Mitsubishi Grandis. Manual — part 906

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-39

STEP 4. Check ABS-ECU connector A-03 for
loose, corroded or damaged terminals, or
terminals pushed back in the connector.

Q: Is the check result normal?

YES :

An open or short circuit may be present in

the solenoid valve power supply circuit.
Repair the wiring harness between
ABS-ECU connector A-03 terminal 1 and
fusible link No.3. Then go to Step 8.

NO :

Repair or replace the damaged
component(s). Then go to Step 8.

STEP 5. Resistance measurement at ABS-ECU
connector A-03.

(1) Disconnect the connector A-03, and connect

special tool ABS Check Harness (MB991974) to
the wiring harness-side connector.
NOTE: Do not connect special tool ABS Check
Harness (MB991974) to the ABS-ECU.

(2) Measure the resistance between terminal 26 and

earth.

OK: 2 ohm or less

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Go to Step 6.

AC312621

Oil reservoir

Connector: A-03

AC

A-03

Hydraulic unit
(with built-in ABS-ECU)

A-03 Harness connector
(harness side)

AC312620AH

Oil reservoir

Connector: A-03

ABS-ECU

MB991974

Check connector

A-03 Harness connector

A-03

Hydraulic unit
(with built-in ABS-ECU)

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-40

STEP 6. Check ABS-ECU connector A-03 for
loose, corroded or damaged terminals, or
terminals pushed back in the connector.

Q: Is the check result normal?

YES :

An open circuit may be present in the earth

circuit. Repair the wiring harness between
ABS-ECU connector A-03 terminal 1 and
the body earth. Then go to Step 8 .

NO :

Repair or replace the damaged
component(s). Then go to Step 8.

STEP 7. Check whether the diagnosis code is
reset.

Check again if the diagnosis code is set.
(1) Turn the ignition switch to the "ON" position.
(2) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF)

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is code No.C1226, C1231, C1236, C1241, C1246,

C1251, C1256 or C1261 set?

YES :

Replace the hydraulic unit (integrated with

ABS-ECU). Then go to Step 8.

NO :

It can be assumed that this malfunction is
intermittent. Refer to GROUP 00, How to
Use Troubleshooting/Inspection Service
Points

− How to Cope with Intermittent

Malfunction

P.00-5

.

AC312621

Oil reservoir

Connector: A-03

AC

A-03

Hydraulic unit
(with built-in ABS-ECU)

A-03 Harness connector
(harness side)

AC302297

AC310120

AB

MB991827

16-pin

MB991910

MB991824

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-41

STEP 8. Check whether the diagnosis code is
reset.

Check again if the diagnosis code is set.
(1) Turn the ignition switch to the "ON" position.

(2) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF)

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is code No.C1226, C1231, C1236, C1241, C1246,

C1251, C1256 or C1261 set?

YES :

Go to Step 1.

NO :

The procedure is complete.

AC302297

AC310120

AB

MB991827

16-pin

MB991910

MB991824

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-42

Code No. C1271: Motor drive circuit (Abnormal power supply voltage)

CAUTION

If there is any problem in the CAN bus lines, an
incorrect diagnosis code may be set. Diagnose
the CAN bus lines before the Diagnosis codes
(Refer to GROUP 54D, CAN bus-line diagnostic
flow

P.54D-9

).

OPERATION

• The ABS-ECU contains the power supply circuit

(terminal 14) for the pump motor. The pump
motor is energized by the motor switch, which is
incorporated in the ABS-ECU.

• The pump motor switch, which is incorporated in

the ABS-ECU, is always off unless the motor
solenoid valve check is activated when the
vehicle is started.

• The ABS-ECU activates the pump motor by

turning on the ECU built-in pump motor switch
when the ABS is working.

DIAGNOSIS CODE SET CONDITIONS

The most likely causes for these diagnosis codes to
set are:

• This code is set if the pump motor power supply

voltage is abnormally low for long time when the
pump motor does not operate.

• This code is set if the pump motor voltage is

abnormally high for long time when the pump
motor does not operate.

• This code is set if the pump motor switch voltage

drop indicates high value when the pump motor
operates.

3

FUSIBLE
LINK

4

FUSIBLE
LINK

ABS-ECU

SOLENOID
VALVE POWER
SOURCE

SOLENOID
VALVE POWER
SOURCE

SOLENOID VALVE

HYDRAULIC UNIT

MOTOR
POWER
SOURCE

MOTOR
POWER
SOURCE

Wire colour code
B : Black LG : Light green G : Green L : Blue
W : White Y : Yellow SB : Sky blue BR : Brown
O : Orange GR : Gray R : Red P : Pink V : Violet

Solenoid Valve and Motor Power Supply Circuit