Mitsubishi Pajero Instruction manual

ANTI-SKID BRAKING
SYSTEM (ABS) <4WD>
Click on the applicable bookmark to selected the required model year.
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35B-1
ANTI-SKID
BRAKING SYSTEM
(ABS) <4WD>
CONTENTS
GENERAL INFORMATION 2..................
SERVICE SPECIFICATIONS 4.................
LUBRICANT Refer to GROUP 35A...........
SEALANTS Refer to GROUP 35A............
SPECIAL TOOLS 4..........................
TROUBLESHOOTING 4.......................
ON-VEHICLE SERVICE 27...................
Wheel Speed Sensor Output Voltage
Measurement 27...............................
ABS Valve Relay Continuity Check 28...........
Hydraulic Brake Booster (HBB) - Hydraulic Unit
Check 29......................................
Solenoid Valve Check 30.......................
When the Battery is Flat 31....................
Brake Pedal Check and Adjustment
Refer to GROUP 35A..........................
Hydraulic Brake Booster (HBB) Operation Check
Refer to GROUP 35A..........................
Hydraulic Brake Booster (HBB) Check
Refer to GROUP 35A..........................
Motor Relay Continuity Check
Refer to GROUP 35A..........................
Bleeding Refer to GROUP 35A..................
Brake Fluid Level Sensor Check
Refer to GROUP 35A..........................
Disc Brake Pad Check and Replacement
Refer to GROUP 35A..........................
Brake Disc Thickness Check
Refer to GROUP 35A..........................
Brake Disc Runout Check and Correction
Refer to GROUP 35A..........................
BRAKE PEDAL Refer to GROUP 35A........
HYDRAULIC BRAKE BOOSTER (HBB)
Refer to GROUP 35A........................
HBB BUZZER Refer to GROUP 35A..........
FRONT DISC BRAKE Refer to GROUP 35A..
REAR DISC BRAKE Refer to GROUP 35A....
ABS-ECU 32................................
WHEEL SPEED SENSOR 33.................
G-SENSOR 36..............................
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ABS <4WD> - General Information
35B-2
GENERAL INFORMATION
ABS has been adopted as standard equipment
in all vehicles to maintain directional stability and
steering performance during sudden braking.
The ABS control method used is a 4-sensor,
4-channel method (previous models: 4-sensor,
3-channel method)which allows the brake
pressures for all four wheels to be controlled
independently of each other. The system has the
following features.
DEBD*(Electronic Brake force Distribution
system) control has been added to provide the
ideal braking force for the rear wheels.
DThe hydraulic unit function has been integrated
with the hydraulic brake booster (HBB).
DSelect solenoid valves (two valves for FL and
FR) have been adopted in order to reduce the
pedal kickback and improve the operation
feeling when the ABS is operating.
DIndependent 4-wheel control is carried out wile
the vehicle is turning in order to increase the
braking force.
NOTE
*EBD: Electronic Brake-force Distribution
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.
DBecause 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.
DBecause 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.
DControl valves such as the proportioning valve
are no longer required.
SPECIFICATIONS
Item Specifications
ABS control method 4-sensor, 4-channel
No. of ABS rotor teeth Front 50
Rear 50
ABS speed sensor Type Magnet coil type
Gap between sensor and rotor mm 0.9 (non-adjustable type)
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ABS <4WD> - General Information 35B-3
STRUCTURAL DIAGRAM
Wheel speed sensor
Stop lamp switch
G sensor
Center differential lock switch or
4WD detection switch
Hydraulic brake
booster (HBB)
Valve relay
Diagnosis connector
ABS-ECU
Wheel speed sensor
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ABS <4WD> - Service Specifications/Special Tools/Troubleshooting
35B-4
SERVICE SPECIFICATIONS
Item Standard value
Control solenoid valve resistance WIN 4.75 - 5.25
OUT 2.0 - 2.4
Select solenoid valve resistance W3.5 - 3.9
Wheel speed sensor terminal resistance kW1.0 - 1.5
Wheel speed sensor insulation resistance kW100 or more
SPECIAL TOOLS
Tools No. Name Application
MB991502 MUT-II sub as-
sembly
Checking the ABS
(Diagnosis display using the MUT-II)
MB991529 Diagnosis code
checking harness
Checking the ABS
(Diagnosis display using the ABS warning
lamp)
MB991348 Test harness set Checking the G sensor
TROUBLESHOOTING
STANDARD FLOW OF DIAGNOSTIC TROUBLESHOOTING
Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points.
