LT GRN

Inj 2

BRN/LT GRN

Inj 3

B

C

BRN/BLU

BRN/GRN

16

Injector Driver 1

17

Injector Driver 2

REV A

Conditions for Setting the DTC

Injector coil open or driver circuit short

Check Condition-Key on and engine running

Fault Condition-Battery voltage at ECM greater than 9 volts and injector low-side less than 4 volts for 10 injector firings

MIL-On for active fault and for 5 seconds after active fault

Adaptive-Disabled for remainder of key-on cycle

Closed Loop-Disabled during active fault

Circuit Description

Injector driver number one drives the number one and four cylinder injectors.

This fault will set if the ECM detects low feedback voltage on the internal injector while the injector drive circuit is in the off-state and battery voltage is greater than 9 volts.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-95

DTC 411-Injector Driver 1 Open

Step

1

2

Action

Did you perform the On-Board (OBD) System Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Clear System DTC 411

Does DTC 411 reset with the engine idling?

Value(s)

_

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to step (3) Intermittent problem

Go to

Intermittent section

3

3.5 Ohms or less

Go to step (5)

Go to step (4)

Key Off

Disconnect the wire harness connector at the number 1and number 4 injector.

• Using a high impedance DVOM, measure the resistance between the (2) pins on each injector

Does the DVOM display a resistance value of 3.5

Ohms or less?

4

Go to Step (12) _

5

6

7

• Replace the Fuel Injector that measures more than 3.5 Ohms.

Is the replacement complete?

• Measure the resistance at the injector connector driver BRN/LT BLU wire and battery ground.

Does the DVOM display a resistance of 5.0 Ohms or less?

__

• Disconnect ECM connector C001

• Measure the resistance between the injector driver wire BRN/LT BLU and battery ground.

Does the DVOM display a resistance of 5.0 Ohms or less?

5.0 Ohms

• Disconnect ECM wire harness connector C001

• Using a DVOM measure the resistance between the injector connector driver wire BRN/LT BLU and

ECM connector pin 16

• Does the DVOM display a resistance of 5.0 Ohms or less between them?

5.0 Ohms

Go to Step (6) Go to step (10)

Repair the shorted injector driver circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (10)

Go to Step (8)

Go to Step (9)

1C4–96 Diagnostic Trouble Codes

8

• Check the injector connector and ECM connector terminals for damage, corrosion or contamination.

Any problems found?

9 • Check continuity through the injector harness connector pin B

Do you have continuity?

10

11

12

• Back probe the ECM connector C001 pin 49

• Measure the resistance between the injector driver BRN/LT BLU wire and ECM pin 49

Does the DVOM display a resistance of 5.0 Ohms or less?

• Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-411 check for any stored codes.

• Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

Go to step (11)

Repair the open injector driver circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Intermittent problem

Go to

Intermittent section

Go to Step (11)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (7)

_

Go to step (12)

System OK

_

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-97

1C4–98 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

DTC 412- Injector Driver 1 Shorted

ORN/LT BLU

C003

A

ORN/BLU

18

ECM

Injector Power

BRN/BLU

Inj 1

BRN /LT BLU

BRN/LT BLU

Inj 4

BRN/LT GRN

Inj 2

BRN/LT GRN

Inj 3

B

C

BRN/GRN

16

Injector Driver 1

17

Injector Driver 2

REV A

Conditions for Setting the DTC

• Injector coil shorted

• Check Condition-Key on and engine running

• Fault Condition-Battery voltage at ECM less than 16 volts and injector low-side greater than 4 volts for 10 injector firings

• MIL-On during active fault and for 5 seconds after active fault

• Adaptive-Disabled for remainder of key-on cycle

• Closed Loop-Disabled during active fault

Circuit Description

Injector driver number one drives the number one and four cylinder injectors.

This fault will set if the ECM detects 10 injector firings with the internal driver sense voltage greater than 4 volts while the injector is in the on-state and battery voltage is less than 16 volts.

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-99

DTC 412-Injector Driver 1 Shorted

7

2

3

4

5

6

Did you perform the On-Board (OBD) System

Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Clear System DTC 412

Does DTC 412 reset with the engine idling?

Key Off

Disconnect the wire harness connector at the number 1and number 4 injector.

• Using a high impedance DVOM, measure the resistance between the (2) pins on each injector

Does the DVOM display a resistance value of 1.5

Ohms or more?

• Replace the Fuel Injector

• Disconnect ECM wire harness connector

• Key ON

• Using a DVOM check for voltage between the

ECM connector pin16 and engine ground

Does the DVOM display a voltage?

• Replace Fuel Injector

Is the replacement complete?

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

Is the replacement complete?

_

Go to OBD

System Check

Go to step (3)

Section problem

Go to

Intermittent section

1.5 Ohms or greater

Go to step (5)

Go to step (4)

Go to Step (8)

Repair the shorted to voltage injector driver circuit as necessary. Refer to

Wiring Repairs in Engine

_

Go to Step (6)

-

Go to step (9) _

1C4–100 Diagnostic Trouble Codes

8 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC412 check for any stored codes.

• Does the vehicle engine normally with no stored codes?

9 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC412 check for any stored codes.

• Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to Step (7)

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-101

1C4–102 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-103

DTC 413-Injector Driver 2 Open

Step

1

2

Action

Did you perform the On-Board (OBD) System Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Clear System DTC 413

Does DTC 413 reset with the engine idling?

Value(s)

_

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to step (3) Intermittent problem

Go to

Intermittent section

3

3.5 Ohms or less

Go to step (5)

Go to step (4)

Key Off

Disconnect the wire harness connector at the number 2 and number 3 injector.

• Using a high impedance DVOM, measure the resistance between the (2) pins on each injector

Does the DVOM display a resistance value of 3.5

Ohms or less?

4

Go to Step (12) _

5

6

7

• Replace the Fuel Injector that measures more than 3.5 Ohms.

Is the replacement complete?

• Measure the resistance at the injector connector driver BRN/GRN wire and battery ground.

Does the DVOM display a resistance of 5.0 Ohms or less?

__

• Disconnect ECM connector C001

• Measure the resistance between the injector driver wire BRN/GRN and battery ground.

Does the DVOM display a resistance of 5.0 Ohms or less?

5.0 Ohms

• Disconnect ECM wire harness connector C001

• Using a DVOM measure the resistance between the injector connector driver wire BRN/GRN and

ECM connector pin 17

• Does the DVOM display a resistance of 5.0 Ohms or less between them?

5.0 Ohms

Go to Step (6) Go to step (10)

Repair the shorted injector driver circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (10)

Go to Step (8)

Go to Step (9)

1C4–104 Diagnostic Trouble Codes

8

• Check the injector connector and ECM connector terminals for damage, corrosion or contamination.

Any problems found?

9 • Check continuity through the injector harness connector pin C

Do you have continuity?

