Workshop Manual Pajero Pinin

Workshop Manual Pajero Pinin
ANTI-SKID
BRAKING SYSTEM
(ABS) <4WD>
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35B-1
ANTI-SKID
BRAKING SYSTEM
(ABS) <4WD>
CONTENTS
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GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 3
Brake Fluid Level Sensor Check
. . . . . . . . . . . . . . . . . . . . . . . . . . Refer to GROUP 35A
SERVICE SPECIFICATIONS . . . . . . . . . . . . . . . . . 3
Bleeding . . . . . . . . . . . . . . . . . Refer to GROUP 35A
LUBRICANTS . . . . . . . . . . Refer to GROUP 35A
Disc Brake Pad Check and Replacement
. . . . . . . . . . . . . . . . . . . . . . . . . . Refer to GROUP 35A
SEALANTS . . . . . . . . . . . . Refer to GROUP 35A
Disc Brake Rotor Check . . . Refer to GROUP 35A
SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Brake Disc Thickness Check
. . . . . . . . . . . . . . . . . . . . . . . . . . Refer to GROUP 35A
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . 5
Brake Disc Run-out Check and Correction
. . . . . . . . . . . . . . . . . . . . . . . . . . Refer to GROUP 35A
ON-VEHICLE SERVICE . . . . . . . . . . . . . . . . . . . . 22
Wheel Speed Sensor Output Voltage Check
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Brake Pedal Check and Adjustment
. . . . . . . . . . . . . . . . . . . . . . . . . . Refer to GROUP 35A
ABS Warning Lamp Relay Continuity Check
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Brake Booster Operating Test
. . . . . . . . . . . . . . . . . . . . . . . . . . Refer to GROUP 35A
Hydraulic Unit Check . . . . . . . . . . . . . . . . . . . . . . . . 24
Check Valve Operation Check
. . . . . . . . . . . . . . . . . . . . . . . . . . Refer to GROUP 35A
Load Sensing Spring Length Check and
Adjustment . . . . . . . . . . . . . . . Refer to GROUP 35A
Load Sensing Proportioning Valve Function
Test . . . . . . . . . . . . . . . . . . . . . Refer to GROUP 35A
Remedy for a Flat Battery . . . . . . . . . . . . . . . . . . . 25
BRAKE PEDAL . . . . . . . . Refer to GROUP 35A
MASTER CYLINDER AND BRAKE
BOOSTER . . . . . . . . . . . . Refer to GROUP 35A
CONTINUED ON NEXT PAGE
35B-2
FRONT DISC BRAKE . . Refer to GROUP 35A
HYDRAULIC UNIT AND ABS-ECU . . . . . . . . . 26
REAR DISC BRAKE . . . . Refer to GROUP 35A
WHEEL SPEED SENSOR . . . . . . . . . . . . . . . . . . 29
LOAD SENSING PROPORTIONING
VALVE . . . . . . . . . . . . . . . . . Refer to GROUP 35A
G SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
ABS <4WD> – General Information/Service Specifications
35B-3
GENERAL INFORMATION
The ABS consists of components such as the wheel
speed sensors, stop lamp switch, hydraulic unit
assembly (integrated with the ABS-ECU) and the
ABS warning lamp. If a problem occurs in the
system, the malfunctioning components can be
identified and the trouble symptoms will be
memorized by the diagnosis function.
In addition, reading of diagnosis codes and service
data and actuator testing are possible by using the
MUT-II.
WHEEL SPEED SENSOR
Type
Magnet coil type
ABS rotor teeth
43
CONSTRUCTION DIAGRAM
ABS warning
lamp
Hydraulic unit
assembly
(integrated with
the ABS-ECU)
Diagnosis
connector
G-sensor
Wheel speed sensor
Stop lamp switch
Wheel speed sensor
SERVICE SPECIFICATIONS
Items
Standard value
Wheel speed sensor internal resistance kΩ
1.30 – 1.58
Wheel speed sensor insulation resistance kΩ
100 or more
G sensor output voltage V
When labeled surface is faced to vertical direction
2.4 – 2.6
When labeled surface is faced straight down
3.3 – 3.7
35B-4
ABS <4WD> – Special Tools
SPECIAL TOOLS
Tool
Number
Name
Use
MB991502
MUT-II sub
assembly
For checking of ABS
(Diagnosis code display when using the
MUT-II)
MB991529
Diagnosis code
check harness
For checking of ABS
(Diagnosis code display when using the ABS
warning lamp)
MB991547
ABS check
harness
For measuring of ABS-ECU terminal voltage
MB991348
Test harness set
For checking of G sensor
ABS <4WD> – Troubleshooting
35B-5
TROUBLESHOOTING
STANDARD FLOW OF DIAGNOSTIC TROUBLESHOOTING
Refer to GROUP 00 – How to Use Troubleshooting/Inspection Service Points.
NOTES WITH REGARD TO DIAGNOSIS
1. The phenomena listed in the following table are not abnormal.
Phenomenon
Explanation of phenomenon
System check sound
When starting the engine, a thudding sound can sometimes be heard coming from inside
the engine compartment, but this is because the system operation check is being performed,
and is not an abnormality.
ABS operation sound
1.
2.
3.
System check sound
When depressing the brake pedal during driving, a shock is sometime felt.
Sound of the motor inside the ABS hydraulic unit operation. (whine)
Sound is the generated along with vibration of the brake pedal. (scraping)
When ABS operates, sound is generated from the vehicle chassis due to repeated
brake application and release.
(Thump: suspension; squeak: tyres)
2. For road surfaces such as snow-covered roads and gravel roads, the braking distance for vehicles
with ABS can sometimes be longer than that for other vehicles. Accordingly, advise the customer
to drive safely on such roads by lowering the vehicle speed and not being too overconfident.
3. Diagnosis detection condition can vary depending on the diagnosis code.
Make sure that checking requirements listed in the “Comment” are satisfied when checking the trouble
symptom again.
Caution
Use the special tool (MB991547) when checking the terminal voltage and resistance of ABS-ECU.
35B-6
ABS <4WD> – Troubleshooting
ABS WARNING LAMP INSPECTION
Check that the ABS warning lamp illuminates as follows.
1. When the ignition key is turned to “ON”, the ABS warning
lamp illuminates for approximately 3 seconds and then
switches off.
2. When the ignition key is turned to “START”, the ABS
warning lamp remains illuminated.
3. When the ignition key is turned from “START” back to
“ON”, the ABS warning lamp illuminates for approximately
3 seconds and then switches off.
ABS warning lamp
Approx. 3 s
ABS
warn- Illuminated
Not illumiing
lamp nated
START
Ignition
ON
switch
ACC,
LOCK
Approx. 3 s
NOTE
The ABS warning lamp may remain on until the vehicle
reaches a speed of several km/h. This is limited to cases
where diagnosis code Nos.21 to 24, 53 or 55 have been
recorded because of a previous problem occurring. In
this case, the ABS-ECU keeps the warning lamp
illuminated until the problem corresponding to that
diagnosis code can be detected.
4. If the illumination is other than the above, check the
diagnosis codes.
DIAGNOSIS FUNCTION
READING DIAGNOSIS CODES
Read a diagnosis code by the MUT-II or ABS warning lamp.
(Refer to GROUP 00 – How to Use Troubleshooting/Inspection
Service Points.)
NOTE
Connect the MUT-II to the diagnosis connector (16-pin).
ERASING DIAGNOSIS CODES
When using the MUT-II
Connect the MUT-II to the diagnosis connector (16-pin) and
erase the diagnosis code.
Caution
Turn the ignition key to the LOCK (OFF) position before
connecting or disconnecting the MUT-II.
35B-7
ABS <4WD> – Troubleshooting
When not using the MUT-II
1. Stop the engine.
2. Use the special tool to earth terminal (1) (diagnosis control
terminal) of the diagnosis connector.
3. Turn on the stop lamp switch. (Depress the brake pedal.)
4. After carrying out steps 1. to 3., turn the ignition switch
to ON. Within 3 seconds after turning the ignition switch
to ON, turn off the stop lamp switch (release the brake
pedal). Then, turn the stop lamp switch on and off a total
of 10 times.
MB991529
NOTE
If the ABS-ECU function has been stopped because of
fail-safe operation, it will not be possible to erase the
diagnosis codes.
ON
Ignition switch
LOCK (OFF)
Stop lamp switch
ON
OFF
1 second
ABS warning lamp
ON
OFF
ABS-ECU memory
Within 3
seconds
Within
1
second
1st
Within
1
second
Within Within
1
1
second second
Within Within Within Within
1
1
1
1
second second second second
Within Within
1
1
second second
2nd 3rd 4th 5th 6th 7th 8th 9th 10th
Erasing of
ABS-ECU
diagnosis
codes
complete.
