MITSUBISHI TRITON 1997 Workshop Manual

ABS <2WD> ± Troubleshooting35B-8
Code No. 15 Wheel speed sensor (Abnormal output signal)Probable cause
A wheel speed sensor outputs an abnormal signal (other than an open or short-circuit).
Improper installation of wheel speed sensor

Malfunction of wheel speed sensor

Malfunction of rotor

Malfunction of wheel bearing

Malfunction of wiring harness or connector

Malfunction of ABS-ECU
NG
Replace the ABS-ECU.
OK
Check trouble symptoms.
OK
Wheel bearing check. (Refer to GROUP
26 and 27 ± On-vehicle Service.)OKCheck the harness wire between each
wheel speed sensor and ABS-ECU, and
repair if necessary.
OK
Rotor check. (Refer to P.35B-40.)NGReplace the rotor.
OK
Check the following connector.
C-62NG
Repair
OK
Wheel speed sensor output voltage
check (Refer to P.35B-24.)NGWheel speed sensor check. (Refer to
P.35B-39.)NGReplace the wheel speed sensor.
Wheel speed sensor installation check.NG
Repair
Code No. 16 Power supply systemProbable cause
The voltage of the ABS-ECU power supply drops lower or rises higher than the specified
value. If the voltage returns to the specified value, this code is no longer output.
Malfunction of wiring harness or connector.

Malfunction of 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 distilled water if
necessary.
OK
Check the battery.
OK
Check trouble symptoms.NGCheck the harnes wire between the igni-
tion switch and the ABS-ECU, and repair
if necessary.
OK
Check trouble symptoms.NGReplace the ABS-ECU.
OK
Check the following connector.
C-62NG
Repair
Measure at the ABS-ECU connector
C-62.

Disconnect the connector and
measure at the harness side.

Start the engine. Voltage between
13 ± Body earth
OK:System voltageNGCheck the following connectors.
C-88, C-86 and C-02NG
Repair

ABS <2WD> ± Troubleshooting35B-9
Code No. 33 Stop lamp switch systemProbable cause
These codes are output at the following times:

When the stop lamp switch is not be turned off (when the stop lamp switch stays
on for 15 minutes or more although the ABS is not operating)

When the ABS-ECU determines that there is an open circuit in harness of the
stop lamp switch system.
Malfunction of stop lamp switch

Malfunction of harness or connector

Malfunction of ABS-ECU
OK
Check trouble symptom.
NG
Check the harness between dedicated
fuse No. 8 and the ABS-ECU, and repair
if necessary.
OK
Check the harness between dedicated
fuse No. 8 and the ABS-ECU, and repair
if necessary.
OK
Stop lamp switch check. (Refer to
GROUP 35A ± On-vehicle Service.)NGReplace the stop lamp switch.
OK
Check trouble symptom.NGReplace the ABS-ECU.
Does the stop lamp illuminate and switch
off normally?NoStop lamp switch installation check.NG
Repair
Ye s
Measure at ABS-ECU connector C-64.

Disconnect the connector and
measure at the harness side.

Stop lamp switch ON.

Voltage between 34 and body earth
OK:System voltageNGCheck the following connectors.
C-82, C-89, C-34 and C-02NG
Repair
OK
Check the following connector.
C-64NG
Repair

ABS <2WD> ± Troubleshooting35B-10
Code No. 41, 42, 43 Solenoid valveProbable cause
The ABS-ECU always monitors the solenoid valve drive circuit. It determines that
there is an open or short-circuit in the solenoid coil or in a harness: When no current
flows in the solenoid even though the ABS-ECU turns on it, and vice versa.
Malfunction of wiring harness

Malfunction of hydraulic unit

Malfunction of ABS-ECU
NG
Check the harness between the hydrau-
lic unit and ABS-ECU, and repair if nec-
essary.
OK
Check trouble symptoms.
Measure at hydraulic unit connector
A-09.

Disconnect the connector and
measure at the harness side.

Resistance values between the
following terminals
1-5, 2-5, 3-5
OK: 5.0 W
6-5, 7-5, 8-5
OK: 2.2 WNGReplace the hydraulic unit.
OK
Measure at hydraulic unit connector
A-09 and ABS-ECU connectors C-62
and C-64.