10

11

12

• Back probe the ECM connector C001 pin 49

• Measure the resistance between the injector driver BRN/GRN wire and ECM pin 49

Does the DVOM display a resistance of 5.0 Ohms or less?

• Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-413 check for any stored codes.

• Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

Go to step (11)

Repair the open injector driver circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Intermittent problem

Go to

Intermittent section

Go to Step (11)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (7)

_

Go to step (12)

System OK

_

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-105

1C4–106 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-107

DTC 414-Injector Driver 2 Shorted

2

3

4

5

6

Did you perform the On-Board (OBD) System

Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

• Clear System DTC 414

Does DTC 414 reset with the engine idling?

Key Off

Disconnect the wire harness connector at the number 2 and number 3 injector.

• Using a high impedance DVOM, measure the resistance between the (2) pins on each injector

Does the DVOM display a resistance value of 2.0

Ohms or more?

• Replace the Fuel Injector

• Disconnect ECM wire harness connector

• Key ON

• Using a DVOM check for voltage between the

ECM connector pin17 and engine ground

Does the DVOM display a voltage?

Go to OBD

System Check

Go to step (3)

Section problem

Go to

Intermittent section

Go to step (5)

Go to step (4)

Go to Step (8)

Repair the shorted to voltage injector driver circuit as necessary. Refer to

Wiring Repairs in Engine

_

Go to Step (6)

-

7

• Replace Fuel Injector

Is the replacement complete?

Replace ECM. Refer to ECM replacement in the

Engine Controls Section.

Is the replacement complete?

_

Go to step (9) _

1C4–108 Diagnostic Trouble Codes

8 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC412 check for any stored codes.

• Does the vehicle engine normally with no stored codes?

9 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC412 check for any stored codes.

• Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to Step (7)

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-109

1C4–110 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

DTC 511 COP Failure

Diagnostic Trouble Codes 1C4-111

Step

1

2

3

4

Action

Did you perform the On-Board (OBD) System Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

• Clear system fault code

Does DTC 511 reset with the engine idling?

• Check all ECM power and ground circuits. Refer to power and ground distribution in engine electrical section.

Are the power and ground circuits Ok?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4) -

5

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-511 check for any stored codes.

Does the engine operate normally with no stored codes?

System OK Go to OBD

System Check

1C4–112 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-113

DTC 512 Invalid Interrupt

Step

1

2

3

4

Action

Did you perform the On-Board (OBD) System Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

• Clear system fault code

Does DTC 512 reset with the engine idling?

• Check all ECM power and ground circuits. Refer to power and ground distribution in engine electrical section.

Are the power and ground circuits Ok?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4) -

5

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-512 check for any stored codes.

Does the engine operate normally with no stored codes?

System OK Go to OBD

System Check

1C4–114 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

Step

1

2

3

4

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

• Clear system fault code

Does DTC 513 reset with the engine idling?

• Check all ECM power and ground circuits. Refer to power and ground distribution in engine electrical section.

Are the power and ground circuits Ok?

Diagnostic Trouble Codes 1C4-115

DTC 513 A/D Loss

Action

Did you perform the On-Board (OBD) System Check?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4) -

5

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-513 check for any stored codes.

Does the engine normally with no stored codes?

System OK Go to OBD

System Check

1C4–116 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

Step

1

2

3

4

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

• Clear system fault code

Does DTC 514 reset with the engine idling?

• Check all ECM power and ground circuits. Refer to power and ground distribution in engine electrical section.

Are the power and ground circuits Ok?

Diagnostic Trouble Codes 1C4-117

DTC 514 RTI 1 Loss

Action

Did you perform the On-Board (OBD) System Check?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4) -

5

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-514 check for any stored codes.

Does the engine operate normally with no stored codes?

System OK Go to OBD

System Check

1C4–118 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-119

DTC 515 Flash Checksum Invalid

Step

1

2

3

4

Action

Did you perform the On-Board (OBD) System Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

• Clear system fault code

Does DTC 515 reset with the engine idling?

• Check all ECM power and ground circuits. Refer to power and ground distribution in engine electrical section.

Are the power and ground circuits Ok?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4) -

5

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-515 check for any stored codes.

Does the engine operate normally with no stored codes?

System OK Go to OBD

System Check

1C4–120 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

DTC 516 Ram Failure

Diagnostic Trouble Codes 1C4-121

Step

1

2

3

4

Action

Did you perform the On-Board (OBD) System Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

• Clear system fault code

Does DTC 516 reset with the engine idling?

• Check all ECM power and ground circuits. Refer to power and ground distribution in engine electrical section.

Are the power and ground circuits Ok?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4) -

5

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-516 check for any stored codes.

Does the engine operate normally with no stored codes?

System OK Go to OBD

System Check

1C4–122 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-123

DTC 531 External 5V Reference Lower Than Expected

Step

1

2

3

Action

Did you perform the On-Board (OBD) System Check?

• Key ON, Engine Running

• DST (Diagnostic Scan Tool) connected in

System Fault Mode

Does DST display DTC 531?

• Key OFF

• Disconnect ECM connector

• Using DVOM check for continuity between ECM

5 volt reference LT GRN/R pin 50 and engine ground

Do you have continuity?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (5) Go to Step (4)

4

5

Go to Step (7)

Go to Step (6) -

-

6

• Replace ECM

Is the replacement complete?

• While monitoring DVOM for continuity between

ECM 5 volt reference and engine ground disconnect each sensor (below) one at a time to find the shorted 5 volt reference. When continuity to ground is lost the last sensor disconnected is the area of suspicion. Inspect 5volt reference supply wire leads for shorts before replacing the sensor.

• IAT

• ECT/CHT

• TMAP

• FPP

• TPS 1

• TPS 2

• Crankshaft Sensor

• Camshaft Sensor

While disconnecting each sensor one at a time did you loose continuity?

• Replace Sensor

Is the replacement complete?

Go to step (7) -

1C4–124 Diagnostic Trouble Codes

7 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-531 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-125

1C4–126 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-127

DTC 532 External 5V Reference Higher Than Expected

Step

1

2

3

Action

Did you perform the On-Board (OBD) System Check?

• Key ON, Engine running

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Does DST display DTC 532?

• Check all ECM ground connections

Refer to Engine electrical power and ground distribution.

Are the ground connections Ok?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

4 • Key OFF

• Disconnect ECM connector

• Key ON

• Using DVOM check for Voltage between ECM harness wire LT GRN/R pin 50 and engine ground

Do you have voltage?

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (5)

5

6

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-532 check for any stored codes.

Does the vehicle engine normally with no stored codes?

Go to Step (6)

System OK

-

Go to OBD

System Check

1C4–128 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

Step

1

2

3

4

DTC 555 RTI 2 Loss

Diagnostic Trouble Codes 1C4-129

Action

Did you perform the On-Board (OBD) System Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

• Clear system fault code

Does DTC 555 reset with the engine idling?