PRECAUTIONS WHEN CARRYING OUT DIAGNOSIS
(1) The ABS is a system which controls the brake pressure by means of the operation of the ECU.
Accordingly, the following symptoms may occur at times, but these are a sign of normal ABS operation,
and do not indicate a malfunction.
Symptom Explanation of symptom
When the engine starts, a knocking sound can be heard coming from
the engine compartment.
This sound occurs as a result of system
operation checking, and is not a
malfunction.
1. The brake pedal feeling changes and noise is generated.(Rattling)
2. When the ABS is operating, noise is generated by parts of the
vehicle chassis as control turns on and off. (Thump: suspension;
squeak: tyres)
This is the sound of normal system
operation, and is not a malfunction.
Shocks are felt if the brake pedal is depressed when driving at low
speed.
This is due to system operation
checking (starting- of check when the
vehicle speed reaches a certain
number of km/h) and is not a
malfunction.
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ABS <4WD> - Troubleshooting 35B-5
(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 conditions vary according to the diagnosis code. When re-checking trouble
symptoms, the conditions given in the “Explanation” column of the Inspection Chart Classified by
Trouble Symptoms must always be satisfied.
ABS WARNING LAMP INSPECTION
Check that the ABS warning lamp illuminates in the following
way.
Even if the pressure inside the accumulator of the hydraulic
brake booster (HBB) is below the specified value, the ABS
warning lamp will illuminate because ABS operation has been
stopped. In such cases, if the HBB pump is driven by the
accumulated pressure inside the accumulator and causes
the ABS warning lamp to switch off, it does not indicate a
system malfunction.
(1) When the ignition switch is turned to the ON position,
the ABS warning lamp illuminates* for approximately 3
seconds, and then switches off.
(2) When the ignition switch is turned to the START position,
the ABS warning lamp remains illuminated.
(3) When the ignition switch returns from the START to the
ON position, the ABS warning lamp illuminates* for
approximately 3 seconds, and then remains switched off.
(4) If any of the above do not occur, check the diagnosis
codes.
NOTE
*: The ABS warning lamp may remain illuminated after the
ignition switch is turned to the ON position and the vehicle
starts moving until the vehicle speed reaches a speed
of several km/h. This only occurs if a diagnosis code
from No. 21 to No. 24 relating to a wheel speed sensor
malfunction was generate when the ignition switch was
last turned to the ON position and is still stored in the
ABS-ECU. The ABS-ECU will cause the ABS warning
lamp to illuminate until the point where it can ascertain
(during the starting-off check) that the problem associated
with this diagnosis code has returned to normal.
DIAGNOSIS FUNCTION
READING DIAGNOSIS CODES
Use the MUT-II or the ABS warning lamp to read the diagnosis
codes.
(Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points.)
NOTE
Connect the MUT-II to the 16-pin diagnosis connector.
ABS warning lamp
Approx. 3 s Approx. 3 s
ABS warn-
ing lamp On
Off
Ignition
switch
START
ON
ACC,
LOCK
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ABS <4WD> - Troubleshooting
35B-6
ERASING DIAGNOSIS CODES
When using the MUT-II
Connect the MUT-II to the diagnosis connector and erase
the diagnosis codes.
Caution
Turn the ignition switch to the LOCK (OFF) position when
connecting and disconnecting the MUT-II.
NOTE
Connect the MUT-II to the 16-pin diagnosis connector.
When not using the MUT-II
(1) Stop the vehicle.
(2) Turn the stop lamp switch to ON (brake pedal depressed).
(3) In this condition (after carrying out steps 1) to 2)), turn
the ignition switch to the ON position. Then turn off the
stop lamp switch (release the brake pedal) within 3
seconds, and then turn the stop lamp switch on and off
again a further 10 times.
NOTE
If the functioning of the ABS-ECU has been stopped by the
fail-safe function, the diagnosis codes cannot be erased.