35B-8
ABS <4WD> – Troubleshooting
INSPECTION CHART FOR DIAGNOSIS CODES
Diagnosis code No.
Inspection item
Reference page
11
Front right wheel speed sensor (Open circuit or short circuit)
35B-9
12
Front left wheel speed sensor (Open circuit or short circuit)
35B-9
13
Rear right wheel speed sensor (Open circuit or short circuit)
35B-9
14
Rear left wheel speed sensor (Open circuit or short circuit)
35B-9
15
Wheel speed sensor (Abnormal output signal)
35B-10
16*
ABS-ECU power supply system (Abnormal voltage drop or rise)
35B-11
21
Front right wheel speed sensor
35B-9
22
Front left wheel speed sensor
35B-9
23
Rear right wheel speed sensor
35B-9
24
Rear left wheel speed sensor
35B-9
32
G sensor system
35B-12
33
Stop lamp switch system
35B-13
41
Front right solenoid valve
42
Front left solenoid valve
43
Rear right solenoid valve
44
Rear left solenoid valve
51
Valve relay problem (stays on)
35B-26, 27
(Replace the
hydraulic unit and
ABS-ECU.)
52
Valve relay problem (stays off) or ABS-ECU power supply system
problem
35B-13
53
Motor relay problem (stays off) or ABS-ECU power supply system
problem
54
Motor relay problem (stays on)
35B-26, 27
(Replace the
hydraulic unit and
ABS-ECU.)
55
Motor system (seized pump motor) or ABS-ECU power supply system
problem
35B-13
63
ABS-ECU
35B-26, 27
(Replace the
hydraulic unit and
ABS-ECU.)
The diagnosis codes are output
when there is no response to the
drive signals for respective solenoid
ECU power
valves or the ABS
ABS-ECU
supply system is defective.
NOTE
*: Turning the ignition switch to ACC will erase the diagnosis code No.16.
35B-13
35B-9
ABS <4WD> – Troubleshooting
INSPECTION PROCEDURE FOR DIAGNOSIS CODES
Code Nos.11, 12, 13 and 14 Wheel speed sensor
(open circuit or short circuit)
Probable cause
Code Nos.21, 22, 23 and 24 Wheel speed sensor
Code Nos. 11, 12, 13 and 14 are output if the ABS-ECU detects an open circuit
or short-circuit in the (+) wire or (–) wire in any one of the four wheel speed sensors.
D Malfunction of wheel speed sensor
D Malfunction of wiring harness or connector
D Malfunction of hydraulic unit and ABS-ECU
Code Nos. 21, 22, 23 and 24 are output in the following cases.
D When there is no input from any one of the four wheel speed sensors when
travelling at several km/h or more, even though open circuit can not be verified.
D When a chipped or blocked-up ABS rotor is detected and if the anti-lock system
operates continuously because a malfunctioning sensor or a warped ABS rotor
is causing sensor output to drop.
D
D
D
D
D
D
NG
Wheel speed sensor installation check
OK
NG
Measure at the ABS-ECU connector A-58.
D Disconnect the connector, and measure at the harness side
connector.
D Resistances between 17 and 18, 15 and 14, 2 and 1, 4 and
5
OK: 1.30 – 1.58 kΩ
OK
Wheel bearing check
(Refer to GROUP 26 and
GROUP 27 – On-vehicle
Service.)
Check the following connector: A-58
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
NG
Repair
Replace
Check the trouble symptom.
NG
Repair
NG
NG
ABS rotor check
(Refer to P.35B-30.)
OK
NG
Check the following connectors:
A-58, C-25<L.H. drive vehicles>, C-24<R.H. drive vehicles>, A-24,
A-85, D-24, D-28
NG
Wheel speed sensor
check
(Refer to P.35B-30.)
OK
Wheel speed sensor check (Refer to P.35B-30.)
Replace
Wheel speed sensor output voltage check (Refer to P.35B-22.)
NG
Repair
OK
OK
OK
Malfunction of wheel speed sensor
Malfunction of wiring harness or connector
Malfunction of ABS rotor
Too much gap between the sensor and the ABS rotor
Malfunction of hydraulic unit and ABS-ECU
Malfunction of wheel bearing
Replace
Check the harness wire, and repair if necessary.
D Between each wheel speed sensor and ABS-ECU
35B-10
ABS <4WD> – Troubleshooting
Code No.15 Wheel speed sensor (Abnormal output signal)
Probable cause
This code is output if the output signal of any wheel speed sensor is abnormal
(other than an open circuit or short circuit).
D
D
D
D
D
D
D
NO
Are four tyres equal in size?
Unequal tyre size
Improper installation of wheel speed sensor
Malfunction of wheel speed sensor
Malfunction of wiring harness or connector
Malfunction of ABS rotor
Malfunction of wheel bearing
Malfunction of hydraulic unit and ABS-ECU
Equalize sizes on all tyres.
YES
Check the trouble symptom.
NG
Check the wheel speed sensor installation condition.
NG
Repair
OK
Check the wheel speed sensor output voltage. (Refer to P.35B-22.)
NG
Check the wheel speed sensor. (Refer to P.35B-30.)
OK
OK
Replace
Check the following connector: A-58
OK
Check the trouble symptom.
NG
NG
Repair
Check the ABS rotor. (Refer to P.35B-30.)
OK
NG
Replace
NG
Replace the hydraulic unit and ABS-ECU.
Check the wheel bearing. (Refer to GROUP 26 and GROUP
27 – On-vehicle Service.)
OK
Check the trouble symptom.
NG
Replace
NG
Check the harness wire, and repair if necessary.
D Between each wheel speed sensor and ABS-ECU
35B-11
ABS <4WD> – Troubleshooting
Code No.16 ABS-ECU power supply system (abnormal
voltage drop or rise)
Probable cause
This code is output if the ABS-ECU power supply voltage drops below or rises
above the rated values.
Furthermore, turning the ignition switch to ACC will erase this code.
D Malfunction of battery
D Malfunction of wiring harness or connector
D Malfunction of hydraulic unit and ABS-ECU
Caution
If battery voltage drops or rises during inspection, this code will be output as well. If the voltage
returns to standard value, this code is no longer output.
Before carrying out the following inspection, check the battery level, and refill it if necessary.
NG
Measure at the ABS-ECU connector A-58.
D Disconnect the connector, and measure at the harness side
connector.
D Start the engine. Voltage between 10 and body earth
OK: System voltage
Check the following connectors: A-58, C-40 <R.H. drive
vehicles>, C-02 <R.H. drive vehicles>, C-78 <L.H. drive vehicles>,
C-76 <R.H. drive vehicles>, C-74
OK
NG
OK
Check the trouble symptom.
Check the following connector: A-58
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
NG
Repair
NG
Repair
Check the harness wire, and repair if necessary.
D Between ignition switch and ABS-ECU
35B-12
ABS <4WD> – Troubleshooting
Code No.32 G sensor system
Probable cause
This code is output in the following cases.
D G sensor output voltage is less than 0.5 V or more than 4.5 V. (An open or
short circuit is present in the G sensor circuit.)
D G sensor output voltage does not change. (G sensor output voltage is abnormal.)
D Malfunction of G sensor
D Malfunction of wiring harness or connector
D Malfunction of hydraulic unit and ABS-ECU
NG
G sensor check (Refer to P.35B-31.)
Replace
OK
Measure at the G sensor connector D-29.
D Disconnect the connector, and measure at the harness side
connector.
D Ignition switch: ON
D Voltage between 1 and body earth
OK: System voltage
NG
Check the following connector: D-29
OK
Check the trouble symptom.
NG
Repair
NG
OK
Check the harness wire, and repair if necessary.
D Between ignition switch and G sensor
Measure at the ABS-ECU connector A-58.
D Disconnect the connector, and measure at the harness side
connector.
D Ignition switch: ON
D Voltage between 7 and 20
OK: 2.4 – 2.6 V (When labeled surface is faced to vertical
direction)
Check the following connectors: A-58, C-25 <L.H. drive
vehicles>, D-29
OK
Check the trouble symptom.
NG
Repair
NG
OK
Check the following connector: A-58
OK
Check the trouble symptom.
NG
NG
Repair
NG
Replace the hydraulic unit and ABS-ECU.
Check the harness wire, and repair if necessary.
D Between G sensor and ABS-ECU
35B-13
ABS <4WD> – Troubleshooting
Code No.33 Stop lamp switch system
Probable cause
This code is output in the following cases.
