4WD MITSUBISHI MONTERO 2000 Service Owner's Manual

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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ABS <4WD> -Troubleshooting35B-18
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble SymptomInspection
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 operation535B-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
NGCheck 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> -Troubleshooting35B-19
Inspection procedure 2
Communication with MUT-II
and the ABS-ECU is not
possible.
Probable cause
The cause is probably anopencircuit in the ABS-ECU power supply circuit or
an opencircuit 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 , D-128,
D-208, D-210 , D-213 , E-08 , E-13,
E-106
NG
Repair OKCheck 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:ContinuityNGCheck 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 earthNG 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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ABS <4WD> -Troubleshooting35B-20
Inspection procedure 3
The ABS warning lamp does not illuminate when the
ignition key is turned to ON (engine stopped).
Probable cause
When power is first supplied to the ABS-ECU, the ABS-ECU turns the ABS-ECU
valve relay from off to on, off and back to onagain aspart of its initial check.
Accordingly, if the ABS warninglampdoes not illuminate, the cause is probably
an opencircuit in the ABS warninglamppower supply circuit, a blownlamp bulb
or an opencircuit between the ABS warninglamp and theABS-ECU.DBlown fuse
DBlown ABS warninglamp bulb
DMalfunction of ABS valve relay
DMalfunction of harness or connector
DMalfunction of combination meter
DMalfunction of the ABS-ECU
NG
Replace the combination meter.
NG
Repair
OK
NG
Check for a blown bulb.Replace the ABS
warning lamp bulb.
OK
NG
Repair
OK
Check the trouble symptoms.
Multi - purpose fuse No. 6 checkNGRefer to GROUP 00 – Inspection service Points for Blown
Fuse.
NG
Check the harness wire.
DBetween ignition switch and combination meter
DBetween the combination meter and the ABS-ECU
OK
OK
After replacing the ABS-ECU, carry out the following check.
DCheck the harness wire between the ABS warning lamp,
ABS valve relay and earth.
Check the following connector:E-107
NG
RepairCheck the trouble symptoms.OK
NG
Check the following connectors:D-01, D-208, D-210
, D-213 , E-10, E-107
Measure at the ABS-ECU connector E-107.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
DWarning lamp conditionwhen terminal 50 is shorted to
body earth
OK:Illuminates
Inspection procedure 4
The ABS warning lamp remains illuminated after the
engine has started.
Probable cause
The cause is probably a short-circuit in the ABS warninglamp illuminationcircuit.DMalfunction of combination meter
DMalfunction of harness (short-circuit)
DMalfunction of the 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.
When the ABS valve relay connector B-21X and the
ABS-ECU connector E-107 are disconnected and the ignition
switch is turned to the ON position, does the ABS warning
lamp remain illuminated?YES
NO
Replace the ABS-ECU.
Replace the combination meter.
NG
Repair
OK
Check the harness wire.
DBetween the ABS warning lamp, the ABS-ECU and the
ABS valve relay


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ABS <4WD> -Troubleshooting35B-21
Inspection procedure 5
Abnormal brake operation
Probable cause
Braking operation variesdepending on the driving conditions and the road
surface, which can make it difficult to diagnose a problem. However, if the
diagnosis codes displayed are normal, carry out the following inspection
procedure.DIncorrect wheel speed sensor installation
DMalfunction of harness or connector
DMalfunction of wheel speed sensor
DMalfunction of ABS rotor
DForeign material adhering to speed sensor
DMalfunction of wheel bearing
DMalfunction of HBB
DMalfunction of the ABS-ECU
Wheel speed sensor installation checkNG
Repair
OKCheck the hydraulic unit inside the hydraulic brake booster
(HBB). (Refer to P.35B-29.)
NG
Check the wheel speed sensor (Refer to P.35B-34.)NG
OK
Check the ABS rotor (Refer to P.35B-33).NG
Replace
OK
NG
Replace
OK
NG
Repair
OK
NG
NG
OK
Check the following connector:E-106
OK
Check the trouble symptoms.
NG
Replace the ABS-ECU.NG
Repair
Check the harness, and repair if necessary.
DBetween each wheel speed sensor and ABS-ECU ReplaceMeasure 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
W
(Move the sensor harness and connector while checking at
this time.)
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 bearing check
(Refer to GROUP 26, 27 - On-vehicle Service.)
Check the trouble symptoms.
Wheel speed sensor output voltage check (Refer to P.35B-27.)OK