With-
in 1 s With-
in 1 s
With-
in 1 s
With-
in 1 s
With-
in 1 s
With-
in 1 s With-
in 1 s
With-
in 1 s
With-
in 1 s With-
in 1 s
Within 3 s
1st 2nd 3rd 4th 5th 6th 7th 8th
9th
10th Erasing
complete
Ignition switch ON
LOCK (OFF)
Stop lamp switch ON
OFF
ABS warning
lamp
ON
OFF
Trouble code memory
1s
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ABS <4WD> - Troubleshooting 35B-7
INSPECTION CHART FOR DIAGNOSIS CODES
Diagnosis code
No.
Diagnosis item Reference page
11 Wheel speed sensor (FR) system (open circuit or short- circuit) 35B-8
12 Wheel speed sensor (FL) system (open circuit or short- circuit) 35B-8
13 Wheel speed sensor (RR) system (open circuit or short-circuit) 35B-8
14 Wheel speed sensor (RL) system (open circuit or short- circuit) 35B-8
15 Wheel speed sensor system (output signal abnormality) 35B-9
16 ABS-ECU or valve relay power supply system (abnormal voltage
drop or rise)
35B-10
21 Wheel speed sensor (FR) system 35B-8
22 Wheel speed sensor (FL) system 35B-8
23 Wheel speed sensor (RR) system 35B-8
24 Wheel speed sensor (RL) system 35B-8
26 Center differential lock switch system 35B-11, 12
27 Rear differential lock switch system 35B-11, 12
32 G sensor system 35B-13
33 Stop lamp switch system 35B-14
41 Control solenoid valve (FR)
system
If there is no response to the
solenoid valve drive signal
35B-15
42 Control solenoid valve (FL)
system
corresponding to each respec-
tive item
43 Control solenoid valve (RR)
system
44 Control solenoid valve (RL)
system
45 Changeover solenoid valve
(FR) system
46 Changeover solenoid valve
(FL) system
51 Valve relay system (ON problem) 35B-16
52 Valve relay system (OFF problem) 35B-17
55 HBB system Carry out HBB troubleshoot-
ing. (Refer to GROUP 35A.)
63 ABS-ECU system 35B-32 (ABS-ECU replace-
ment)
NOTE
*: Code No.16 is erased from the memory if the condition returns to normal.
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ABS <4WD> - Troubleshooting ABS <4WD> - Troubleshooting
35B-8
INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSIS CODE
Code No. 11, 12, 13, 14 Wheel speed sensor system
(open circuit or short-circuit)
Probable cause
Code No. 21, 22, 23, 24 Wheel speed sensor system
Code Nos. 11, 12, 13, 14 are output when the open circuit or short-circuit
detection carried out by the ABS-ECU hardware circuit detects that there is an
open circuit or short-circuit in the (+) or ( - ) wire in one of the four wheel speed
sensors and signals are consequently not being input.
DMalfunction of wheel speed sensor
DMalfunction of harness or connector
DMalfunction of the ABS-ECU
Code No. 21, 22, 23, 24 are output at the following times:
DIf an open circuit cannot be verified, but one or more of the wheel speed
sensors does not output any signal when the vehicle speed is a certain
number of km/h or higher.
DWhen a problem such as chipped or plugged- up rotor tooth is detected, or if
the sensor output drops and anti- skid control is continuously carried out due
to a malfunctioning sensor or a warped ABS rotor.
DMalfunction of wheel speed sensor
DMalfunction of harness or connector
DMalfunction of ABS rotor
DExcessive clearance between sensor and ABS
rotor
DMalfunction of the ABS-ECU
DMalfunction of wheel bearing
NG
NG
Replace the ABS-ECU.
NG
Repair
OK
Check the trouble symptoms.
OK
Check the following connector: E-106
OK
Wheel bearing check
(Refer to GROUP 26, 27 -
On-vehicle Service.)
NG
Replace
OK
ABS rotor check
(Refer to P.35B-33.)
NG
Replace
Wheel speed sensor check
(Refer to P.35B-34.)
OK
Wheel speed sensor output voltage check (Refer to P.35B-27.)
OK
Check the following connectors: A-04 <L.H.D.>, A-23, A-39,
D-124, D-143 <R.H.D.>, E-10, E-106, F-17, G-11, G-15
Wheel speed sensor installation check NG Repair
OK
Measure at ABS-ECU connector E-106.
DDisconnect the connector and measure at the harness
side.