• Check all ECM power and ground circuits. Refer to power and ground distribution in engine electrical section.

Are the power and ground circuits Ok?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4) -

5

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-555 check for any stored codes.

Does the engine operate normally with no stored codes?

System OK Go to OBD

System Check

1C4–130 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

Step

1

2

3

4

DTC 556 RTI 3 Loss

Diagnostic Trouble Codes 1C4-131

Action

Did you perform the On-Board (OBD) System Check?

• Key On, Engine Running

• DST (Diagnostic Scan Tool) connected in

• System Data Mode

• Clear system fault code

Does DTC 555 reset with the engine idling?

• Check all ECM power and ground circuits. Refer to power and ground distribution in engine electrical section.

Are the power and ground circuits Ok?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (4) -

5

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-556 check for any stored codes.

Does the engine operate normally with no stored codes?

System OK Go to OBD

System Check

1C4–132 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-133

DTC 611 FPP Voltage High

2

3

Did you perform the On-Board (OBD) System

Check?

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Does the DST display FPP voltage of 4.8 volts or

Slowly increase FPP while observing FPP voltage

Does DST FPP voltage ever exceed 4.8 volts?

Go to OBD

System Check

Go to Step (8)

Section

4

5

6

7

8

• Key OFF

• Disconnect FPP sensor connector

• Inspect connector and wire terminals for damage, corrosion or contamination

Any problems found?

• Disconnect ECM connector C001

• Check continuity between FPP sensor connector ground pin B and ECM connector FPP sensor ground pin 49

Do have continuity between them?

• Key ON

• Using a DVOM check for voltage at ECM wire harness connector FPP signal pin 38 and ECM sensor ground terminal pin 49

Do you have voltage between them?

• Using a DVOM check for voltage at ECM wire harness connector between ECM FPP signal pin

38 and engine ground

Do you have voltage between them?

• Key OFF

• Disconnect FPP sensor from wire harness

• Key ON

Go to step (4) Intermittent problem

Go to

Intermittent

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (7)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (11)

Intermittent problem

Go to

Intermittent section

Go to Step (9)

9

• Using a DVOM check for voltage between the

ECM FPP signal pin 38 and engine ground

Do you have voltage between them?

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (15)

Go to Step (10)

-

Go to Step (12) Go to Step (14)

10 • Replace ECM

11

Is the replacement complete?

with a test light connected to battery voltage

12

Does the test light come on?

• Disconnect ECM wire harness connector

• Inspect the ECM wire harness connector terminals for damage, corrosion or contamination

Did you find a problem?

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to step (13)

1C4–134 Diagnostic Trouble Codes

13 • Replace FPP sensor

14

Is the replacement complete?

• Disconnect ECM connector

• Check continuity between FPP sensor connector ground pin B and ECM connector FPP sensor ground pin 49

15

Do have continuity between them?

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-611 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

Go to step (15) -

Go to Step (10)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-135

1C4–136 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-137

DTC 612 FPP Voltage Low

2

3

Did you perform the On-Board (OBD) System

Check?

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Does the DST display FPP voltage of 0.2 volts or less

Slowly depress FP while observing FPP voltage

Does DST FPP voltage ever drop below 0.2 volts?

Go to OBD

System Check

Go to Step (7)

Section

4

5

6

7

• Key OFF

• Disconnect FPP sensor connector

• Inspect connector and wire terminals for damage, corrosion or contamination

Any problems found?

• Key ON

• Using A DVOM check for voltage at the FPP sensor connector between 5 volt reference pin A and FPP sensor ground pin B

Do you have voltage between them?

• Replace FPP Sensor

5.0 Volts

Go to step (4) Intermittent problem

Go to

Intermittent

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

Repair the circuit as necessary. Refer to

Wiring Repairs

Go to Step (18)

in Engine

-

Go to Step (8) Go to Step (9)

8

• Disconnect FPP Sensor from wire harness

• Jumper 5 volt reference circuit pin A and FPP signal circuit pin C together

• Key ON

Does DST display FPP voltage of 4.8 volts or greater?

• Check FPP connector wire terminals for damage, corrosion or contamination?

Any problems found?

Repair the circuit as necessary. Refer to

Wiring Repairs

Go to Step (6)

in Engine

Go to Step (10) Go to Step (14)

9 • Probe FPP connector signal circuit pin C with a test light connected to battery voltage

10

Does the DST display FPP voltage of 4.8 volts or

• Key OFF

• Disconnect ECM wire harness connector

• Using a DVOM check for continuity between FPP sensor connector 5 volt reference pin A and ECM connector 5 volt reference pin 50

11

Do you have continuity between them?

5 volt reference pin 50 and engine ground

Do you have continuity between them?

Go to Step (11)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (12)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

1C4–138 Diagnostic Trouble Codes

12 • Using a DVOM check for continuity between

ECM connector 5 volt reference pin 50 and ECM sensor ground pin 49

Do you have continuity between them?

13 • Inspect FPP and ECM connector terminal terminals for damage, corrosion or contamination

Any problems found?

14 • Key OFF

• Disconnect ECM wire harness connector C001

• Using a DVOM check for continuity between FPP connector signal pin C and ECM connector FPP signal pin 38

15

Do you have continuity between them?

connector FPP signal pin 38 and engine ground

Do you have continuity?

16 • Using a DVOM check for continuity between

ECM FPP signal pin 38 and ECM connector FPP sensor ground pin 49

Do you have continuity between them?

17 • Replace ECM

18

Is the replacement complete?

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-612 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as neces-

Go to Step (13)

Go to Step (17)

sary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (15)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (18)

Go to Step (16)

Go to Step (13)

-

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-139

1C4–140 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-141

DTC 613 FPP Higher Than IVS Limit

Step

1

2

3

4

5

6

7

8

Action

Did you perform the On-Board (OBD) System Check?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Go to Step (7)

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Does the DST display IVS “idle” with the foot pedal fully depressed?

• Key OFF

• Disconnect foot pedal from harness

• Key ON

Does DST display IVS “idle”?

• Replace foot pedal

Is the replacement complete?

• Key OFF

• Disconnect ECM wire harness connector

• Using a DVOM check for continuity between IVS signal and engine ground

Do you have continuity between them?

• Replace ECM

Is the replacement complete?

• Depress foot pedal until DST reads FPP voltage between 1.1 and 1.3 volts

Does DST display IVS “idle”

• Remove all test equipment except the DST.

Go to Step (4) Go to Step (5)

Go to Step (8)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (8) -

-

Go to Step (6)

1.1 to 1.3 volts Go to Step (4) Intermittent

problem

Go to

Intermittent section

System OK

Go OBD

System Check

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-613 check for any stored codes.

Does the engine operate normally with no stored codes?

1C4–142 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-143

DTC 614 FPP Lower Than IVS Limit

Step

1

2

3

4

5

6

7

Action

Did you perform the On-Board (OBD) System Check?

