MITSUBISHI MONTERO 2000 Service Repair Manual

ABS <4WD> -TroubleshootingABS <4WD> -Troubleshooting35B-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 theopencircuit or short-circuit
detection carried out by the ABS-ECU hardware circuit detects that there is an
opencircuit or short-circuit in the (+) or ( - ) wire in one of the four wheel speed
sensors and signals are consequently notbeing 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 opencircuit 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 orplugged - uprotor 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 clearancebetween 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 , A-23, A-39,
D-124, D-143 , E-10, E-106, F-17, G-11, G-15
Wheel speed sensor installation checkNG
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 k
WNG
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> -Troubleshooting35B-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 (exceptopen andshort 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
OKNG
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.)NGWheel speed sensor check (Refer to P.35B-34.)
NG
Wheel speed sensor installation checkNG
Repair
Are the tyres on all four wheels of identical size?NOFit 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> -Troubleshooting35B-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 beoutput 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.
OKNG
Repair
OK
(1)NGCheck the following connectors:D-32 , D-128,
D-208, D-210 , D-213 , E-08 , 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).NGReplace 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 ,
D-128, D-208, D-210 , D-213 , 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
NGCheck 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 relayNG
Check the trouble symptoms.
Check the following connectors:E-107, B-21X
OK
OK
NG
RepairCheck 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> -Troubleshooting35B-11

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 notequippedwith a rear differential lock,
system voltage isapplied to terminal(33) of the ABS-ECU instead of the rear
differential lock switch signal. If there is anopencircuit 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>-Troubleshooting35B-12

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 hasbeendriven 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
NG OK
Do the both of the center differential lock indicatorlamp and the
rear differential lock indicatorlamp illuminate normally?YESMeasure 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
NG OK
NO
Does the center differential lock indicatorlamp illuminate normally?
NO
Replace the center differ-
ential lock detection
switch.
Check the following
connector:E-107Check the following
connectors:
D-32,
D-124, E-13,
E-107
NG
Repair
Repair
Check the trouble symp-
tom
Check the trouble symp-
tomOKNG
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
NG OK
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, 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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P
ro bab le cau se R
epla ce th e ABS-E C U. N
G N
G C
heck th e harn ess wir e , and re pair if nece ssa ry .
D B
etw een ig nit io n sw it c h and G se nso r O
K C
heck th e tr o uble sym pto m s. N
G
R ep air (
1 )N G O
K R
epla ce th e G se nso r. N
G C
heck th e harn ess wir e , and re pair if nece ssa ry .
D B
etw een th e G se nso r and ABS-E C U O
K C
heck th e tr o uble sym pto m s. N
G
R ep air O
K R
epla ce th e ABS-E C U. N
G
R ep air C
heck th e tr o uble sym pto m s.
Rep air C
heck th e harn ess wir e , and re pair if nece ssa ry .
D B
etw een th e G se nso r and ABS-E C U L
abel

ABS <4WD> -Troubleshooting35B-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 stoplampswitch is continuously on for 15 minutes or more while
driving
DIf there is an opencircuit in the stoplampswitch input circuit harnessDMalfunction of stoplampswitch
DMalfunction of harness or connector
DMalfunction of ABS-ECU
OK
NG
Check the harness wire,
and repair if necessary.
DBetween stoplamp
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
, D-33 ,
D-124 , 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 stoplampswitch
OK
OK
Check the following connectors:D-26 , D-27,
D-124 , D-136
OK
Does the stoplampturn 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.
DStoplampswitch: ON
DVoltage between terminal 34 and body earth
OK:System voltage
Stoplampswitch installation check
(Refer to 35A - On-vehicle Service.)
Check the trouble symptoms.
Stoplampswitch check
(Refer to GROUP 35A - Brake Pedal.)
OK


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ABS <4WD> -Troubleshooting35B-15
Code No. 41, 42, 43, 44 Control solenoid valve systemProbable 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 opencircuit 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:ContinuityNG


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ABS <4WD> -Troubleshooting35B-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 isbeing supplied to the solenoidvalve.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).NGReplace the ABS valve relay.
OK
Check the harness, and repair if necessary.
DBetween ABS valve relay and ABS-ECU
OKNG
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> -Troubleshooting35B-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).NGReplace 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 ,
D-128, D-208, D - 210 , D-213 , 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
NGCheck 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 relayNG
Check the trouble symptoms.
Check the following connectors:E-107, B-21X
OK
OK
NG
RepairCheck the trouble symptoms.
Check the following connectors:B-17, B-18, B-21X, E-107


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