DFront: resistance between 10 – 23, 7 – 20
Rear: resistance between 8 – 21, 9 – 22
OK: 1.0 - 1.5 kW
NG
NG
Replace
NG
Repair
OK
Check the trouble
symptoms.
NG
Check the harness wire, and repair if necessary.
DBetween each wheel speed sensor and ABS-ECU
Wheel speed sensor check (Refer to P.35B-34.)
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ABS <4WD> - Troubleshooting 35B-9
Code No. 15 Wheel speed sensor system (output signal
abnormality)
Probable cause
This malfunction code is output when any one of the wheel speed sensor output
signals during driving is abnormal (except open and short circuit).
DUneven tyre size for all four wheels
DIncorrect wheel speed sensor installation
DMalfunction of wheel speed sensor
DMalfunction of harness or connector
DMalfunction of ABS rotor
DMalfunction of wheel bearing
DMalfunction of the ABS-ECU
NG
Check the harness wire, and repair if necessary.
DBetween each wheel speed sensor and ABS-ECU
OK
Wheel bearing check
(Refer to GROUP 26, 27 - On-vehicles Service.
NG
Replace
OK NG
Replace
NG
Replace the ABS - ECU.
OK
Check the trouble
symptoms.
NG
Repair
OK
Check the following connector: E-106
OK
Wheel speed sensor output voltage check (Refer to P.35B-27.)
NG Wheel speed sensor check (Refer to P.35B-34.)
NG
Wheel speed sensor installation check NG Repair
Are the tyres on all four wheels of identical size?
NO
Fit tyres which are of identical size.
YES
Check the trouble symptoms.
Check the ABS rotor (Refer to P.35B-33).
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ABS <4WD> - Troubleshooting
35B-10
Code No.16 ABS-ECU power supply system (abnormal
voltage increase or decrease)
Probable cause
This code is output if the ABS-ECU power supply voltage or valve relay power
supply voltage drops below or rises above a certain level.
DMalfunction of battery
DMalfunction of harness or connector
DMalfunction of the ABS-ECU
Caution
If the system voltage drops or rises during inspection, this code will be output to indicate a current
problem. And correct problem diagnosis will not be possible. Before carrying out the following
procedure, check the battery and recharge it if necessary.
OK NG
Repair
OK
(1)NG
Check the following connectors: D-32 <R.H.D.>, D-128,
D-208, D-210 <R.H.D.>, D-213 <L.H.D.>, E-08 <Diesel>, E-13,
E-106
NG
Check the harness wire, and repair if necessary.
DBetween the ignition switch and the ABS-ECU
(2)NG
OK
Check the trouble symptoms.
NG
Repair
NG
Check the harness wire, and repair if necessary.
DBetween the ignition switch and the ABS-ECU
Check the following connectors: E-13, E-107
Measure at E-106, E-107 ABS-ECU connectors.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
(1) Voltage between terminal 13 and body earth
OK: System voltage
(2) Voltage between terminal 31 and body earth
OK: System voltage
NG
(1)NG
Check the ABS valve relay (Refer to P.35B-28).
NG
Replace the ABS valve relay.
OK
Check the harness wire, and repair if necessary.
DBetween ignition switch and ABS valve relay
OK
Repair
OK
Replace the ABS-ECU.
Check the trouble symptoms.
Check the following connectors: B-21X, D-32 <R.H.D.>,
D-128, D-208, D-210 <R.H.D.>, D-213 <L.H.D.>, E-13
OK
NG
(2)NG
Check the harness wire, and repair if necessary.
DBetween fusible link No. 8 and the ABS valve relay
OK NG
Repair
NG
Check the trouble symptoms.
Check the following connector: B-21X
OK
NG
OK NG
Repair
Check the harness wire, and repair if necessary.
DBetween ABS-ECU and ABS valve relay
NG
Check the trouble symptoms.
Check the following connectors: E-107, B-21X
OK
OK NG
Repair
Check the trouble symptoms.
Check the following connectors: B-17, B-18, B-21X, E-107
NG
Repair
Check the harness wire, and repair if necessary.
DBetween ABS valve relay and HBB and ABS-ECU terminal
(48)
Measure at ABS-ECU connector E-107.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
DVoltage between terminal 37 and body earth
OK: System voltage
Measure at ABS valve relay connector B-21X.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
(1) Voltage between 1 and body earth
OK: System voltage
(2) Voltage between terminal 5 and body earth
OK: System voltage
Check the trouble symptoms.