Disconnect the connector and
measure at the harness side.

Continuity between the following
terminals
OK:Continuity
HU side
ABS-ECU
side (C-64)
HU side
ABS-ECU
side (C-62)NGCheck the following connectors.
A-09, C-62 and C-64NG
Repair
OK
Measure at hydraulic unit connector
A-09 and valve relay connector A-39.

Disconnect the connector and
measure at the harness side.

Continuity between the following
terminals
OK:Continuity
HU side
Valve relay sideNGCheck the following connector and
diode.
A-09 and A-39NG
Repair
OK
Check trouble symptoms.NGCheck the harness between the hydrau-
lic unit and valve relay, and repair if nec-
essary.
OK
Check the following connectors.
C-62 and C-64NG
Repair
OK
Check trouble symptoms.NGReplace the ABS-ECU. 1
52
2
14 6
41
3
37
18
2
5
310
3

ABS <2WD> ± Troubleshooting35B-11
Code No. 51 Valve relayProbable cause
When the ignition switch is turned to ON, the ABS-ECU switches the valve relay
off and on during the initial check. In that way, the ABS-ECU compares the signals
sent to the valve relay with the voltage in the valve power monitor line. That is how
to check if the valve relay is operating normally. The ABS-ECU always checks if
current flows in the valve power monitor line, too. It determines that there is an open
circuit when no current flows. If no current flows in the valve power monitor line,
this diagnosis code is output.
Malfunction of valve relay

Malfunction of wiring harness or connector

Malfunction of ABS-ECU

Malfunction of hydraulic unit
NOTE
Whenever reading the diagnosis codes using the ABS warning lamp (Refer to GROUP 00 ± How to
Use Troubleshooting/Inspection Service Points), this diagnosis code will be output. That is not a malfunction
but because the valve relay connector is disconnected. After repairing all other malfunctions, connect
the valve relay connector again to check the valve relay. Then check that the ABS warning lamp does
not illuminate. If it illuminates, the valve relay may be defective. So carry out the following procedure.
Valve relay check. (Refer to P. 35B-28.)NGReplace the valve relay.
OK
Measure at valve relay connector A-39.

Disconnect the connector and
measure at the harness side.

Voltage between 6 ± body earth
OK:System voltageNGCheck the harness between fusible link
No. 11 and valve relay, and repair if nec-
essary.
OK
Measure at ABS-ECU connector C-62
and C-64.

Disconnect the connector and
measure at the harness side.

Resistance between 26 ± 37
OK:60 ± 120 WNGCheck the following connector.
A-39OKCheck trouble symptoms.
NG
Check the harness between valve relay
and ABS-ECU, and repair if necessary.
OK
Measure at ABS-ECU connector C-64.

Disconnect the connector and
measure at the harness side.

Continuity between 48 ± body earth
OK:ContinuityNGCheck the harness between the valve
relay and ABS-ECU, and repair if neces-
sary.
OK
Check the following connector.
C-64OKCheck trouble symptoms.NGReplace the ABS-ECU.

ABS <2WD> ± Troubleshooting35B-12
Code No. 53 Motor relay, motorProbable cause
These codes are output at the following times:
When the motor relay is on but no signal is input to the motor monitor line (motor
is not operating, etc.)
When the motor relay is off but a signal is input to the motor monitor line for 5 seconds
or more (motor continues operating, etc.)
When the motor relay does not operate
Malfunction of motor relay

Malfunction of wiring harness or connector

Malfunction of hydraulic unit

Malfunction of ABS-ECU
Caution
Because force-driving of the motor by means of the actuator test will drain the battery, the engine
should be started and left to run for a while after testing is completed.
NG
Repair
MUT-II Actuator test
Is the sound of the motor operating
heard for items 01 ± 03 only?Ye sCheck the harness between the hydrau-
lic unit and ABS-ECU, and repair if nec-
essary.
No
ABS motor relay check. (Refer to
P.35B-28.)NGReplace the motor relay.
OK
Measure at motor relay connector A-38.

Disconnect the connector and
measure at the harness side.

Voltage between 5 ± body earth
OK:System voltageNGCheck the harness between fusible link
No. 11 and ABS motor relay, and repair
if necessary.
OK
Measure at ABS-ECU connectors C-62
and C-64.