D If the stop lamp switch is continuously on for 15 minutes or more even though
the ABS system is not operating.
D If there is an open circuit in the stop lamp switch input circuit harness.
D Malfunction of stop lamp switch
D Malfunction of wiring harness or connector
D Malfunction of hydraulic unit and ABS-ECU
NO
Does the stop lamp turn on and off normally?
Check the stop lamp switch installation condition.
(Refer to GROUP 35A – On-vehicle Service.)
YES
OK
Measure at the ABS-ECU connector A-58.
D Disconnect the connector, and measure at the harness side
connector.
D Stop lamp switch: ON
D Voltage between 3 and body earth
OK: System voltage
OK
Repair
Check the stop lamp switch. (Refer to GROUP 35A – Brake Pedal.)
OK
NG
NG
Check the following
connector: A-58
OK
NG
Replace
Check the following
connectors:
A-58, C-28 <L.H. drive
vehicles>, C-41 <R.H.
drive vehicles>
NG
Repair
OK
Check the trouble symptom.
Check the following connectors: C-28 <L.H. drive vehicles>,
C-41 <R.H. drive vehicles>, C-02, C-04, C-29
Check the trouble symptom.
NG
Repair
Replace the hydraulic
unit and ABS-ECU.
Repair
NG
Check the trouble symptom.
NG
NG
OK
Check the harness wire, and repair if necessary.
D Between battery and stop lamp switch
D Between stop lamp switch and ABS-ECU
NG
Check the harness wire,
and repair if necessary.
D Between stop lamp
switch and ABS-ECU
Probable cause
Code Nos.41, 42, 43 and 44 Solenoid valve
Code No.52 Valve relay problem (stays off)
Code No.53 Motor relay problem (stays off)
Code No.55 Motor system (seized pump motor)
These codes are output if there is an open circuit or short-circuit in the ABS-ECU
power supply circuit (power supply circuit for solenoid valve and motor), or the internal
circuit in the hydraulic unit and ABS-ECU is defective.
D Malfunction of wiring harness or connector
D Malfunction of hydraulic unit and ABS-ECU
NG
Measure at the ABS-ECU connector A-58.
D Disconnect the connector, and measure at the harness side
connector.
D Voltage between 22 and body earth, and between 24 and
body earth
OK: System voltage
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
OK
Check the trouble symptom.
NG
Repair
NG
Check the following connector: A-58
OK
Check the following connectors: A-58, C-24 <R.H. drive
vehicles>
NG
Repair
Check the harness wire, and repair if necessary.
D Between fusible link No.1 and ABS-ECU
35B-14
ABS <4WD> – Troubleshooting
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptoms
Inspection procedure
No.
Reference page
Communication between the MUT-II and the whole system is not
possible.
1
35B-14
Communication between the MUT-II and the ABS-ECU is not possible.
2
35B-15
When the ignition key is turned to “ON” (engine stopped), the ABS warning
lamp does not illuminate.
3
35B-16
Even after the engine is started, the ABS warning lamp remains
illuminated.
4
35B-17
Faulty ABS operation
5
35B-18
Caution
1. If steering movements are made when driving at high speed, or when driving on road surfaces
with low frictional resistance, or when passing over bumps, the ABS may operate even though
sudden braking is not being applied. Because of this, when getting information from the customer,
check if the problem occurred while driving under such conditions as these.
2. During ABS operation, the brake pedal may vibrate or may not be able to be depressed. Such
phenomena are due to intermittent changes in hydraulic pressure inside the brake line to prevent
the wheels from locking and is not an abnormality.
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
Inspection Procedure 1
Communication between the MUT-II and the whole system
is not possible.
Probable cause
The cause may be a malfunction of the power supply circuit or the earth circuit
of the diagnosis connector.
D Malfunction of diagnosis connector
D Malfunction of wiring harness or connector
NG
Measure at the diagnosis connector C-35.
D Voltage between 16 and body earth
OK: System voltage
Check the following connectors: C-35, C-76, C-77
OK
Check the trouble symptom.
OK
NG
Repair
NG
Check the harness wire, and repair if necessary.
D Between fusible link No.2 and diagnosis connector
NG
Measure at the diagnosis connector C-35.
D Continuity between 4 and body earth, and between 5 and
body earth
OK: Continuity
OK
Check the trouble symptom.
NG
Replace the MUT-II.
Check the following connector: C-35
OK
Check the trouble symptom.
NG
NG
Repair
Check the harness wire, and repair if necessary.
D Between diagnosis connector and earth
35B-15
ABS <4WD> – Troubleshooting
Inspection Procedure 2
Communication between MUT-II and the ABS-ECU is not
possible.
Probable cause
The cause may be an open circuit in the ABS-ECU power supply circuit or an open
circuit in the diagnosis output circuit.
D Blown fuse
D Malfunction of wiring harness or connector
D Malfunction of hydraulic unit and ABS-ECU
NG
Measure at the diagnosis connector C-35 and the ABS-ECU connector A-58.
D Disconnect the connectors, and measure at the harness side
connectors.
D Continuity between the following terminals
ABS-ECU side – Diagnosis connector side
19 – 1
9 – 7
OK: Continuity
Check the following connectors: A-58, C-28 <L.H. drive
vehicles>, C-40 <R.H. drive vehicles>, C-70, C-35
OK
Check the trouble symptom.
NG
Repair
NG
Check the harness wire, and repair if necessary.
D Between ABS-ECU and diagnosis connector
OK
NG
Measure at the ABS-ECU connector A-58.
D Disconnect the connector, and measure at the harness side
connector.
D Ignition switch: ON
D Voltage between 10 and body earth
OK: System voltage
Check the following connectors: A-58, C-40 <R.H. drive
vehicles>, C-02 <R.H. drive vehicles>, C-78 <L.H. drive vehicles>,
C-76 <R.H. drive vehicles>, C-74
OK
Check the trouble symptom.
OK
NG
Repair
NG
Check the harness wire, and repair if necessary.
D Between ignition switch and ABS-ECU
Measure at the ABS-ECU connector A-58.
D Disconnect the connector, and measure at the harness side
connector.
D Continuity between 21 and body earth, and between 23 and
body earth
OK: Continuity
OK
Check the following connector: A-58
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
NG
Repair
NG
Check the following connector: A-58
OK
Check the trouble symptom.
NG
NG
Repair
Check the harness wire, and repair if necessary.
D Between ABS-ECU and earth
35B-16
ABS <4WD> – Troubleshooting
Inspection Procedure 3
When the ignition key is turned to “ON” (engine stopped),
the ABS warning lamp does not illuminate.
Probable cause
The cause may be an open circuit in the lamp power supply circuit, a blown lamp,
a malfunction of the ABS warning lamp relay or an open circuit between the ABS
warning lamp and the earth.
D
D
D
D
D
Blown fuse
Burn out ABS
Malfunction of
Malfunction of
Malfunction of
warning lamp bulb
ABS warning lamp relay
wiring harness or connector
hydraulic unit and ABS-ECU
NG
Refer to GROUP 00 – Inspection Service Points for Blown Fuse.
Fuse check
Multi-purpose fuse No.6
OK
NG
Measure at the ABS warning lamp relay connector A-57.
D Disconnect the connector, and measure at the harness side
connector.
D Ignition switch: ON
D ABS warning lamp condition when terminal 3 is earthed.
OK: Illuminates
Check whether the ABS warning lamp bulb is burnt out.
Replace the ABS warning
lamp bulb.
OK
Check the following connectors: A-57,
C-27 <L.H. drive vehicles>, C-40 <R.H. drive vehicles>,
C-07, C-06, C-02 <L.H. drive vehicles>, C-76, C-74
ABS warning lamp relay check (Refer to P.35B-23.)
NG
OK
NG
OK
OK
Replace the ABS warning
lamp relay.
Check the trouble symptom.
NG
Repair
NG
Check the harness wire.
D Between ignition switch and combination meter
D Between combination meter and ABS warning lamp relay
OK
NG
Repair
Replace the combination meter.
NG
Measure at the ABS warning lamp relay connector A-57.
D Disconnect the connector, and measure at the harness side
connector.
D Ignition switch: ON
D Continuity between 1 and body earth
OK: Continuity
OK
Replace the hydraulic unit and ABS-ECU.
Check the following connector: A-57
OK
Check the trouble symptom.
NG
Repair
NG
Check the harness wire, and repair if necessary.
D Between ABS warning lamp relay and earth
35B-17
ABS <4WD> – Troubleshooting
Inspection Procedure 4
Even after the engine is started, the ABS warning lamp
remains illuminated.