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Does the DST display IVS “OFF IDLE” with the foot pedal in the idle position?

• Key OFF

• Jumper IVS signal and IVS ground together at wire harness connector

• Key ON

Does DST display IVS “ON”

• Replace Foot Pedal

Is the replacement complete?

• Key OFF

• Disconnect ECM wire harness connector

• Using a DVOM check for continuity between IVS signal and engine ground

Do you have continuity?

• Replace ECM

Is the replacement complete?

• Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-614 check for any stored codes.

Does the engine operate normally with no stored codes?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to step (4) Go to Step (5)

Go to Step (7)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (7)

Go to Step (6)

-

-

System OK

Go OBD

System Check

1C4–144 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-145

DTC 631 TPS 1 Signal Voltage High

2

3

4

Did you perform the On-Board (OBD) System

Check?

• Key ON, Engine OFF

DST (Diagnostic Scan Tool) connected

Does the DST display TPS 1 voltage of 4.8 volts or greater with the throttle closed

Slowly depress Foot Pedal while observing TPS 1 voltage

Does TPS 1 voltage ever exceed 4.8 volts?

• Key OFF

• Disconnect TPS 1 electrical connector

• Key ON

Go to OBD

System Check

Go to Step (4)

Section

Go to Step (4) Intermittent problem

Go to

Intermittent

Go to Step (7)

section

5

• Disconnect ECM wire harness connector

• Key ON

• Using a DVOM check for voltage between TPS 1 signal at the ECM connector pin 53 and engine ground

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

6

7

8

• Back probe sensor ground circuit at the ECM side of the wire harness pin 49 with a test light connected to battery voltage

• Inspect the TPS 1 electrical connector terminals for damage, corrosion or contamination

Did you find a problem?

Go to Step (11) -

Go to Step (8) Go to Step (10)

9 • Replace TPS 1sensor

10

Is the replacement complete?

• Disconnect ECM connector

• Using a DVOM check for continuity between the

TPS 1 connector sensor ground pin B and ECM connector TPS 1 sensor ground pin 49

Do have continuity between them?

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (11)

Go to Step (9)

-

Go to Step (6)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

1C4–146 Diagnostic Trouble Codes

11 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-631 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-147

1C4–148 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-149

DTC 632 TPS 1 Signal Voltage Low

2

3

4

Did you perform the On-Board (OBD) System

Check?

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

DBW (Drive by Wire) throttle test mode

Does the DST display TPS 1 voltage of 0.2 volts or less with the throttle closed

Slowly depress Foot Pedal while observing TPS 1 voltage

Does TPS 1 voltage ever fall below 0.2 volts?

Go to OBD

System Check

Go to Step (4)

Section

Go to Step (4) Intermittent problem

Go to

Intermittent

Go to Step (7)

section

5

6

7

8

• Key OFF

• Disconnect the TPS 1 electrical connector

• Jumper the 5 volt reference circuit pin A and

TPS 1 signal circuit pin C together at the throttle connector

• Key ON

Does DST display TPS 1voltage of 4.0 volts or

• Key OFF

• Disconnect ECM wire harness connector

Using a DVOM check continuity between TPS 1 connector signal pin C and ECM connector TPS 1 signal pin 53

• Inspect the throttle wire harness connector terminals for damage, corrosion or contamination

Did you find a problem?

• Replace the TPS 1

Is the replacement complete?

Go to Step (6 ) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (9) -

Go to Step (8)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (9) -

1C4–150 Diagnostic Trouble Codes

9 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-632 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-151

1C4–152 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-153

DTC 633 TPS 2 Signal Voltage High

Step

1

2

Action

Did you perform the On-Board (OBD) System Check?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (4) Go to Step (3)

3

4

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

DBW (Drive by Wire) throttle test mode

Does the DST display TPS 2 voltage of 4.8 volts or greater with the throttle closed

• Slowly depress Foot Pedal while observing TPS 2 voltage

Does TPS 2 voltage ever exceed 4.8 volts?

Go to Step (4) Intermittent problem

Go to

Intermittent section

Go to Step (7) Go to Step (5)

5

• Key OFF

• Disconnect electronic throttle connector

• Key ON

Does DST display TPS 2 voltage less than 0.2 volts?

• Key OFF

• Disconnect ECM wire harness connector C001

• Key ON

• Using a DVOM check for voltage between electronic throttle connector TPS 2 signal pin 5 and engine ground

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (6)

6

7

8

Do you have voltage?

• Replace ECM

Is the replacement complete?

• Back probe sensor ground circuit at the ECM side of the wire harness pin 49 with a test light connected to battery voltage

Does the test light come on?

• Inspect the electronic throttle wire harness connector and terminals for damage, corrosion or contamination

Did you find a problem?

Go to Step (11) -

Go to Step (8) Go to Step (10)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (11)

Go to Step (9)

-

9 • Replace electronic throttle

Is the replacement complete?

10 • Key OFF

• Disconnect ECM connector

• Using a DVOM check for continuity between throttle connector sensor ground pin 2 and ECM connector sensor ground pin 49

Do have continuity between them?

Go to Step (6) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

1C4–154 Diagnostic Trouble Codes

11 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-633 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-155

1C4–156 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-157

DTC 634 TPS 2 Signal Voltage Low

2

3

4

Did you perform the On-Board (OBD) System

Check?

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

DBW (Drive by Wire) throttle test mode

Does the DST display TPS 2 voltage of 0.2 volts or less with the throttle closed

Slowly depress Foot Pedal while observing TPS 2 voltage

Does TPS 2 voltage ever fall below 0.2 volts?

Go to OBD

System Check

Go to Step (4)

Section

Go to Step (4) Intermittent problem

Go to

Intermittent

Go to Step (7)

section

5

6

7

8

• Key OFF

• Disconnect electronic throttle connector

• Jumper the 5 volt reference circuit pin 3 and TPS

2 signal pin 5 together at the throttle connector

• Key ON

Does DST display TPS 2 voltage of 4.0 volts or

• Key OFF

• Disconnect ECM wire harness connector

Using a DVOM check continuity between electronic throttle TPS 2 signal pin 5 and ECM connector TPS 2 signal pin 54

• Inspect the electronic throttle wire harness connector and terminals for damage, corrosion or contamination

Did you find a problem?

• Replace throttle

Is the replacement complete?

Go to Step (6 ) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (9) -

Go to Step (8)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (9) -

1C4–158 Diagnostic Trouble Codes

9 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-634 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-159

1C4–160 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-161

DTC 634 TPS 2 Signal Voltage Low

2

3

4

Did you perform the On-Board (OBD) System

Check?

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

DBW (Drive by Wire) throttle test mode

Does the DST display TPS 2 voltage of 0.2 volts or less with the throttle closed

Slowly depress Foot Pedal while observing TPS 2 voltage

Does TPS 2 voltage ever fall below 0.2 volts?