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ABS <4WD> - Troubleshooting 35B-11
<Vehicles without rear differential lock system>
Code No. 26 Center differential lock switch system Probable cause
Code No. 27 Rear differential lock switch system
The ABS-ECU is designed to accommodate the fitting of a rear differential lock.
Because of this, for vehicles which are not equipped with a rear differential lock,
system voltage is applied to terminal (33) of the ABS-ECU instead of the rear
differential lock switch signal. If there is an open circuit in the lines by which this
system voltage is applied, the ABS-ECU outputs code Nos. 26 and 27.
DMalfunction of harness or connector
DMalfunction of the ABS-ECU
NG
OK
Replace the ABS-ECU.
NG
Check the harness wire, and repair if necessary.
DBetween the ignition switch and the ABS-ECU
OK
NG
Repair
Measure at ABS-ECU connector E-107.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
DVoltage between terminal 33 and body earth
OK: System voltage Check the trouble symptoms.
Check the following connector: D-32, D-124, D-208, D-210,
E-13, E-107, F-17
OK NG
Repair
NG
Check the trouble symptoms.
Check the following connector: E-107
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ABS <4WD> -Troubleshooting
35B-12
<Vehicles with rear differential lock system>
Code No.26 Center differential lock detection switch Probable cause
Code No.27 Rear differential lock detection switch
On vehicles with rear differential lock system, these codes will be set under the
following conditions:
DThe ABS-ECU detects an open-circuit in the center differential lock detection
switch and the rear differential lock detection switch systems, so no signal is
sent.
DThe vehicle has been driven at 20 km/h or more for five minutes or more
while the center differential lock detection switch is off and the rear
differential lock detection switch is on, and then the vehicle speed decreases
to 2 km/h in that condition.
DMalfunction of harness or connector
DMalfunction of the center differential lock detection
switch
DMalfunction of the rear differential lock detection
switch
DMalfunction of the rear differential lock-ECU
DMalfunction of the ABS-ECU
YES
NGOK
Do the both of the center differential lock indicator lamp and the
rear differential lock indicator lamp illuminate normally?
YES Measure at the ABS-ECU connector E-107.
DDisconnect the connector, and measure at the harness side
connector.
DIgnition switch: ON
DVoltage between 33 and body earth
OK: System voltage
NGOK
NO
Does the center differential lock indicator lamp illuminate normally?
NO
Replace the center differ-
ential lock detection
switch. Check the following
connector: E-107
Check the following
connectors:
D-32<R.H.D.>,
D-124<L.H.D.>, E-13,
E-107
NG
Repair
Repair
Check the trouble symp-
tom
Check the trouble symp-
tom
OK
NG
NG
Check the harness wire,
and repair if necessary.
DBetween ABS-ECU
and rear differential
lock-ECU
Check the following
connectors:
C-16, E-107, E-113
NGOK
Repair
Check the trouble symp-
tom
NG
Check the harness wire.
DBetween ABS-ECU and center differential lock detection switch
NG
Repair
OK
Check the trouble symp-
tom
Replace the ABS-ECU.
Rear differential lock detection switch check
(Refer to GROUP 27)
NG
OK
Check the following connectors:
D-26, D-32<R.H.D.>, D-124, F-17, G-01, G-13
NG
Repair
OK
Check the trouble symptom
NG
Check the harness wire.
DBetween rear differential lock-ECU and rear differential lock
detection switch
NG
Repair
OK
Check the trouble symptom
NG
Replace the rear differential lock-ECU. NG
Replace the rear differen-
tial lock detection switch.
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ABS <4WD> - Troubleshooting 35B-13
Code No. 32 G sensor system Probable cause
This code is output at the following cases:
DWhen the G sensor output is lower than 0.5 V or higher than 4.5 V
(Open circuit or short-circuit in G sensor circuit)
DWhen there is no variation in the G sensor output voltage (G sensor output
seized)
DMalfunction of G sensor
DMalfunction of harness or connector
DMalfunction of the ABS-ECU
MB991348
OK
Replace the ABS-ECU.
NG
NG
Check the harness wire, and repair if necessary.