Probable cause
The cause is probably a short-circuit in the ABS warning lamp illumination circuit.
D
D
D
D
Malfunction
Malfunction
Malfunction
Malfunction
of
of
of
of
combination meter
ABS warning lamp relay
wiring harness (short circuit)
hydraulic unit and ABS-ECU
NOTE
This trouble symptom is limited to cases where communication with the MUT-II is possible (ABS-ECU
power supply is normal) and the diagnosis code is a normal diagnosis code.
YES
Replace the combination meter.
Does the ABS warning lamp stay illuminated when the combination
meter connector C-07 is disconnected and the ignition switch
is turned to ON?
NO
NG
ABS warning lamp relay check (Refer to P.35B-23.)
Replace the ABS warning lamp relay.
OK
YES
Check the harness wire, and repair if necessary.
D Between combination meter and ABS warning lamp relay
Does the ABS warning lamp stay illuminated when the ABS warning
lamp relay connector A-57 is disconnected and the ignition switch
is turned to ON?
NO
NG
Measure at the ABS warning lamp relay connector A-57.
D Disconnect the connector, and measure at the harness side
connector.
D Ignition switch: ON
D Voltage between 5 and body earth
OK: System voltage
Check the following connector: A-57
OK
Check the trouble symptom.
NG
Repair
NG
OK
Check the harness wire, and repair if necessary.
D Between ignition switch and ABS warning lamp relay
NG
Measure at the ABS-ECU connector A-58.
D Ignition switch: ON
D Voltage between 8 and body earth
OK: System voltage
OK
Replace the hydraulic unit and ABS-ECU.
Check the following connectors: A-58, A-57
OK
NG
Check the trouble symptom.
Repair
NG
Check the harness wire, and repair if necessary.
D Between ABS warning lamp relay and ABS-ECU
35B-18
ABS <4WD> – Troubleshooting
Inspection Procedure 5
Faulty ABS operation
Probable cause
This varies depending on the driving conditions and the road surface conditions,
so problem diagnosis is difficult. However, if a normal diagnosis code is displayed,
carry out the following inspection.
D
D
D
D
D
D
D
NG
Wheel speed sensor installation check
Improper installation of wheel speed sensor
Malfunction of wiring harness or connector
Malfunction of wheel speed sensor
Malfunction of ABS rotor
Foreign material adhering to wheel speed sensor
Malfunction of wheel bearing
Malfunction of hydraulic unit and ABS-ECU
Repair
OK
OK
Wheel speed sensor output voltage check (Refer to P.35B-22.)
Hydraulic unit check (Refer to P.35B-24.)
NG
NG
Wheel speed sensor check (Refer to P.35B-30.)
Replace the wheel speed sensor.
OK
ABS rotor check (Refer to P.35B-30.)
NG
Repair
OK
Wheel bearing check (Refer to GROUP 26 and GROUP 27 –
On-vehicle Service.)
NG
Repair
OK
Check the following connectors:
A-58, C-25 <L.H. drive vehicles>, C-24 <R.H. drive vehicles>,
A-24, A-85, D-24, D-28
NG
Repair
OK
Check the trouble symptom.
NG
Measure at the ABS-ECU connector A-58.
D Disconnect the connector, and measure at the harness side
connector.
D Resistances between 17 and 18, 15 and 14, 4 and 5, 2 and
1
OK: 1.30 – 1.58 kΩ
(The sensor harness and connector should be moved while
these inspections are carried out.)
OK
Check the following connector: A-58
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
NG
NG
Check the harness wire.
D Between each wheel speed sensor and ABS-ECU
Repair
35B-19
ABS <4WD> – Troubleshooting
DATA LIST REFERENCE TABLE
The following items can be read by the MUT-II from the ABS-ECU input data.
1. When the system is normal
Item No.
Check item
Checking requirements
Normal value
11
Front-right wheel speed sensor
Perform a test run
12
Front-left wheel speed sensor
13
Rear-right wheel speed sensor
Vehicle speeds
displayed on the
speedometer
MUT II are
and MUT-II
identical.
14
Rear-left wheel speed sensor
16
ABS-ECU power supply
voltage
Ignition switch: ON
9.2 – 17.5 V
32
G sensor
Vehicle is stopped.
2.4 – 2.6 V
Vehicle is running.
0.5 – 4.5 V
Depress the brake pedal.
ON
Release the brake pedal.
OFF
33
Stop lamp switch
2. When the ABS-ECU shut off ABS operation.
When the diagnosis system stops the ABS-ECU, the MUT-II display data will be unreliable.
ACTUATOR TEST REFERENCE TABLE
The MUT-II activates the following actuators for testing.
NOTE
1. If the ABS-ECU runs down, actuator testing cannot be carried out.
2. Actuator testing is only possible when the vehicle is stationary.
ACTUATOR TEST SPECIFICATIONS
Activation pattern
A
Solenoid
B
valve
C
0.05 s
ON
Pump
motor
OFF
Start of
forced
action
1s
End of forced
action
2s
0.01 s
NOTE
A: Hydraulic pressure increase
B: Hydraulic pressure holds
C: Hydraulic pressure decrease
No.
Item
01
Solenoid valve for
front-right wheel
02
Solenoid valve for front-left
wheel
03
Solenoid valve for rear-right
wheel
04
Solenoid valve for rear-left
wheel
Solenoid valves and pump
motors in the hydraulic unit
(simple inspection mode)
35B-20
ABS <4WD> – Troubleshooting
CHECK AT ABS-ECU
TERMINAL VOLTAGE CHECK CHART
1. Disconnect the ABS-ECU connector. (Refer to P. 35B-27.)
2. Use the special tool to measure the voltage between each
terminal and earth (terminal No.23).
3. The terminal layout is shown in the illustration.
Earth terminal
Check connector
MB991547
Body side harness
ABS-ECU
Terminal No.
Check item
Checking requirements
3
Stop lamp switch input
Ignition switch: ON
7
Input
In
ut from G sensor
Ignition switch: ON
Vehicle is horizontal
8
ABS warning lamp
relay transistor output
Ignition switch: ON
Normal condition
Stop lamp switch: ON
System voltage
Stop lamp switch: OFF
1 V or less
2.4 – 2.6 V
When the lamp
switched off
is
When the lamp is illuminated
9
10
19
MUT-II
ABS-ECU power
supply
Diagnosis changeover
input
2 V or less
System voltage
When the MUT-II is connected
Serial communication
with MUT-II
When the MUT-II is not connected
1 V or less
Ignition switch: ON
System voltage
Ignition switch: START
0V
When the MUT-II is connected
0V
When the MUT-II is not connected
Approx. 12 V
20
G sensor earth
Always
0V
22
Solenoid valve power
supply
Always
System voltage
24
Motor power supply
Always
System voltage
35B-21
ABS <4WD> – Troubleshooting
RESISTANCE AND CONTINUITY BETWEEN
HARNESS-SIDE CONNECTOR TERMINALS
1. Turn the ignition key to the LOCK (OFF) position.
2. Disconnect the ABS-ECU connector. (Refer to P. 35B-27.)
3. Use the special tool to check the resistance and continuity
between the terminals indicated in the table below.
4. The terminal layout is shown in the illustration.
Check connector
MB991547
Body side harness
ABS-ECU
ABS–ECU terminal No.
Signal
Normal condition
1–2
Wheel speed sensor (rear left)
1.30 – 1.58 kΩ
4–5
Wheel speed sensor (rear right)
14 – 15
Wheel speed sensor (front left)
17 – 18
Wheel speed sensor (front right)
21 – Body earth
Earth
23 – Body earth
Earth
Continuity
35B-22
ABS <4WD> – On-vehicle Service
ON-VEHICLE SERVICE
WHEEL SPEED SENSOR OUTPUT VOLTAGE
CHECK
Check connector
MB991547
Body side harness
1. Lift up the vehicle and release the parking brake.
2. Disconnect the ABS-ECU connector and then connect
the special tool to the harness side connector. (Refer to
P. 35B-27.)
3. Rotate the wheel to be measured at approximately 1/2–1
rotation per second, and check the output voltage using a
circuit tester or an oscilloscope.
Wheel speed
sensor
Front
left
Front
right
Rear left
Rear
right
Terminal No.
15
17
2
4
14
18
1
5
Output voltage
ABS-ECU
When measuring with a circuit tester:
42 mV or more
When measuring with an oscilloscope:
120 mV p-p or more
4. The followings are suspected if the output voltage is lower
than the value described above. Check the wheel speed
sensor, and replace if necessary.