Go to OBD

System Check

Go to Step (4)

Section

Go to Step (4) Intermittent problem

Go to

Intermittent

Go to Step (7)

section

5

6

7

8

• Key OFF

• Disconnect electronic throttle connector

• Jumper the 5 volt reference circuit pin 3 and TPS

2 signal pin 5 together at the throttle connector

• Key ON

Does DST display TPS 2 voltage of 4.0 volts or

• Key OFF

• Disconnect ECM wire harness connector

Using a DVOM check continuity between electronic throttle TPS 2 signal pin 5 and ECM connector TPS 2 signal pin 54

• Inspect the electronic throttle wire harness connector and terminals for damage, corrosion or contamination

Did you find a problem?

• Replace throttle

Is the replacement complete?

Go to Step (6 ) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (9) -

Go to Step (8)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (9) -

1C4–162 Diagnostic Trouble Codes

9 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-634 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-163

1C4–164 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-165

DTC 636 TPS 1 Lower Than TPS 2

2

3

4

5

6

7

8

9

Did you perform the On-Board (OBD) System

Check?

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

System Data Mode

Does the DST display more than a 20% difference

Key OFF

Disconnect wiring harness connector from the electronic throttle

Key ON

Change DST mode to DBW (drive by wire) test mode

Is the voltage for TPS 1 and TPS 2 less than 0.1 volts?

• Key OFF

• Disconnect ECM wiring harness connector C001

• Key ON

• Using a DVOM check for voltage at the ECM connector between TPS 1 signal pin 53 or TPS

2 signal pin 54 (the one that is over 0.1 volts) and engine ground

• Jumper TPS 1 signal pin 6 and TPS 2 signal pin 5 to the 5 volt reference at the throttle connector pin

3

Does DST display TPS 1 and TPS 2 voltage over

4.95 volts

• Inspect wire terminals at throttle connector for damage corrosion or contamination

Any problems found?

• Replace Throttle

• Disconnect ECM wire harness connector C001 from ECM

Using a DVOM check for continuity between throttle connector TPS 1 signal pin 6 and ECM connector

TPS 1 signal pin 53

• Using a DVOM check for continuity between throttle connector TPS 2 signal pin 5 and ECM connector TPS 2 signal pin 54

Do you have continuity between them?

Go to OBD

System Check

Go to Step (3)

Section problem

Go to

Intermittent section

Go to Step (5) Go to Step (4)

Repair the TPS

1 or TPS 2 circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (13)

Go to Step (6) Go to Step (8)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (14)

Go to Step (7)

-

Go to Step (9)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (10)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

1C4–166 Diagnostic Trouble Codes

10 • Using a DVOM check for continuity between throttle connector TPS 1 signal pin 6 and engine ground

Do you have continuity?

11 • Using a DVOM check for continuity between throttle connector TPS 2 signal pin 5 and engine ground

Do you have continuity?

12 • Inspect ECM connector terminals for damage corrosion or contamination.

Any problems found?

13 • Replace ECM

14

Is the replacement complete?

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-636 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Go to Step (14)

Go to Step (11)

Go to Step (12)

Go to Step (13)

-

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-167

1C4–168 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-169

DTC 637 Throttle Unable to Open

Step

1

2

3

4

5

6

7

Action

Did you perform the On-Board (OBD) System Check?

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

DBW (Drive By Wire) test mode

• Depress Foot Pedal until theThrottle Command is

63%-68%

Is the TPS voltage less than 2.0 volts?

• Key OFF

• Disconnect wire harness connector from throttle

• Probe TPS 1 signal circuit with test light connected to battery voltage

• Key ON

Is TPS voltage 4.0 volts or greater?

• Check throttle bore for foreign object

Did you find a problem?

• Remove the foreign object

Has the object been removed?

• Check throttle connector terminals for damage corrosion or contamination

Did you find a problem?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (4) Go to Step (8)

Go to Step (5) Go to step (6)

Go to Step (11)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (11) -

-

Go to Step (7)

8

9

• Replace throttle

Is the replacement complete?

• Key OFF

• Disconnect ECM wire harness connector

• Using a DVOM check for continuity between throttle connector TPS 1 signal terminal and ECM

TPS 1 signal terminal

Do you have continuity between them?

• Using a DVOM check for continuity between throttle connector TPS 1 signal and engine ground

Do you have continuity between them?

10 • Replace ECM

Is the replacement complete?

Go to Step (9)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (10)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to step (11) -

1C4–170 Diagnostic Trouble Codes

11 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-637 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-171

1C4–172 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-173

DTC 638 Throttle Unable to Close

Step

1

Action

Did you perform the On-Board (OBD) System Check?

2

3

4

5

6

• Key ON, Engine OFF

• DST (Diagnostic Scan Tool) connected in

DBW (Drive By Wire) test mode

• Depress Foot Pedal until theThrottle Command is between 63%-68%

Is the TPS 1 voltage greater than 2.0 volts?

• Key OFF

• Disconnect wire harness connector from throttle

• Probe TPS 1 signal circuit with test light connected to battery voltage

• Key ON

Does DST display TPS 1 voltage less than 0.2 volts

• Key OFF

• Disconnect ECM wire harness connector

• Key ON

• Using a DVOM check for voltage between throttle connector signal terminal and engine ground

Do you have voltage?

• Replace ECM

Is the replacement complete?

• Back probe sensor ground circuit at ECM connector with test light connected to battery voltage

Does the test light come on?

7

8

9

• Key OFF

• Disconnect ECM wire harness connector

• Using a DVOM check for continuity between throttle connector signal ground and ECM signal ground circuit terminals

Do you have continuity between them?

• Replace ECM

• Is the replacement complete?

• Check throttle for foreign object in bore

Did you find a foreign object in the bore?

10 • Remove foreign object

Is the removal complete?

11 • Inspect the throttle wire harness connector terminals for damage, corrosion or contamination

Did you find the problem?

12 • Replace throttle

Is the replacement complete?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Intermittent problem

Go to

Intermittent section

Go to Step (6) Go to Step (4)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (13)

Go to Step (5)

Go to Step (9) Go to Step (7)

Go to Step (8) Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (13) -

Go to Step (10) Go to Step (11)

Go to Step (13)

Repair the circuit as necessary. Refer to

Wiring Repairs in Engine

Electrical.

Go to Step (13) -

-

-

Go to Step (12)

1C4–174 Diagnostic Trouble Codes

13 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-638 check for any stored codes.

Does the engine operate normally with no stored codes?

1.6 liter Emission Certified GM Engine

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-175

1C4–176 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-177

DTC 651 Max Govern Speed Override

Step Action

1 Did you perform the On-Board (OBD) System Check?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Go to Step (4)

2 • Key ON, Engine OFF

• DST in Active Fault Mode

Are any other DTC codes present with DTC 651?

3 • Diagnose any other DTC codes before proceeding with this chart.