DBetween ignition switch and G sensor
OK
Check the trouble symptoms.
NG
Repair
OK
(1)NG Check the following connectors: D-32<L.H.D.>, D-208,
D-210, E-01, E-115
OK
Replace the G sensor.
NG
Check the harness wire, and repair if necessary.
DBetween the G sensor and ABS-ECU
OK
Check the trouble symptoms.
NG
Repair
(2)NG
Check the following connectors: E-01, E-106, E-113
OK
Replace the ABS-ECU.
NG
Repair
DRemove the G sensor (Refer to P.35B-36).
DConnect the special tool between the G sensor
harness-side connector E-01 and the G sensor.
DIgnition switch: ON
DVoltage between terminal 2 and body earth when the G
sensor is placed on a level surface
OK: 2.4 - 2.6 V
DVoltage between terminal 2 and body earth when the G
sensor is placed so that the label is facing straight up
OK: 3.3 - 3.7 V
Label
E-01
Harness- side
connector
OK
NG
Repair
NG
Check the following connectors: E-01, E-106, E-113
Check the trouble symptoms.
Repair
NG
Check the harness wire, and repair if necessary.
DBetween the G sensor and ABS-ECU
Label
Measure at G sensor connector E-01.
DDisconnect the connector and measure at the harness
side.
(1) Voltage between terminal 1 and body earth (Ignition switch:
ON)
OK: System voltage
(2) Continuity between terminal 3 and body earth
OK: Continuity
NG
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ABS <4WD> - Troubleshooting
35B-14
Code No. 33 Stop lamp switch system (open circuit or
ON problem)
Probable cause
This code is output at the following cases:
DIf the stop lamp switch is continuously on for 15 minutes or more while
driving
DIf there is an open circuit in the stop lamp switch input circuit harness
DMalfunction of stop lamp switch
DMalfunction of harness or connector
DMalfunction of ABS-ECU
OK
NG
Check the harness wire,
and repair if necessary.
DBetween stop lamp
switch and ABS-ECU
NG
Replace the ABS-ECU.
NG
Repair
Check the trouble
symptoms.
NG
Repair
OK
Check the trouble
symptoms.
NG
Check the following
connectors: D-26
<L.H.D.>, D-33 <L.H.D.>,
D-124 <R.H.D.>, D-128,
D-136, E-13, E-107
OK
Check the following
connector: E-107
NG
Check the harness wire, and repair if necessary.
DBetween fusible link No.2 and stop lamp switch
OK
OK
Check the following connectors: D-26 <L.H.D.>, D-27,
D-124 <R.H.D.>, D-136
OK
Does the stop lamp turn on and off normally?
NO
NG
Repair
NG
Replace
NG
Repair
YES
Measure at ABS-ECU connector E-107.
DDisconnect the connector and measure at the harness
side.
DStop lamp switch: ON
DVoltage between terminal 34 and body earth
OK: System voltage
Stop lamp switch installation check
(Refer to 35A - On-vehicle Service.)
Check the trouble symptoms.
Stop lamp switch check
(Refer to GROUP 35A - Brake Pedal.)
OK
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ABS <4WD> - Troubleshooting 35B-15
Code No. 41, 42, 43, 44 Control solenoid valve system Probable cause
Code No. 45, 46 Select solenoid valve system
The ABS-ECU constantly monitors the solenoid valve drive circuits. These codes
are output if the ABS- ECU judges that there is an open circuit or short- circuit in
a solenoid coil or harness because the solenoid valve is on but no current flows
to the solenoid valve, or if current continues flowing to the solenoid valve even
thought the solenoid valve is off.
DMalfunction of harness or connector
DMalfunction of HBB’s master cylinder and hydraulic
unit assembly
DMalfunction of the ABS-ECU
NG
NG
OK
Repair
NG
Replace the HBB’s master cylinder and hydraulic unit
assembly.
OK
Check the following connectors: B-18, B-21X
Check the harness wire, and repair if necessary.
DBetween HBB and ABS valve relay
OK
Check the trouble
symptoms.
NG
Repair
OK
OK
Replace the ABS-ECU.
Repair
Measure at HBB connectors B-16, B-17, B-18.
DDisconnect the connectors and measure at the HBB side.