D Too large clearance between the pole piece of the
wheel speed sensor and ABS rotor
D Faulty wheel speed sensor
When turning by hand
When idling (5 – 6 km/h), 1st gear (M/T)
or D range (A/T)
10.0 ms/DIV 1
V/DIV
Inspecting Waveforms With An Oscilloscope
Use the following method to observe the output voltage
waveform from each wheel speed sensor with an oscilloscope.
D Start the engine, and rotate the rear wheels by engaging
1st gear (vehicles with manual transmission) or D range
(vehicles with automatic transmission). Turn the front
wheels manually so that they rotate at a constant speed.
NOTE
1. The waveform measurements can also be taken while
the vehicle is actually moving.
2. The output voltage will be small when the wheel speed
is low, and similarly it will be large when the wheel speed
is high.
35B-23
ABS <4WD> – On-vehicle Service
Points In Waveform Measurement
Symptom
Probable causes
Remedy
Too small or zero waveform
amplitude
Faulty wheel speed sensor
Replace sensor
Waveform amplitude fluctuates
excessively (this is no problem
roblem if
the minimum amplitude is 100 mV
or more)
Axle hub eccentric or with large runout
Replace hub
Faulty ABS-ECU earth
Repair
Noisy or disturbed waveform
Open circuit in sensor
Replace sensor
Open circuit in harness
Correct harness
Incorrectly mounted wheel speed sensor
Mount correctly
ABS rotor with missing or damaged teeth
Replace ABS rotor
Caution
Because the wheel speed sensor cables move together with the front and rear suspension, they vibrate
greatly when driving over poor road surfaces. As a result, the sensor harnesses should also be shaken
when monitoring of output waveforms of the wheel speed sensors in order to simulate conditions such
as driving over poor road surfaces.
<L.H. drive vehicles>
Hydraulic unit
and ABS-ECU
ABS WARNING LAMP RELAY CONTINUITY
CHECK
Battery voltage
Terminal No.
1
Power is not
supplied
Power is supplied
<R.H. drive vehicles>
Hydraulic unit
and ABS-ECU
2
3
5
35B-24
ABS <4WD> – On-vehicle Service
HYDRAULIC UNIT CHECK
1. Jack up the vehicle and support the vehicle with rigid racks placed at the specified jack-up points
or place the wheels which are checked on the rollers of the braking force tester.
Caution
(1) The roller of the braking force tester and the tyre should be dry during testing.
(2) When testing the front brakes, apply the parking brake, and when testing the rear brakes,
stop the front wheels by chocking them.
2. Turn the ignition key to the LOCK (OFF) position and set the MUT-II.
Caution
Turn the ignition key to the LOCK (OFF) position before connecting or disconnecting the MUT-II.
3. After checking that the shift lever <M/T> or the selector lever <A/T> is in neutral, start the engine.
4. Use the MUT-II to force-drive the actuator.
NOTE
(1) During the actuator test, the ABS warning lamp will illuminate and the anti-skid control will be
cancelled.
(2) When the ABS has been interrupted by the fail-safe function, the MUT-II actuator testing cannot
be used.
5. Turn the wheel by hand and check the change in braking force when the brake pedal is depressed.
When using the braking force tester, depress the brake pedal until the braking force is at the following
values, and check that the braking force decreases when the actuator is force-driven.
Front wheel
785 – 981 N
Rear wheel
588 – 784 N
The result should be as shown in the following diagram.
Pedal operation
Depressed
Released
Increase in pressure
Solenoid valve
position
Steady pressure
Reduction in pressure
Checking the
brake force
MUT-II actuator test
(Item No. 01, 02, 03, 04) start
Lock
Drag force when the pedal is free
2 seconds
1 seconds
Approx. 0.05 seconds
ABS <4WD> – On-vehicle Service
35B-25
6. If the result of inspection is abnormal, correct according to the “Diagnosis Table”.
Diagnosis Table
No.
Operation
Judgement
– Normal
Judgement
– Abnormal
Probable cause
Remedy
01
(1) Depress brake pedal
to lock wheel.
(2) Using the MUT-II,
select the wheel to be
checked and force the
actuator to operate.
(3) Turn the selected
wheel manually to
check the change of
brake force.
Brake force
released for 3
seconds after
locking
locking.
Wheel does not
lock when brake
pedal is depressed
pressed.
Clogged brake
line other than
hydraulic unit
Check and clean
brake line
Clogged hydraulic circuit in
hydraulic unit
Replace hydraulic unit assembly
Incorrect hydraulic unit brake
tube connection
Connect correctly
Hydraulic unit
solenoid valve
not functioning
correctly
Replace hydraulic unit assembly
02
03
04
Brake force is
not released
7. After inspection, disconnect the MUT-II immediately after turning the ignition switch to OFF.
REMEDY FOR A FLAT BATTERY
When booster cables are used to start the engine when the
battery is completely flat and then the vehicle is immediately
driven without waiting for the battery to recharge itself to some
extent, the engine may misfire, and driving might not be
possible.
This happens because ABS consumes a great amount of
current for its self-check function; the remedy is to either allow
the battery to recharge sufficiently, or to disconnect the
ABS-ECU connector, thus disabling the anti-skid brake system.
The ABS warning lamp will illuminate when the ABS-ECU
connector is disconnected.
After the battery has sufficiently recharged, connect the
ABS-ECU connector and restart the engine; then check to
be sure the ABS warning lamp is not illuminated.
Lock lever
Hydraulic unit and
ABS-ECU
DISCONNECTING ABS-ECU CONNECTOR
Move the lock lever of the ABS-ECU connector as shown
in the illustration, and then disconnect the ABS-ECU connector.
35B-26
ABS <4WD> – Hydraulic Unit and ABS-ECU
HYDRAULIC UNIT AND ABS-ECU
REMOVAL AND INSTALLATION
Pre-removal Operation
D Brake Fluid Draining
D Air Cleaner Removal (Refer to GROUP 15.)
Post-installation Operation
D Brake Fluid Supplying and Brake Line Bleeding
(Refer to GROUP 35A – On-vehicle Service.)
D Hydraulic Unit Inspection (Refer to P.35B-24.)
D Air Cleaner Installation (Refer to GROUP 15.)
<L.H. drive vehicles>
3
3
4
15 Nm
2
5
1
ABS <4WD> – Hydraulic Unit and ABS-ECU
35B-27
<R.H. drive vehicles>
3
3
4
15 Nm
2
5
1
Removal steps
1. ABS warning lamp relay
AA"
2. Harness connector
"AA 3. Brake pipe connection
AB"
4. Hydraulic unit and ABS-ECU
5. Hydraulic unit bracket assembly
REMOVAL SERVICE POINTS
Lock lever
Hydraulic unit
and ABS-ECU
AA" HARNESS CONNECTOR DISCONNECTION
Move the lock lever of the ABS-ECU connector as shown
in the illustration, and then disconnect the harness connector.
35B-28
ABS <4WD> – Hydraulic Unit and ABS-ECU
AB" HYDRAULIC UNIT AND ABS-ECU REMOVAL
Caution
1. The hydraulic unit assembly is heavy, and so care
should be taken when removing it.
2. The hydraulic unit assembly is not to be disassembled;
its nuts and bolts should absolutely not be loosened.
3. The hydraulic unit assembly must not be dropped
or otherwise subjected to impact shocks.
4. The hydraulic unit assembly must not be turned upside
down or laid on its side.
5
1
2
INSTALLATION SERVICE POINT
6
3
4
"AA BRAKE PIPE CONNECTION
Connect the pipes to the hydraulic unit assembly as shown
in the illustration.
1. To the proportioning valve (Rear brake, LH)
2. To the proportioning valve (Rear brake, RH)
3. From the master cylinder (Primary)
4. From the master cylinder (Secondary)
5. To the front brake (RH)
6. To the front brake (LH)
35B-29
ABS <4WD> – Wheel Speed Sensor
WHEEL SPEED SENSOR
REMOVAL AND INSTALLATION
Post-installation Operation
Wheel Speed Sensor Output Voltage Check
(Refer to P.35B-22.)
<FRONT>
<REAR>
3
1
4
2
AA"
AA"
1. Front wheel speed sensor
2. Front ABS rotor (Refer to GROUP
26 – Drive Shaft.)
3. Rear wheel speed sensor
4. Rear ABS rotor (Refer to GROUP
27 – Axle Shaft.)
NOTE
The front ABS rotor is integrated with the drive shaft. Do
not disassemble it.
REMOVAL SERVICE POINT
AA" FRONT WHEEL SPEED SENSOR/REAR WHEEL
SPEED SENSOR REMOVAL
Pole piece
Caution
Do not strike the pole piece at the tip of the wheel speed
sensor against the ABS rotor tooth surface or other parts
when removing the wheel speed sensor.
35B-30
ABS <4WD> – Wheel Speed Sensor
INSPECTION
CHECK OF RESISTANCE BETWEEN WHEEL SPEED
SENSOR TERMINALS
Caution
The pole piece can become magnetized because of the
magnet built into the wheel speed sensor, with the result
that metallic foreign material easily adheres to it. Moreover,
the pole piece may not be able to function to correctly
sense the wheel rotation speed if it is damaged.
1. Measure the resistance between the wheel speed sensor
terminals.
Standard value: 1.30 – 1.58 kΩ
If the internal resistance of the wheel speed sensor is
not within the standard value, replace with a new wheel
speed sensor.
2. Check the wheel speed sensor cable for breakage, damage
or disconnection; replace with a new one if a problem
is found.
NOTE
When checking for cable damage, remove the cable clamp
part from the body and then bend and pull the cable near
the clamp to check whether or not temporary disconnection
occurs.
WHEEL SPEED SENSOR INSULATION INSPECTION
1. Remove all connections from the wheel speed sensor,
and then measure the resistance between terminals 1
and 2 and the body of the wheel speed sensor.
Standard value: 100 kΩ or more
2. If the speed sensor insulation resistance is outside the
standard value range, replace with a new speed sensor.
ABS ROTOR CHECK
Check whether ABS rotor teeth are broken or deformed, and,
if so, replace the B.J. assembly or the ABS rotor.
ABS <4WD> – G Sensor
35B-31
G SENSOR
REMOVAL AND INSTALLATION
Caution
Do not drop the G sensor or subject it to any shocks.
Pre-removal and Post-installation Operation
Rear floor console removal and installation
(Refer to Group 52A.)
5 Nm
G sensor
INSPECTION
Label
1. Remove the G sensor.
2. Connect the special tool between the disconnected
connectors, and then place the G sensor horizontally as
shown in the illustration.
3. Turn on the ignition switch, and then measure the voltage
between terminal No.2 and body earth.
Standard value: 2.4 – 2.6 V
MB991348
Label
4. Face the labeled surface straight down with the special
tool still connected. Measure the voltage between terminal
No.2 and body earth with the labeled surface faced straight
down.
Standard value: 3.3 – 3.7 V
5. If not within the standard value, check the power supply
line and earth condition, and then replace the G sensor.
NOTES
35B-1
ANTI-SKID
BRAKING SYSTEM
(ABS) <4WD>
CONTENTS
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
ON-VEHICLE SERVICE . . . . . . . . . . . . . . . . . . . . 14
Outline of Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Wheel Speed Sensor Output Voltage Check
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 2
HYDRAULIC UNIT AND ABS-ECU . . . . . . . . . 15
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . 5
35B-2
ABS <4WD> – General/General Information
GENERAL
OUTLINE OF CHANGES
The hydraulic unit (integrated with the ABS-ECU) has been reshaped. In addition, the troubleshooting
has been changed due to the change on the ABS-ECU connector.
The Electronic Brake-force Distribution (EBD) has been adopted. The EBD makes it possible to maintain
the maximum amount of braking force for the rear wheels even when the vehicle’s load is unevenly
distributed
GENERAL INFORMATION
EBD CONTROL
In ABS, electronic control method is used whereby
the rear wheel brake hydraulic pressure during braking is regulated by rear wheel control solenoid valves
in accordance with the vehicle’s rate of deceleration
and the front and rear wheel slippage which are
calculated from the signals received from the various
wheel sensors. EBD control is a control system
which provides a high level of control for both vehicle
braking force and vehicle stability. The system has
the following features.
Because the system provides the optimum rear
wheel braking force regardless of the vehicle
laden condition and the condition of the road
surface, the system reduces the required pedal
depression force, particularly when the vehicle
is heavily laden or driving on road surfaces with
high frictional coefficients.
Because the duty placed on the front brakes
has been reduced, the increases in pad temperature can be controlled during front brakes applying to improve the wear resistance characteristics of the pad.
Control valves such as the proportioning valve
are no longer required.
HYDRAULIC UNIT
New
Old
Hydraulic unit
Hydraulic unit
35B-3
ABS<4WD> – General Information
ABS-ECU
EBD HYDRAULIC PRESSURE CONTROL
The procedures are the same as that used in PAJERO except for the items shown below.
Item
PAJERO-PININ
PAJERO
EBD control condition
When the difference between the rear
wheel speed and the vehicle speed
exceeds the set value.
When the difference between the
rear wheel speed and the front
wheel speed exceeds the set
value.
<PAJERO-PININ>
Rear wheel
speed sensor
Front wheel
speed sensor
Vehicle speed
EBD control
Set value of
EBD slip ratio
Speed
Set value of
ABS slip ratio
ABS control (Rear wheel)
ABS control (Front wheel)
Time
<PAJERO>
Rear wheel
speed sensor
Front wheel
speed sensor
Vehicle speed
Set value of
EBD slip ratio
Speed
Set value of
ABS slip ratio
EBD control
ABS control (Rear wheel)
ABS control (Front wheel)
Time
35B-4
ABS<4WD> – General Information
FAIL-SAFE FUNCTION
The procedures are the same as that used in PAJERO except for the items shown below.
Item
PAJERO-PININ
PAJERO
Warning lamp during fail-safe operation
ABS warning lamp
Brake warning lamp
Diagnosis
g
code
d No.
N
Item
11
Open circuit or short-circuit in
wheel speed sensor (FR)
12
Open circuit or short-circuit in
wheel speed sensor (FL)
13
Open circuit or short-circuit in
wheel speed sensor (RR)
14
Open circuit or short-circuit in
wheel speed sensor (RL)
15
Problem with any one of the
four wheel speed sensors
16
Action during fail-safe operation
ABS control
EBD control
ABS warning lamp
If faulty wheels include
two rear wheels:
C t l stopped
t
d iin allll
Control
wheels
Other than the above:
Control stopped in faulty
wheels
If faulty wheels include
two rear wheels:
C t l stopped
t
d
Control
Other than the above:
Control carried out
Illuminated
Abnormal drop or rise in
ABS-ECU power supply voltage
Control stopped
Control stopped
Illuminated
21
Wheel speed sensor (FR)
system
Wheel speed sensor (FL)
system
23
Wheel speed sensor (RR)
system
If faulty wheels include
two rear wheels:
C t l stopped
t
d
Control
Other than the above:
Control carried out
Illuminated
22
If faulty wheels include
two rear wheels:
C t l stopped
t
d iin allll
Control
wheels
Other than the above:
Control stopped in faulty
wheels
24
Wheel speed sensor (RL)
system
32
G sensor system
Control stopped
Control carried out
Illuminated
33
Stop lamp switch system
Control stopped
Control carried out
Illuminated
41
Solenoid valve (FR) system
System
y
interrupted
System
y
interrupted
Illuminated
42
Solenoid valve (FL) system
43
Solenoid valve (RR) system
44
Solenoid valve (RL) system
51
Valve relay ON problem
Control stopped
Control carried out
Illuminated
52
Valve relay OFF problem
System interrupted
System interrupted
Illuminated
53
Motor relay OFF problem
Control stopped
Control carried out
Illuminated
54
Motor relay ON problem
System interrupted
Control carried out
Illuminated
55
Motor system
Control stopped
Control carried out
Illuminated
63
ABS-ECU abnormality
System interrupted
System interrupted
Illuminated
NOTE
Control stopped: Control is not carried out until the ignition switch is turned to the “LOCK” (OFF) position.
However, if the problem returns to normal, control is carried out again.
System interrupted: Control is not carried out until the valve relay turns off and the ignition switch is turned
to the “LOCK” (OFF) position.
35B-5
ABS <4WD> – Troubleshooting
TROUBLESHOOTING
INSPECTION CHART FOR DIAGNOSIS CODES
Diagnosis code No.
Inspection item
Reference page
11
Front right wheel speed sensor (Open circuit or short circuit)
35B-6
12
Front left wheel speed sensor (Open circuit or short circuit)
35B-6
13
Rear right wheel speed sensor (Open circuit or short circuit)
35B-6
14
Rear left wheel speed sensor (Open circuit or short circuit)
35B-6
15
Wheel speed sensor (Abnormal output signal)
–
16*
ABS-ECU power supply system (Abnormal voltage drop or rise)
35B-7
21
Front right wheel speed sensor
35B-6
22
Front left wheel speed sensor
35B-6
23
Rear right wheel speed sensor
35B-6
24
Rear left wheel speed sensor
35B-6
32
G sensor system
35B-7
33
Stop lamp switch system
–
41
Front right solenoid valve
42
Front left solenoid valve
43
Rear right solenoid valve
44
Rear left solenoid valve
51
Valve relay problem (stays on)
–
52
Valve relay problem (stays off) or ABS-ECU power supply system
problem
35B-8
53
Motor relay problem (stays off) or ABS-ECU power supply system
problem
54
Motor relay problem (stays on)
–
55
Motor system (seized pump motor) or ABS-ECU power supply system
problem
35B-8
63
ABS-ECU
–
The diagnosis codes are output
when there is no response to the
drive signals for respective solenoid
ABS ECU power
valves or the ABS-ECU
supply system is defective.
NOTE
*: Turning the ignition switch to ACC will erase the diagnosis code No.16.
35B-8
35B-6
ABS <4WD> – Troubleshooting
INSPECTION PROCEDURE FOR DIAGNOSIS CODES
Probable cause
Code Nos.11, 12, 13 and 14 Wheel speed sensor
(open circuit or short circuit)
Code Nos.21, 22, 23 and 24 Wheel speed sensor
Code Nos. 11, 12, 13 and 14 are output if the ABS-ECU detects an open circuit
or short-circuit in the (+) wire or (–) wire in any one of the four wheel speed sensors.
Malfunction of wheel speed sensor
Malfunction of wiring harness or connector
Malfunction of hydraulic unit and ABS-ECU
Code Nos. 21, 22, 23 and 24 are output in the following cases.
When there is no input from any one of the four wheel speed sensors when
travelling at several km/h or more, even though open circuit can not be verified.
When a chipped or blocked-up ABS rotor is detected and if the anti-lock system
operates continuously because a malfunctioning sensor or a warped ABS rotor
is causing sensor output to drop.
NG
Wheel speed sensor installation check
OK
NG
Measure at the ABS-ECU connector A-58.
Disconnect the connector, and measure at the harness side
connector.
Resistances between 26 and 27, 4 and 5, 2 and 1, 24 and
23
OK: 1.30 – 1.58 kΩ
NG
sensor
NG
Check the following connectors:
A-58, C-25<L.H. drive vehicles>, C-24<R.H. drive vehicles>, A-24,
A-85, D-24, D-28
OK
NG
speed
Wheel speed sensor check
Replace
Wheel speed sensor output voltage check (Refer to P.35B-14.)
Wheel
check
Repair
OK
OK
OK
Malfunction of wheel speed sensor
Malfunction of wiring harness or connector
Malfunction of ABS rotor
Too much gap between the sensor and the ABS rotor
Malfunction of hydraulic unit and ABS-ECU
Malfunction of wheel bearing
Replace
Check the trouble symptom.
NG
Repair
NG
OK
NG
ABS rotor check
OK
Wheel bearing check
(Refer to GROUP 26 and
GROUP 27 – On-vehicle
Service.)
Check the following connector: A-58
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
NG
Repair
Replace
Check the harness wire, and repair if necessary.
Between each wheel speed sensor and ABS-ECU
35B-7
ABS <4WD> – Troubleshooting
Code No.16 ABS-ECU power supply system (abnormal
voltage drop or rise)
Probable cause
This code is output if the ABS-ECU power supply voltage drops below or rises
above the rated values.
Furthermore, turning the ignition switch to ACC will erase this code.
Malfunction of battery
Malfunction of wiring harness or connector
Malfunction of hydraulic unit and ABS-ECU
Caution
If battery voltage drops or rises during inspection, this code will be output as well. If the voltage
returns to standard value, this code is no longer output.
Before carrying out the following inspection, check the battery level, and refill it if necessary.
NG
Measure at the ABS-ECU connector A-58.
Disconnect the connector, and measure at the harness side
connector.
Start the engine. Voltage between 32 and body earth
OK: System voltage
Check the following connectors: A-58, C-40 <R.H. drive
vehicles>, C-02 <R.H. drive vehicles>, C-78 <L.H. drive vehicles>,
C-76 <R.H. drive vehicles>, C-74
OK
NG
OK
Check the trouble symptom.
Check the following connector: A-58
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
NG
Repair
NG
Repair
Check the harness wire, and repair if necessary.
Between ignition switch and ABS-ECU
35B-8
ABS <4WD> – Troubleshooting
Code No.32 G sensor system
Probable cause
This code is output in the following cases.
G sensor output voltage is less than 0.5 V or more than 4.5 V. (An open or
short circuit is present in the G sensor circuit.)
G sensor output voltage does not change. (G sensor output voltage is abnormal.)
Malfunction of G sensor
Malfunction of wiring harness or connector
Malfunction of hydraulic unit and ABS-ECU
NG
G sensor check
Replace
OK
Measure at the G sensor connector D-29.
Disconnect the connector, and measure at the harness side
connector.
Ignition switch: ON
Voltage between 1 and body earth
OK: System voltage
NG
Check the following connector: D-29
NG
OK
Check the trouble symptom.
Repair
NG
OK
Check the harness wire, and repair if necessary.
Between ignition switch and G sensor
Measure at the ABS-ECU connector A-58.
Disconnect the connector, and measure at the harness side
connector.
Ignition switch: ON
Voltage between 9 and 6
OK: 2.4 – 2.6 V (When labeled surface is faced to vertical
direction)
NG
Check the following connectors: A-58, C-25 <L.H. drive
vehicles>, D-29
Check the trouble symptom.
Repair
NG
OK
Check the following connector: A-58
OK
Check the harness wire, and repair if necessary.
Between G sensor and ABS-ECU
NG
Check the trouble symptom.
NG
OK
Repair
NG
Replace the hydraulic unit and ABS-ECU.
Probable cause
Code Nos.41, 42, 43 and 44 Solenoid valve
Code No.52 Valve relay problem (stays off)
Code No.53 Motor relay problem (stays off)
Code No.55 Motor system (seized pump motor)
These codes are output if there is an open circuit or short-circuit in the ABS-ECU
power supply circuit (power supply circuit for solenoid valve and motor), or the internal
circuit in the hydraulic unit and ABS-ECU is defective.
Malfunction of wiring harness or connector
Malfunction of hydraulic unit and ABS-ECU
NG
Measure at the ABS-ECU connector A-58.
Disconnect the connector, and measure at the harness side
connector.
Voltage between 34 and body earth, and between 12 and
body earth
OK: System voltage
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
OK
Check the trouble symptom.
NG
Repair
NG
Check the following connector: A-58
OK
Check the following connectors: A-58, C-24 <R.H. drive
vehicles>
NG
Repair
Check the harness wire, and repair if necessary.
Between fusible link No.1 and ABS-ECU
35B-9
ABS <4WD> – Troubleshooting
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptoms
Inspection procedure
No.
Reference page
Communication between the MUT-II and the whole system is not
possible.
1
–
Communication between the MUT-II and the ABS-ECU is not possible.
2
35B-10
When the ignition key is turned to “ON” (engine stopped), the ABS warning
lamp does not illuminate.
3
–
Even after the engine is started, the ABS warning lamp remains
illuminated.
4
35B-11
Faulty ABS operation
5
35B-12
Caution
1. If steering movements are made when driving at high speed, or when driving on road surfaces
with low frictional resistance, or when passing over bumps, the ABS may operate even though
sudden braking is not being applied. Because of this, when getting information from the customer,
check if the problem occurred while driving under such conditions as these.
2. During ABS operation, the brake pedal may vibrate or may not be able to be depressed. Such
phenomena are due to intermittent changes in hydraulic pressure inside the brake line to prevent
the wheels from locking and is not an abnormality.
35B-10
ABS <4WD> – Troubleshooting
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
Inspection Procedure 2
Communication between MUT-II and the ABS-ECU is not
possible.
Probable cause
The cause may be an open circuit in the ABS-ECU power supply circuit or an open
circuit in the diagnosis output circuit.
Blown fuse
Malfunction of wiring harness or connector
Malfunction of hydraulic unit and ABS-ECU
NG
Measure at the diagnosis connector C-35 and the ABS-ECU connector A-58.
Disconnect the connectors, and measure at the harness side
connectors.
Continuity between the following terminals
ABS-ECU side – Diagnosis connector side
19 – 1
21 – 7
OK: Continuity
Check the following connectors: A-58, C-28 <L.H. drive
vehicles>, C-40 <R.H. drive vehicles>, C-70, C-35
OK
Check the trouble symptom.
NG
Repair
NG
Check the harness wire, and repair if necessary.
Between ABS-ECU and diagnosis connector
OK
NG
Measure at the ABS-ECU connector A-58.
Disconnect the connector, and measure at the harness side
connector.