Disconnect the connector and
measure at the harness side.

Resistance between 26 ± 38
OK:72 ± 88 WNGCheck the following connector.
A-38
OK
Check trouble symptoms.NGCheck the harnesses between motor
relay and ABS-ECU, and repair if
necessary.
OK
Measure at ABS-ECU connector C-64.

Disconnect the connector and
measure at the harness side.

Continuity between 49 ± body earth
OK:ContinuityNGCheck the harness between the
hydraulic unit and ABS-ECU, and repair
if necessary. Motor earth, repair if
necessary.
OK
Motor operation check. (Refer to
P.35B-27.)NGReplace the hydraulic unit.
OK
Check the following connector.
C-64NG
Repair
OK
Check trouble symptoms.NGReplace the ABS-ECU.

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ABS <2WD> ± Troubleshooting35B-14
INSPECTION CHART FOR TROUBLE SYMPTOMS35201140142
Get an understanding of the trouble symptoms and check according to the inspection procedure chart.
Trouble symptomsInspection
procedure No.Reference
page
Communication with MUT-II
is notpossible
Communication with all systems is not possible.135B-15
is not ossible.
Communication with ABS only is not possible.235B-15
When the ignition key is turned to ªONº (engine stopped), the ABS warning lamp does
not illuminate.335B-16
After the engine starts, the ABS warning lamp remains illuminated.435B-16
When the ignition key is turned to ªSTARTº, the ABS warning lamp does not illuminate.535B-17
After the ignition key is turned to ªONº, the ABS warning lamp blinks twice, and when
turned to ªSTARTº, it illuminates. When returned to ªONº, the lamp flashes once, and
then switches off.635B-17
Faulty ABS operationUnequal braking power on both sides735B-18
Insufficient braking power
ABS operates under normal braking conditions
ABS operates before vehicle stops under normal
braking conditions
Large brake pedal vibration (Caution 2.)±±
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.

ABS <2WD> ± Troubleshooting35B-15
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
Inspection Procedure 1
Communication with MUT-II is not possible.
(Communication with all systems is not possible.)
Probable cause
The reason is probably a defect in the power supply system (including earth) for
the diagnosis line.
Malfunction of connector

Malfunction of harness
Refer to GROUP 13A ± Troubleshooting.
Inspection Procedure 2
Communication with MUT-II is not possible.
(Communication with ABS only is not possible.)
Probable cause
When communication with the MUT-II is not possible, the cause is probably an open
circuit in the ABS-ECU power circuit or an open circuit in the diagnosis output circuit.
Blown fuse

Malfunction of wiring harness or connecter

Malfunction of ABS-ECU
OK
Check trouble symptoms.NGReplace the ABS-ECU.
OK
Check the following connectors.
C-62 and C-64NG
Repair
OK
Check trouble symptoms.NGCheck the harness wire between the
ignition switch and the ABS-ECU, and
repair if necessary.
OK
Measure at ABS-ECU connectors C-62
and C-64

Disconnect the connector and
measure at the harness side.

Continuity between 4, 15, 16, 25
(C-62), 42 (C-64) ± body earth
OK:ContinuityNG
OK
Measure at ABS-ECU connector C-62

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Voltage between 13 ± body earth
OK:System voltageNGCheck the following connectors.
C-88, C-86 and C-02NG
Repair
OK
Check trouble symptoms.NGCheck the harness between the ABS-
ECU and diagnosis connector, and re-
pair if necessary.
Measure at diagnosis connector C-35
and ABS-ECU connector C-64

Disconnect the connector and
measure at the harness side.