Have any other DTC codes been diagnosed and repaired?

4 • Check the Service Part Number on the ECM to ensure correct calibration is in use

Is the Service Part Number Correct?

5 • Replace ECM with correct Service Part Number

Is the replacement complete?

6 • Check the mechanical operation of the throttle

Is the mechanical operation of the throttle OK?

7 • Correct mechanical operation of the throttle. Refer to Engine & Component R&R Section 1E

Has the mechanical operation of the throttle been corrected?

8 • Check engine for large manifold vacuum leaks.

Refer to Fuel Systems Section 1B Symptom

Diagnostics

Did you find and correct the vacuum leak?

9 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-651 check for any stored codes.

Does the engine operate normally with no stored codes?

Go to step (4)

Go to Step (9)

Go to step (9)

-

Go to Step (6) Go to Step 5

-

Go to Step (8) Go to Step (7)

-

Go to Step (9) Go to OBD

System Check

Section

System OK

Go to OBD

System Check

1C4–178 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine

DTC 652 Fuel Rev Limit

Diagnostic Trouble Codes 1C4-179

Step Action

1 Did you perform the On-Board (OBD) System Check?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Go to Step (4)

2 • Key ON, Engine OFF

• DST in Active Fault Mode

Are any other DTC codes present with DTC 651?

3 • Diagnose any other DTC codes before proceeding with this chart.

Have any other DTC codes been diagnosed and repaired?

4 • Check the Service Part Number on the ECM to ensure correct calibration is in use

Is the Service Part Number Correct?

5 • Replace ECM with correct Service Part Number

Is the replacement complete?

6 • Check the mechanical operation of the throttle

Is the mechanical operation of the throttle OK?

7 • Correct mechanical operation of the throttle. Refer to Engine & Component R&R Section 1E

Has the mechanical operation of the throttle been corrected?

8 • Check engine for large manifold vacuum leaks.

Refer to Fuel Systems Section 1B Symptom

Diagnostics

Did you find and correct the vacuum leak?

9 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-652 check for any stored codes.

Does the engine operate normally with no stored codes?

Go to step (4)

Go to Step (9)

Go to step (9)

-

Go to Step (6) Go to Step 5

-

Go to Step (8) Go to Step (7)

-

Go to Step (9) Go to OBD

System Check

Section

System OK

Go to OBD

System Check

1C4–180 Diagnostic Trouble Codes 1.6 liter Emission Certified GM Engine

1.6 liter Emission Certified GM Engine Diagnostic Trouble Codes 1C4-181

DTC 653 Spark Rev Limit

Step Action

1 Did you perform the On-Board (OBD) System Check?

Value(s)

-

Yes

Go to Step (2)

No

Go to OBD

System Check

Section

Go to Step (3) Go to Step (4)

2 • Key ON, Engine OFF

• DST in Active Fault Mode

Are any other DTC codes present with DTC 651?

3 • Diagnose any other DTC codes before proceeding with this chart.

Have any other DTC codes been diagnosed and repaired?

4 • Check the Service Part Number on the ECM to ensure correct calibration is in use

Is the Service Part Number Correct?

5 • Replace ECM with correct Service Part Number

Is the replacement complete?

6 • Check the mechanical operation of the throttle

Is the mechanical operation of the throttle OK?

7 • Correct mechanical operation of the throttle. Refer to Engine & Component R&R Section 1E

Has the mechanical operation of the throttle been corrected?

8 • Check engine for large manifold vacuum leaks.

Refer to Fuel Systems Section 1B Symptom

Diagnostics

Did you find and correct the vacuum leak?

9 • Remove all test equipment except the DST.

• Connect any disconnected components, fuses, etc.

• Using the DST clear DTC information from the

ECM.

• Turn the ignition OFF and wait 30 seconds.

• Start the engine and operate the vehicle to full operating temperature

• Observe the MIL

• Observe engine performance and driveability

• After operating the engine within the test parameters of DTC-653 check for any stored codes.

Does the engine operate normally with no stored codes?

Go to step (4)

Go to Step (9)

Go to step (9)

-

Go to Step (6) Go to Step 5

-

Go to Step (8) Go to Step (7)

-

Go to Step (9) Go to OBD

System Check

Section

System OK

Go to OBD

System Check

1.6 liter Emission Certified GM Engine

SECTION 1E1

FUEL SYSTEM R&R

Fuel System 1E1-1

Low Pressure Lock-Off Replacement ......................................1E1-2

Pressure Trim Valve (PTV) SolenoidReplacement ..............1E1-4

Low Pressure Regulator (LPR) Replacement ........................1E1-4

Fuel Trim Valve (FTV) Solenoid Replacement .......................1E1-5

TMAP Sensor Repalcement ....................................................1E1-6

Mixer Raplacement ...................................................................1E1-7

Coolant Hose Repalcement ......................................................1E1-7

Vapor Hose Replacment ...........................................................1E1-7

Balance Line Hose Replacement ...........................................1E1-8

PTV Hose Replacement ............................................................1E1-8

FTV Hose Replacement ...........................................................1E1-8

Engine Control Module (ECM) Replacement .........................1E1-8

Heated Exhaust Gas Oxygen Sensor (HO2S) Repl. ............1E1-9

Three Way Catalytic Converter Muffler Replacement .........1E1-9

Go to Table of Contents

1E1-2 Fuel System

REPAIR INSTRUCTIONS

PROPANE FUEL SYSTEM PRESSURE

RELIEF

To relieve propane fuel system pressure:

1. Close the manual shut-off valve (MSV) on the propane fuel tank.

2. Start and run the vehicle until the engine stalls.

3. Turn the ignition switch OFF.

!

CAUTION

The propane fuel system operates at pressures up to 21.5 BAR (312 psi).

To minimize the risk of fire and personal injury, relieve the propane fuel system pressure (where applicable) before servicing the propane fuel system components.

Important

• Residual vapor pressure will be present in the fuel system. Ensure the work area is well ventilated before disconnecting any fuel line.

PROPANE FUEL SYSTEM LEAK TEST

!

CAUTION

Never use an open flame of any type to check for propane fuel system leaks.

Always inspect the propane fuel system for leaks after performing service. Check for leaks at the fittings of the serviced or replaced component. Use a commercially available liquid leak detector or an electronic leak detector. When using both methods, use the electronic leak detector first to avoid contamination by the liquid leak detector.

PROPANE FUEL FILTER REPLACEMENT

(FIGURE 2)

Removal Procedure

1. Relieve the propane fuel system pressure. Refer to

1.6 liter Emission Certified GM Engine

Propane Fuel System Pressure Relief.