Ignition switch: ON
Voltage between 32 and body earth
OK: System voltage
Check the following connectors: A-58, C-40 <R.H. drive
vehicles>, C-02 <R.H. drive vehicles>, C-78 <L.H. drive vehicles>,
C-76 <R.H. drive vehicles>, C-74
OK
Check the trouble symptom.
OK
NG
Repair
NG
Check the harness wire, and repair if necessary.
Between ignition switch and ABS-ECU
Measure at the ABS-ECU connector A-58.
Disconnect the connector, and measure at the harness side
connector.
Continuity between 33 and body earth, and between 11 and
body earth
OK: Continuity
OK
Check the following connector: A-58
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
NG
Repair
NG
Check the following connector: A-58
OK
Check the trouble symptom.
NG
NG
Repair
Check the harness wire, and repair if necessary.
Between ABS-ECU and earth
35B-11
ABS <4WD> – Troubleshooting
Inspection Procedure 4
Even after the engine is started, the ABS warning lamp
remains illuminated.
Probable cause
The cause is probably a short-circuit in the ABS warning lamp illumination circuit.
Malfunction
Malfunction
Malfunction
Malfunction
of
of
of
of
combination meter
ABS warning lamp relay
wiring harness (short circuit)
hydraulic unit and ABS-ECU
NOTE
This trouble symptom is limited to cases where communication with the MUT-II is possible (ABS-ECU
power supply is normal) and the diagnosis code is a normal diagnosis code.
YES
Replace the combination meter.
Does the ABS warning lamp stay illuminated when the combination
meter connector C-07 is disconnected and the ignition switch
is turned to ON?
NO
NG
ABS warning lamp relay check
Replace the ABS warning lamp relay.
OK
YES
Check the harness wire, and repair if necessary.
Between combination meter and ABS warning lamp relay
Does the ABS warning lamp stay illuminated when the ABS warning
lamp relay connector A-57 is disconnected and the ignition switch
is turned to ON?
NO
NG
Measure at the ABS warning lamp relay connector A-57.
Disconnect the connector, and measure at the harness side
connector.
Ignition switch: ON
Voltage between 5 and body earth
OK: System voltage
Check the following connector: A-57
OK
Check the trouble symptom.
NG
Repair
NG
OK
Check the harness wire, and repair if necessary.
Between ignition switch and ABS warning lamp relay
NG
Measure at the ABS-ECU connector A-58.
Ignition switch: ON
Voltage between 22 and body earth
OK: System voltage
OK
Replace the hydraulic unit and ABS-ECU.
Check the following connectors: A-58, A-57
OK
NG
Check the trouble symptom.
Repair
NG
Check the harness wire, and repair if necessary.
Between ABS warning lamp relay and ABS-ECU
35B-12
ABS <4WD> – Troubleshooting
Inspection Procedure 5
Faulty ABS operation
Probable cause
This varies depending on the driving conditions and the road surface conditions,
so problem diagnosis is difficult. However, if a normal diagnosis code is displayed,
carry out the following inspection.
NG
Wheel speed sensor installation check
Improper installation of wheel speed sensor
Malfunction of wiring harness or connector
Malfunction of wheel speed sensor
Malfunction of ABS rotor
Foreign material adhering to wheel speed sensor
Malfunction of wheel bearing
Malfunction of hydraulic unit and ABS-ECU
Repair
OK
OK
Wheel speed sensor output voltage check (Refer to P.35B-14.)
Hydraulic unit check
NG
NG
Wheel speed sensor check
Replace the wheel speed sensor.
OK
NG
ABS rotor check
Repair
OK
Wheel bearing check (Refer to GROUP 26 and GROUP 27 –
On-vehicle Service.)
NG
Repair
OK
Check the following connectors:
A-58, C-25 <L.H. drive vehicles>, C-24 <R.H. drive vehicles>,
A-24, A-85, D-24, D-28
NG
Repair
OK
Check the trouble symptom.
NG
Measure at the ABS-ECU connector A-58.
Disconnect the connector, and measure at the harness side
connector.
Resistances between 26 and 27, 4 and 5, 24 and 23, 2 and
1
OK: 1.30 – 1.58 kΩ
(The sensor harness and connector should be moved while
these inspections are carried out.)
OK
Check the following connector: A-58
OK
Check the trouble symptom.
NG
Replace the hydraulic unit and ABS-ECU.
NG
NG
Check the harness wire.
Between each wheel speed sensor and ABS-ECU
Repair
35B-13
ABS <4WD> – Troubleshooting
CHECK AT ABS-ECU
TERMINAL VOLTAGE CHECK CHART
1. Measure the voltages between the respective terminal
and earth.
2. The terminal layout is shown in the illustration.
Terminal No.
Check item
Checking requirements
3
Stop lamp switch input
Ignition switch: ON
Normal condition
Stop lamp switch: ON
System voltage
Stop lamp switch: OFF
1 V or less
6
G sensor earth
Always
0V
9
Input
In
ut from G sensor
Ignition switch: ON
Vehicle is horizontal
2.4 – 2.6 V
12
Solenoid valve power
supply
Always
System voltage
19
Diagnosis changeover
input
When the MUT-II is connected
0V
When the MUT-II is not connected
Approx. 12 V
When the MUT-II is connected
Serial communication
with MUT-II
When the MUT-II is not connected
1 V or less
21
22
MUT-II
ABS warning lamp
relay transistor output
Ignition switch: ON
When the lamp
switched off
is
When the lamp is illuminated
32
34
ABS-ECU power
supply
Motor power supply
2 V or less
System voltage
Ignition switch: ON
System voltage
Ignition switch: START
0V
Always
System voltage
RESISTANCE AND CONTINUITY BETWEEN
HARNESS-SIDE CONNECTOR TERMINALS
1. Turn the ignition key to the LOCK (OFF) position.
2. Disconnect the ABS-ECU connector.
3. Check the resistance and continuity between the terminals
indicated in the table below.
4. The terminal layout is shown in the illustration.
35B-14
ABS <4WD> – Troubleshooting/On-vehicle Service
ABS-ECU terminal No.
Signal
Normal condition
1–2
Wheel speed sensor (rear left)
1.30 – 1.58 kΩ
23 – 24
Wheel speed sensor (rear right)
4–5
Wheel speed sensor (front left)
26 – 27
Wheel speed sensor (front right)
11 – Body earth
Earth
33 – Body earth
Earth
Continuity
ON-VEHICLE SERVICE
WHEEL SPEED SENSOR OUTPUT VOLTAGE
CHECK
1. Lift up the vehicle and release the parking brake.
2. Disconnect the ABS-ECU connector.
3. Rotate the wheel to be measured at approximately 1/2–1
rotation per second, and check the output voltage using a
circuit tester or an oscilloscope.
Wheel speed
sensor
Front
left
Front
right
Rear left
Rear
right
Terminal No.
4
26
2
24
5
27
1
23
Output voltage
When measuring with a circuit tester:
42 mV or more
When measuring with an oscilloscope:
120 mV p-p or more
4. The followings are suspected if the output voltage is lower
than the value described above. Check the wheel speed
sensor, and replace if necessary.
Too large clearance between the pole piece of the
wheel speed sensor and ABS rotor
Faulty wheel speed sensor
35B-15
ABS <4WD> – Hydraulic Unit and ABS-ECU
HYDRAULIC UNIT AND ABS-ECU
REMOVAL AND INSTALLATION
Pre-removal Operation
Brake Fluid Draining
Air Cleaner Removal (Refer to GROUP 15.)
Post-installation Operation
Brake Fluid Supplying and Brake Line Bleeding
(Refer to GROUP 35A – On-vehicle Service.)
Hydraulic Unit Inspection
Air Cleaner Installation (Refer to GROUP 15.)
<L.H. drive vehicles>
3
3
4
15 Nm
3
2
5
1
35B-16
ABS <4WD> – Hydraulic Unit and ABS-ECU
<R.H. drive vehicles>
15 Nm
3
3
2
4
1
Removal steps
1. ABS warning lamp relay
A
2. Harness connector
A 3. Brake pipe connection
B
4. Hydraulic unit and ABS-ECU
3
2
5
5. Hydraulic unit bracket assembly
NOTE
The removal service points are the same as before.
INSTALLATION SERVICE POINT
1
4
6
5
A BRAKE PIPE CONNECTION
Connect the pipes to the hydraulic unit assembly as shown
in the illustration.
1. To the front brake (L.H.)
2. To the proportioning valve (Rear brake, R.H.)
3. To the proportioning valve (Rear brake, L.H.)
4. From the master cylinder (Primary)
5. From the master cylinder (Secondary)
6. To the front brake (R.H.)
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