Continuity between the following
terminals
OK:Continuity
ABS-ECU side
Diagnosis connector sideNGCheck the following connector.
C-02NG
Repair
Repair 47
1367

ABS <2WD> ± Troubleshooting35B-16
Inspection Procedure 3
When ignition key is turned to ºONº (engine stopped),
ABS warning lamp does not illuminate.
Probable cause
When current flows in the ABS-ECU, the valve relay turns from off to on, off and
back to on again as the initial check. So the ABS warning lamp will illuminate twice
when the valve relay is off even if there is a problem with the circuit between the
ABS warning lamp and the ABS-ECU.
Therefore, if the lamp does not illuminate, the cause may be: an open circuit in the
lamp power supply circuit, a blown lamp bulb, an open circuit in both the circuit between
the ABS warning lamp and the ABS-ECU and in the circuit between the ABS warning
lamp and the valve relay.
Blown fuse

Burnt out ABS warning lamp bulb

Malfunction of wiring harness or connector
OK
Check trouble symptoms.NGReplace the combination meter. NG
Repair
OK
Check the following connectors.
C-88, C-79, C-06, C-05 and C-02
OK
Check the harnesses between the valve
relay and connector C-02 and between
the ABS-ECU and connector C-02. Re-
pair if necessary.
OK
Measure at connector C-02:

Disconnect the connector and
measure at the male pin.

Ignition switch: ON

Does the ABS warning lamp
illuminate when terminal (3) is
earthed?
OK:IlluminatesNGCheck whether the ABS warning lamp
bulb is burnt out.NGReplace the ABS warning lamp bulb.
Fuse inspection, Multi-purpose fuse No.
11NGRefer to GROUP 00 ± Inspection Ser-
vice Points for a Blown Fuse.
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 of combination meter

Malfunction of ABS-ECU

Malfunction of wiring harness
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.
No
Check the harnesses between the combination meter and the ABS-
ECU and between the combination meter and the valve relay. Repair,
if necessary.
No

Disconnect ABS-ECU connector C-64.

Disconnect valve relay connector A-39.

Ignition switch: ON

Does the ABS warning lamp switch off?Ye sReplace the ABS-ECU.
Disconnect connector C-02 and turn the ignition switch to ON.

Does the ABS warning lamp remain illuminated?Ye sReplace the combination meter.

ABS <2WD> ± Troubleshooting35B-17
Inspection Procedure 5
When ignition key is turned to ºSTARTº, ABS warning
lamp does not illuminate.
Probable cause
Current does not flow in the ABS-ECU when the ignition switch is turned to START.
Current flows in the ABS warning lamp even when the ignition switch is turned to
START. Therefore, the valve relay, which current is supplied through the ABS-ECU,
turns off when the ignition switch is at START. However, the warning lamp circuit
of the valve relay must turn on in turn. So the cause must be a defective circuit
on valve relay side.
Malfunction of wiring harness or connector

Malfunction of ABS-ECU
ABS valve relay check (Refer to
P.35B-28.)NGReplace the ABS valve relay.
OK

Disconnect valve relay connector
A-39.

Disconnect ABS-ECU connector
C-64.

Ignition switch: ON

Voltage between valve relay
harness-side connector terminal (3)
and body earth
OK:System voltageNGCheck the following connector and
diode.
C-02 and C-05NG
Repair
OK
Check trouble symptoms.NGCheck the harness between the com-
bination meter and valve relay, and re-
pair if necessary.
OK
Check the following connector.
A-39NG
Repair
OK
Check trouble symptoms.NGCheck the harness between the valve
relay and earth, and repair if necessary.
Inspection Procedure 6
The ABS warning lamp flashes twice after the ignition key
is turned to ºONº. The lamp illuminates when the ignition
key is turned to ºSTARTº, and when the key is returned to
ºONº, it flashes once.
Probable cause
The ABS-ECU causes the ABS warning lamp to illuminate during the initial check
(approx. 3 seconds). During the initial check, the valve relay turns from off to on,
off and back to on again. If there is an open circuit in the harness between the ABS-ECU
and the ABS warning lamp, the lamp will illuminate only when the valve relay is OFF
during valve relay test, etc.
Malfunction of wiring harness or connector

Malfunction of ABS-ECU

Disconnect valve relay connector
A-39.

Disconnect ABS-ECU connector
C-64.

Ignition switch: ON

Voltage between ABS-ECU har-
ness-side connector terminal (50)
and body earth
OK:System voltageNGCheck the following connector.
C-02NG
Repair
OK
Check trouble symptom.NGCheck the harness between the com-
bination meter and the ABS-ECU, and
repair if necessary.
OK
Check the following connector.
C-64NG
Repair
OK
Check trouble symptom.NGReplace the ABS-ECU.