2. Disconnect the negative battery cable.

3. Slow loosen the Filter housing retaining bolt and retain.

4. Pull the filter housing down from the Electric lock off assembly

5. Locate Filter magnet and retain

6. Remove the filter from the housing

7. Remove and discard the housing seal

8. Remove and discard the retaining bolt seal.

9. Remove and discard mounting plate to lock off o-ring seal

Installation Procedure

Important: Be sure to reinstall the filter magnet into the housing before installing new seal

1. Install the mounting plate to lock off o-ring seal

2. Install the retaining bolt seal

3. Install the housing seal

4. Drop the magnet into the bottom of the filter housing

5. Install the filter into the housing

6. Install the retaining bolt into the filter housing

7. Install the filter up to the bottom of the electric lock off

8. Tighten the filter retain bolt to specification

Tighten

12 Nm (106 in lbs).

9. Open manual shut-off valve.

Start the vehicle and leak check the propane fuel system at each serviced fitting Refer to Propane Fuel System Leak

Test..

LOW PRESSURE LOCK-OFF (LPL)

REPLACEMENT

(FIGURE 2)

Removal Procedure

1. Relieve the propane fuel system pressure. Refer to

Propane Fuel System Pressure Relief.

2. Disconnect the negative battery cable.

3. Disconnect the LPL electrical connector.

4. Remove and retain the two (2) LPL mounting bolts

5. Disconnect the LPG fuel line from the LPL inlet fitting.

6. Remove inlet fitting from filter housing

7. Unscrew the LPL from the LPR inlet fitting.

1.6 liter Emission Certified GM Engine Fuel System 1E1-3

FIGURE 1 LPG FUEL LOCK OFF AND FILTER

FIGURE 2 LOW PRESSURE LOCK OFF

1E1-4 Fuel System

Installation Procedure

Important

• Do not use Teflon tape on any fuel fitting. Use a liquid pipe thread sealant when installing fittings.

1. Apply pipe thread sealant to the LPR inlet fitting.

2. Install the LPL to the LPR. Tighten the LPL finger tight plus 1 to 2 turns and place the LPL in the correct position.

3. Tighten the two (2) LPL mounting bolts

Tighten

10 Nm (88 in lbs).

4. Install in reverse order of removal.

5. Tighten the fuel line fitting to

Tighten

27 Nm (20 ft lbs).

.

6. Start the vehicle and leak check the propane fuel system at each serviced fitting.

PRESSURE TRIM VALVE (PTV)

REPLACEMENT

(FIGURE 2)

1. Disconnect the PTV electrical connection.

2. Remove the vacuum hose from the PTV

3. Remove and retain the two (2) retaining bolts

4. Remove the PTV

1.6 liter Emission Certified GM Engine

LOW PRESSURE REGULATOR (LPR)

REPLACEMENT

(FIGURE 2)

Removal Procedure

1. Relieve the propane fuel system pressure. Refer to

Propane Fuel System Pressure Relief.

2. Disconnect the negative battery cable.

3. Clamp the coolant hoses to the LPR or drain the radiator.

4. Remove the LPL. Refer to Low Pressure Lock-off

Replacement.

5. Remove the PTV Refer to Pressure Trim Valve

Replacement

6. Disconnect the supply and return coolant lines from the

LPR.

7. Remove the retaining pin from the water inlet and outlet fittings and retain

8. Remove the coolant inlet and outlet fitting retaining pins and retain.

9. Remove the inlet and outlet fittings from the LPR

10. Disconnect the FTV supply line

11. Loosen the two LPR mounting plate bolts and retain

12. Lift LPR assembly and remove the two (2) LPR mounting bolts and spacers and retain

13. Loosen the fuel vapor hose clamp at the LPR fuel outlet fitting

14. Disconnect the fuel vapor hose from the LPR outlet fitting and remove the LPR.

15. Remove the retaining pin from the vapor outlet fitting and retain

16. Remove and retain the vapor outlet fitting from the LPR

17. Remove the LPR.

Installation Procedure

Important

• Apply a small amount of O-ring lubricant to the

PTV O-ring before installation

Installation Procedure

Important

• Do not use Teflon tape on any fuel fitting. Use a liquid pipe thread sealant when installing fittings.

• Lubricate the o-ring of the PTV before installing into the LPR

• Be sure to reinstall LPR mounting spacers

1. Install in reverse order

2. Tighten retaining bolts

Tighten

9 N•m (80 lb-in)

3. Start the vehicle.

1. Install the inlet and outlet water fitting and secure with retaining pin

2. Install vapor outlet fitting and secure with retaining pin

3. Insert the vapor hose to the fuel outlet fitting and place clamp

4. Install the FTV supply line and secure

1.6 liter Emission Certified GM Engine

5. Secure the LPR to the mounting bracket using the two (2) retaining bolts and spacers and tighten to specification

Tighten

14 Nm (10 ft lbs)..

6. Install LPR mounting bracket to the intake manifold using two (2) mounting bolts and tighten to specification

Tighten

14 Nm (10 ft lbs)..

7. Install the water inlet and outlet lines to the fittings and place clamps

8. Install the water inlet and outlet lines to the fittings and place clamps

9. Install LPL. Refer to Low Pressure Lock-off

Replacement.

10. Install the PTV Refer to Pressure Trim Valve

Replacement

11. Tighten fuel line fitting

Tighten

27 Nm (20 ft lbs).

Fuel System 1E1-5

12. Replace the drained coolant

13. Start the vehicle and leak check the propane fuel system at each serviced fitting.

FUEL TRIM VALVE (FTV) SOLENOID

REPLACEMENT

(FIGURE 3)

Removal Procedure

1. Disconnect the FTV electrical connection.

2. Remove the fuel supply hose from the FTV

3. Remove the two (2) retaining bolts and retain

4. Remove the FTV retaining Clip and retain

5. Remove the FTV

FIGURE 3 MIXER AND THROTTLE BODY ASSEMBLY

1E1-6 Fuel System

Installation Procedure

Important

• Apply a small amount of O-ring lubricant to the

PTV o-ring before installation

• Be sure to reinstall FTV retaining clip

1. Install FTV to Mixer adapter

2. Install the retaining clip and two bolts

3. Tighten retaining bolts

Tighten

9 N•m (80 lb-in)

4. Connect Fuel supply hose

5. Connect electrical connection

6. Start the vehicle.

TEMPERATURE MANIFOLD ABSOLUTE

PRESSURE (TMAP)

(FIGURE 3)

Removal Procedure

1. Disconnect the TMAP electrical connector

2. Remove the two retaining bolts

3. Remove the TMAP

Installation Procedure

• Apply a small amount of O-ring lubricant to the

PTV o-ring before installation

1. Install in reverse order

2. Tighten retaining bolts

Tighten

7 N•m (62 lb-in)

3. Start the vehicle

ELECTRONIC THROTTLE CONTROL

DEVICE REPLACEMENT

(FIGURE 3)