DControl solenoid valve IN: Resistance between terminals 34
- 19 (FR), 34 - 21 (FL), 34 - 13 (RL) and 34 - 15 (RR)
OK: 4.75 - 5.25 W
DControl solenoid valve OUT: Resistance between terminals
34 - 20 (FR), 34 - 22 (FL), 34 - 14 (RL) and 34 - 16
(RR)
OK: 2.0 - 2.4 W
DSelect solenoid valves: Resistance between terminals 34 -
18 (FR) and 34 - 17 (FL)
OK: 3.5 - 3.9 W
DValve relay monitor: Continuity between terminals 34 - 3
OK: Continuity (approx. 33 W)
NG
Check the following connectors: B-16, B-17, E-106, E-107
Check the trouble symptoms.
NG
Check the harness wire between the HBB (solenoid valve,
valve relay monitor) and the ABS-ECU.
Measure at HBB connector B-18 and ABS valve relay
connector B-21X.
DDisconnect the connectors and measure at the harness
side.
DContinuity between terminal 34 (HBB side) and terminal 2
(valve relay side)
OK: Continuity
NG
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ABS <4WD> - Troubleshooting
35B-16
Code No. 51 Valve relay system (ON problem) Probable cause
This code is output when the ABS-ECU judges during the initial check when the
ignition switch is turned to the ON position and the valve relay is OFF that there
is a fused relay contact or a short-circuit in the valve relay drive circuit when
power is being supplied to the solenoid valve.
DMalfunction of harness or connector
DMalfunction of ABS valve relay
DMalfunction of the ABS-ECU
Repair
NG
Check the ABS valve relay (Refer to P.35B-28).
NG
Replace the ABS valve relay.
OK
Check the harness, and repair if necessary.
DBetween ABS valve relay and ABS-ECU
OK NG
Repair
OK
Replace the ABS-ECU.
Check the trouble
symptoms.
Check the following connectors: E-107, B-21X
OK
NG
NG
Check the harness, and repair if necessary.
DBetween ABS valve relay and HBB and ABS-ECU terminal
No.48
DBetween ABS valve relay and body earth
Measure at ABS-ECU connector E-107.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
DVoltage between terminal 37 and body earth
OK: System voltage
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ABS <4WD> - Troubleshooting 35B-17
Code No. 52 Valve relay system (OFF problem) Probable cause
This code is output if the ABS-ECU judges that there is a valve relay OFF
problem when the valve relay is on and power is supplied to the solenoid valve.
DMalfunction of harness or connector
DMalfunction of ABS valve relay
DMalfunction of the ABS-ECU
NOTE
When reading the diagnosis codes using the ABS warning lamp (Refer to P.35B-5.), the valve relay
connector is disconnected during inspection, with the result that this problem code will be output in addition
to any other problem codes.
After the problem locations indicated by the problem diagnosis codes have been checked and repaired
but the ABS warning lamp remains illuminated and no diagnosis codes other than code No. 52 are displayed,
there is probably a malfunction of the valve relay system. In this case, carry out the following inspection.
NG
Repair
(1)NG
Check the ABS valve relay (Refer to P.35B-28).
NG
Replace the ABS valve relay.
OK
Check the harness wire, and repair if necessary.
DBetween ignition switch and ABS valve relay
OK
Repair
OK
Replace the ABS-ECU.
Check the trouble symptoms.
Check the following connectors: B-21X, D-32 <R.H.D.>,
D-128, D-208, D- 210 <R.H.D.>, D-213 <L.H.D.>, E - 13
OK
NG
NG
Check the harness wire, and repair if necessary.
DBetween ABS valve relay and HBB and ABS-ECU terminal
No. 48
(2)NG
Measure at ABS valve relay connector B-21X.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
(1) Voltage between 1 and body earth
OK: System voltage
(2) Voltage between terminal 5 and body earth
OK: System voltage
Check the harness wire, and repair if necessary.
DBetween fusible link No. 8 and the ABS valve relay
OK NG
Repair
NG
Check the trouble symptoms.
Check the following connector: B-21X
OK
NG
Measure at ABS-ECU connector E-107.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
DVoltage between terminal 37 and body earth
OK: System voltage OK NG
Repair
Check the harness wire, and repair if necessary.
DBetween ABS-ECU and ABS valve relay
NG
Check the trouble symptoms.
Check the following connectors: E-107, B-21X
OK
OK NG
Repair
Check the trouble symptoms.
Check the following connectors: B-17, B-18, B-21X, E-107
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ABS <4WD> - Troubleshooting
35B-18
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble Symptom Inspection
procedure
No.
Reference
page
Communication with MUT-II is not possible. 135B-18
Communication with MUT-II and the ABS-ECU is not possible. 235B-19
The ABS warning lamp does not illuminate when the ignition key is turned to ON (engine
stopped).
335B-20
The ABS warning lamp remains illuminated after the engine has started. 435B-20
The brake warning lamp does not illuminate when the ignition switch is turned ON (engine
stopped).
Refer to GROUP 35A.
The brake warning lamp remains illuminated after the engine has started.
Abnormal brake operation 535B-21
Caution
(1) Because the ABS may also operate at times when sudden braking is not being carried out,
such as when driving on low frictional coefficient roads, when turning at high speed or during
high-speed overtaking, check with the customer that the problems are not occurring when
driving under conditions such as these.
(2) When the ABS is operating, changes in the brake pedal feel (vibration and difficulty depressing
the pedal) may occur. This happens because the hydraulic pressure inside the brake line is
continually changing in order to stop the wheels from locking up, and is not a malfunction.
INSPECTION PROCEDURES FOR TROUBLE SYMPTOMS
Inspection procedure 1
Communication with MUT-II is not possible. Probable cause
The cause is probably a malfunction of the diagnosis connector power supply
circuit or earth circuit.
DMalfunction of diagnosis connector
DMalfunction of harness or connector
NG Check the following connectors: D-23, D-27, D-210, D-211
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness wire, and repair if necessary.
DBetween battery and diagnosis connector
OK
NG
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness wire, and repair if necessary.
DBetween diagnosis connector and earth
OK
NG
Replace the MUT-II.
Measure at diagnosis connecter D-23.
DVoltage between 16 and body earth
OK: System voltage
Check the following connector: D-23
Measure at diagnosis connecter D-23.
DContinuity between terminals 4, 5 and body earth
OK: Continuity
Check the trouble symptoms.
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ABS <4WD> - Troubleshooting 35B-19
Inspection procedure 2
Communication with MUT-II and the ABS-ECU is not
possible.
Probable cause
The cause is probably an open circuit in the ABS-ECU power supply circuit or
an open circuit in the diagnosis output circuit.
DBlown fuse
DMalfunction of harness or connector
DMalfunction of the ABS-ECU
(1)NG
OK
Check the following connectors: E-13, E-107
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness wire, and repair if necessary.
DBetween ABS-ECU and diagnosis connector
OK
Check the following connectors: D-32 <R.H.D.>, D-128,
D-208, D-210 <R.H.D.>, D-213 <L.H.D.>, E-08 <Diesel>, E-13,
E-106
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness wire, and repair if necessary.
DBetween the ignition switch and the ABS-ECU
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness, and repair if necessary.
DBetween the ignition switch and the ABS-ECU
OK
NG
Repair
OK
NG
Replace the ABS-ECU.
Measure at diagnosis connector D-23 and ABS-ECU connector
E-107.
DDisconnect the connectors and measure at the harness
side.
DContinuity between the following terminals:
Between terminals 47 (ABS-ECU side) and 1 (diagnosis
connector side)
Between terminals 36 (ABS-ECU side) and 7 (diagnosis
connector side)
OK: Continuity
NG
Check the following connectors: D-23, D-33, D-128, D-222,
E-13, E-107
Check the trouble
symptoms.
Check the following connectors: E-106, E-107
(2)NG
Measure at ABS-ECU connectors E-106, E-107.
DDisconnect the connectors and measure at the harness
side.
DIgnition switch: ON
(1) Voltage between terminal 13 and body earth
OK: System voltage
(2) Voltage between terminal 31 and body earth
OK: System voltage
OK
Check the following connectors: E-106, E-107
Repair
OK
Check the trouble
symptoms.
NG
Check the harness wire, and repair if necessary.
DBetween the ABS-ECU and earth
NG
NG
Measure at ABS-ECU connectors E-106, E-107.
DDisconnect the connectors and measure at the harness
side.
DContinuity between terminals 12, 25, 26 and 42 and body
earth
OK: Continuity
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