Mitsubishi Grandis. Manual — part 908

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-47

Code No.C1276: Valve system

OPERATION

• The ABS-ECU contains the power supply circuit

(terminal 1) for the solenoid valve. The solenoid
valve is energized by the valve relay, which is
incorporated in the ABS-ECU.

• The valve relay, which is incorporated in the

ABS-ECU, is always energizing the solenoid
valve unless the initial check is in progress when
the ignition switch is turned on, or the recurrent
system check is in progress.

DIAGNOSIS CODE SET CONDITIONS

These diagnosis codes will be set under the cases
below.

• The ABS-ECU monitors the power supply voltage

to the solenoid valve. If the voltage is lower than
the predetermined value, the ECU sets this
diagnosis code as a failure in the valve relay
circuit.

PROBABLE CAUSES

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

• Damaged wiring harness or connector

• Malfunction of the hydraulic unit (integrated with

ABS-ECU)

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

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-48

DIAGNOSIS

STEP 1. MUT-III CAN bus diagnostics

CAUTION

Before connecting or disconnecting the MUT-III,
turn the ignition switch to the "LOCK" (OFF)
position.
(1) Connect MUT-III to the 16-pin diagnosis

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the CAN bus line (Refer to GROUP
54D, CAN bus line Diagnostic flow

P.54D-9

). Then go to Step 2.

STEP 2. Check whether the diagnosis code is
reset.

CAUTION

Before connecting or disconnecting the MUT-III,
turn the ignition switch to the "LOCK" (OFF)
position.
(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.C1276 set?

YES :

Go to Step 3.

NO :

The procedure is complete.

AC302297

AC310120

AB

MB991827

16-pin

MB991910

MB991824

AC302297

AC310120

AB

MB991827

16-pin

MB991910

MB991824

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-49

STEP 3. Voltage 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) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 1 and

earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Go to Step 4.

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.

AC312620AG

Oil reservoir

Connector: A-03

ABS-ECU

MB991974

Check connector

A-03 Harness connector

A-03

Hydraulic unit
(with built-in ABS-ECU)

AC312621

Oil reservoir

Connector: A-03

AC

A-03

Hydraulic unit
(with built-in ABS-ECU)

A-03 Harness connector
(harness side)

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-50

STEP 5. Measure the resistance 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 result normal?

YES :

Go to Step 7.

NO :

Go to Step 6.

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

Q: Is the result normal?

YES :

An open circuit may be present in the earth

circuit. Repair the wiring harness between
ABS-ECU connector A-03 terminal 26 and
the body earth. Then go to Step 8.

NO :

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

AC312620AH

Oil reservoir

Connector: A-03

ABS-ECU

MB991974

Check connector

A-03 Harness connector

A-03

Hydraulic unit
(with built-in ABS-ECU)

AC312621

Oil reservoir

Connector: A-03

AC

A-03

Hydraulic unit
(with built-in ABS-ECU)

A-03 Harness connector
(harness side)