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ABS <4WD> -Troubleshooting35B-22
DATA LIST REFERENCE TABLE
The following ECU input data items can be read using the MUT-II
.
(1) When system is normal
Item
No.Check itemInspection conditionsNormal condi-
tion
11Front - right wheel
speedWhen vehicle is being drivenSpeedometer
display and
12Front - left wheel
speedMUT-IIdisplay
are identical.
13Rear - right wheel
speed
14Rear - left wheel
speed
16System voltageIgnition switch: ON6.5 - 22.3 V
26Center differential
lock switchIgnition switch: ONTransfer selector lever position:
2H, 4HOFF
Transfer selector lever position:
4HLc, 4LLcON
27Rear differential lock
switchIgnition switch: ONOFF
32G sensorD
Ignition switch: ON
D
When vehicle is stationary (level)2.4 - 2.6 V
When vehicle is being driven1.0 - 4.0 V
33Stop lampIgnition switch: ONWhen brake pedal is depressedON
SwitchWhen brake pedal is releasedOFF
(2) When system is interrupted by the ECU
When the diagnosis function has caused the operation of the ABS-ECU to be stopped, the
MUT-II
display data may be different from the actual condition.
ACTUATOR TEST TABLE
The following actuators can be force-driven using the MUT-II
.
NOTE
(1) Actuator tests cannot be carried out when the operation of the ABS-ECU has been stopped by
the fail-safe function.
(2) Actuator tests can only be carried out while the vehicle is stopped.
ACTUATOR TEST SPECIFICATIONS
Item No.Check itemDrive Contents
01FR wheel solenoid valveHBB select solenoid valves and control solenoid valves for the
02FL wheel solenoid valverespective channel
03RR wheel solenoid valve
04RL wheel solenoid valve
27Air bleeding (1)HBB select solenoid valves and control solenoid valve OUT (FR, FL)
28Air bleeding (2)HBB control solenoid valve OUT (RR, RL)


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ABS <4WD> -Troubleshooting35B-25
Termi-
nal
No.Normal condition Inspection conditions Check item
37ABS valve relay outputIgnition
switch: ONWhen system abnormality is
detected and relay is offSystem voltage
When relay is on approx. 1
second after engine starts2 V or less
39Brake warning lamp outputIgnitionWhen lamp is switched off2 V or less
switch: ONWhen lamp is illuminatedSystem voltage
40Control solenoid valve OUT (RL)Ignition switch: ONSystem voltage
41Control solenoid valve OUT(FR)Ignition switch: ONSystem voltage
46Center differential lock switch
input Ignition
switch: ONTransfer selector lever position:
2H, 4HSystem voltage
Transfer selector lever position:
4HLc, 4LLc2 V or less
4WD detection switch input
Ignition
switch: ONTransfer selector lever position:
2HSystem voltage
Transfer selector lever position:
4H2 V or less
47Diagnosis select inputWhen the MUT-IIis connected1 V or less
When the MUT-IIis not connectedApprox. 12 V
48Valve relay monitorIgnition switch: ONSystem voltage
50ABS warning lamp outputIgnitionWhen lamp is switched offSystem voltage
switch: ONWhen lamp is illuminated2 V or less
51Control solenoid valve IN (RL)Ignition switch: ONSystem voltage
52Control solenoid valve IN (FR)Ignition switch: ONSystem voltage


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ABS <4WD> -On-vehicle Service35B-31
WHEN THE BATTERY IS FLAT
If the engine is started using a booster cable when the battery
is completely flat, and the vehicle is then driven without waiting
for the battery to be recharged, the engine may misfire and it
may not be possible to drive the vehicle. This is because the
ABS consumes a large amount of current when carrying out its
initial checks. If this happens, recharge the battery fully.
Caution
The vehicle posture will be unstable during braking, so
do not drive the vehicle with the ABS-ECU connector
disconnected or with the ABS not operating for any other
reason.


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