Removal Procedure

1. Disconnect the negative battery cable.

2. Remove the air intake duct.

1.6 liter Emission Certified GM Engine

3. Disconnect the electronic throttle control device connector

4. Disconnect the FTV supply line

5. Disconnect the PTV vacuum line

6. Disconnect the balance line to the LPR

7. Release mixer fuel inlet hose clamp and remove hose from mixer inlet

8. Remove the four (4) manifold retaining bolts from the throttle body adapter to the manifold and retain bolts

9. Remove plate, and o-ring gasket, discard o-ring

10. Remove the four (4) adapter to mixer adapter bolts and retain

11. Remove electronic throttle control device

12. Remove o-ring gasket and discard

FIGURE 4 ELECTRONIC THROTTLE CONTROL

ASSEMBLY

Installation Procedure

Important

• Lightly Lubricate the both the o-rings of the throttle control device to adapter

• Cover Throttle body adapter opening to prevent debris from entering engine until reassembly

1. Install taper o-ring to the top of the electronic throttle control device

2. Insert into the bottom of the mixer adapter

1.6 liter Emission Certified GM Engine

3. Install Throttle control device to adapter o-ring

4. Install the adapter to the throttle control device using the four (4) retaining screw

Tighten

9 N•m (80 lb-in)

5. Install the manifold to adapter gasket and plate to the adapter

6. Install the four (4) manifold to adapter bolts and secure

Tighten

12 N•m (106 lb-in)

7. Install balance line to the LPR

8. Install the PTV vacuum line

9. Install the fuel supply line to the FTV

10. Install fuel supply line to the mixer and reset clamp

11. Connect the FTV electrical connector

12. Connect the air inlet duct

13. Start engine

Fuel System 1E1-7

Tighten

9 N•m (80 lb-in)

3. Install Throttle body Refer to Electronic Throttle

Control Device Replacement

COOLANT HOSE REPLACEMENT

Removal Procedure

1. Drain coolant

2. Using a hose clamp pliers disconnect both hose clamps on each hose

3. Remove the coolant inlet hose form each fitting

4. Remove the coolant outlet hose

Installation Procedure

Important

• Coolant hose are specifically designed, DO NOT use hose material or length other than the OEM specified parts

• DO NOT mix the inlet or outlet hoses when reinstalling

MIXER REPLACEMENT

FIGURE 4

Removal Procedure

1. Disconnect the negative battery cable.

2. Remove the air intake duct.

3. Remove the Throttle control device Refer to Electronic

Throttle Control Device Replacement

4. Remove the four (4) bolts to the throttle control device to mixer adapter bolts

5. Remove and discard the mixer to adapter o-ring

Installation Procedure

Important

• Lightly Lubricate the o-ring of the Mixer to adapter sealing o-ring before installing

• Cover Throttle body adapter opening to prevent debris from entering engine until reassembly

1. Install hose clamps and set back on each hose

2. Reinstall the coolant inlet hose to each fitting

3. Reinstall the coolant outlet hose to each fitting

4. Reset clamps

5. Refill with coolant

6. Start engine and check for coolant leaks

VAPOR HOSE REPLACEMENT

1. Using a hose clamp pliers disconnect both hose clamps

2. Remove the vapor hose form each fitting

Installation Procedure

Important

• Vapor supply hose is specifically designed, DO

NOT use hose material or length other than the

OEM specified parts

1. Install Mixer to adapter o-ring onto the mixer

2. Install the mixer to the throttle control device to mixer adapter and secure with the 4 retaining screw

3. Install hose clamps and set back on each hose

4. Reinstall the vapor hose to each fitting

5. Reset clamps

1E1-8 Fuel System

6. Start engine and check for leaks

BALANCE LINE HOSE REPLACEMENT

1. Remove the clamp to the fitting at the mixer

2. Remove small hose to check valve

3. Remove and retain check valve

4. Remove the one (1) hose routing retaining bolt and retain

5. Remove clamp at the LPR connection

Installation Procedure

Important

• Balance line hoses are specifically designed, DO

NOT use hose material or length other than the

OEM specified parts

• DO NOT mix the hoses when reinstalling

• Install check valve in correct direction (Arrow on check valve pointing toward mixer)

1.6 liter Emission Certified GM Engine

6. Reinstall hose at the mixer and set clamp

7. Start engine and check for leaks

FTV HOSE REPLACEMENT

1. Using a small screw driver push locking clips back on

FTV connection at FTV and LPR

2. Remove the hose and discard

Installation Procedure

Important

• FTV hoses are specifically designed, DO NOT use hose material or length other than the OEM specified parts

3. Reinstall hose at the PTV and LPR and push locks in place

4. Start engine and check for leaks

7. Install hose clamps and set back on each hose

8. Reinstall the LPR hose end to the LPR fitting and set clamp

9. Install Check valve and set clamp (Directional part arrow pointing to mixer)

10. Reinstall the small hose section and set clamps

11. Start engine and check for leaks

ENGINE CONTROL MODULE

REPLACEMENT

1. Disconnect Negative battery cable

2. Remove controller from mounting bracket

3. Push connector lock back to unlock connector

4. Unplug controller and remove

Installation Procedure

Important

• Controller is calibrated for each engine verify you have the correct controller

PTV HOSE REPLACEMENT

1. Using a hose clamp pliers disconnect the clamps on the hose fitting at the mixer

2. Using a small screw driver push locking clip back on

PTV connection

3. Remove the hose and discard

Installation Procedure

Important

• PTV hoses are specifically designed, DO NOT use hose material or length other than the OEM specified parts

5. Plug connector into controller

6. Push lock into place

7. Mount controller into mounting bracket

8. Reconnect the battery cable

9. Install Diagnostic service tool

10. Start engine

11. Check for any DTC codes and clear

12. Verify engine is in closed loop and no MIL lights are present

4. Install hose clamps and set back on the mixer hose end

5. Reinstall hose at the PTV and push lock in place

1.6 liter Emission Certified GM Engine

HEATED EXHAUST GAS OXYGEN SENSOR

REPLACEMENT

1. Disconnect Negative battery cable

2. Disconnect the O-2 sensor electrical connector

3. Using a O-2 Sensor socket remove the O-2 Sensor and discard

Installation Procedure

Important

• Before install the O-2 sensor lubricate threads with anti-seize compound GM P/N 5613695 or equivalent. Avoid getting compound on the sensor tip

4. Install O-2 sensor

Tighten

41 N•m (30 lb-ft)

5. Start engine

6. Check for any DTC codes and clear

7. Verify engine is in closed loop and no MIL lights are present

THREE WAY CATALYTIC CONVERTER

MUFFLER REPLACEMENT

1. Remove the TWC muffler using the OEM end product processes

Installation Procedure

Important

• The Three Way Catalytic converter is specifically designed to meet the emission control of the certified engine. Use only the OEM specified parts

2. Install the TWC muffler using the OEM end product processes

3. Start engine

4. Check for any DTC codes and clear

5. Verify engine is in closed loop and no MIL lights are present

Fuel System 1E1-9

Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement