Mitsubishi Galant (2004+). Manual - part 528

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-57

STEP 6. Check ABS-ECU connector A-02 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.

Q: Is ABS-ECU connector A-02 damaged?

YES : Repair or replace the damaged component(s). Refer

to GROUP 00E, Harness Connector Inspection

P.00E-2

. Then go to Step 8.

NO : An open circuit may be present in the ground circuit.

Repair the wiring harness between ABS-ECU
connector A-02 terminal 18 and the body ground.
Then go to Step 8.

STEP 7. Recheck for diagnostic trouble code.

Check again if the DTC is set.
(1) Turn the ignition switch to the "ON" position.
(2) Erase the DTC.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
(4) Turn the ignition switch to the "ON" position.
(5) Check if the DTC is set.
(6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC C1266, C1273 or C1274 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.00-6

AC306406

22 21 20

A-02 HARNESS CONNECTOR
(HARNESS SIDE)

A-02 (GR)

CONNECTOR: A-02

HYDRAULIC UNIT
(WITH BUILT-IN ABS-ECU)

AC305412

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-58

STEP 8. Recheck for diagnostic trouble code.

Check again if the DTC is set.
(1) Turn the ignition switch to the "ON" position.
(2) Erase the DTC.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
(4) Turn the ignition switch to the "ON" position.
(5) Check if the DTC is set.
(6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC C1266, C1273 or C1274 set?

YES : Go to Step 1.
NO : The procedure is complete.

AC305412

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-59

DTC C1278/C1279 Valve Relay System

CAUTION

If there is any problem in the CAN bus lines, an
incorrect diagnostic trouble code may be set.
Prior to this diagnosis, diagnose the CAN bus
lines.

CIRCUIT 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
integrated in the ABS-ECU.

• The valve relay, which is integrated in the

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

ABS SOLENOID VALVE

HYDRAULIC UNIT

MOTOR

FUSIBLE
LINK

MOTOR
POWER
SUPPLY

SOLENOID
VALVE POWER
SUPPLY

ABS-ECU

AC308173

Solenoid Valve and Motor Power Supply Circuit

AC304742

A-02 (GR)

CONNECTOR: A-02

HYDRAULIC UNIT
(WITH BUILT-IN ABS-ECU)

AC305015AE

FUSIBLE LINK
No.3

RELAY BOX IN ENGINE COMPARTMENT

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-60

ABS DTC SET CONDITIONS
These diagnostic trouble codes will be set under the
cases below.

DTC C1278 (Valve relay OFF failure)

• After the ABS-ECU turned on the valve relay, the

solenoid valve is not energized (valve relay OFF
failure).

DTC C1278 (Valve relay ON failure)

• After the ABS-ECU turned off the valve relay, the

solenoid valve still remains energized (valve relay
ON failure).

TROUBLESHOOTING HINTS (The most likely
causes for these DTCs are to set are:)

Currect trouble

• Damaged wiring harness or connector

• Malfunction of the hydraulic unit (integrated with

ABS-ECU)

Past trouble
Carry out diagnosis with particular emphasis on con-
nector(s) or wiring harness between the power sup-
ply circuit (terminal 1) to the ABS-ECU solenoid
valve or ground circuit (terminal 2) . For diagnosis
procedures, refer to "How to cope with past trouble"
(Refer to GROUP 00, How to Use Troubleshoot-
ing/Inspection Service Points

P.00-6

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

• MB991970: ABS Check Harness

STEP 1. Using scan tool MB991958, diagnose the CAN bus
line.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link 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 CAN bus line found to be normal?

YES : Go to Step 3.
NO : Repair the CAN bus line (Refer to GROUP 54C,

Diagnosis

P.54C-14

). Then go to Step 2.

AC305412

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

Content .. 526 527 528 529 ..