Mitsubishi Galant (2004+). Manual - part 526

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-49

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 2 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 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.00-6

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-50

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 C1226, C1231, C1236, C1241, C1246, C1251,

C1256 or C1261 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-51

DTC C1266/C1273/C1274: Motor 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 19) for the pump motor. The pump
motor is energized by the motor relay, which is
integrated in the ABS-ECU.

• The motor relay, which is integrated in the

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

• The ABS-ECU activates the pump motor by turn-

ing on the ECU built-in motor relay when the ABS
is working.

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-52

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

DTC C1266: Motor system (seizure)

• This DTC is set when the ECU determines the

pump motor is not running smoothly (i.e. motor
seizure) by the motor relay ON/OFF.

DTC C1273: Motor relay problem (stuck off)

• If the ABS-ECU determines that the motor is not

running after the motor relay is turned on, the
ECU determines that the motor relay is stuck off,
and sets this DTC.

DTC C1274: Motor relay problem (stuck on)

• If the ABS-ECU determines that the motor is run-

ning after the motor relay is turned off, the ECU
determines that the motor relay is stuck on, and
sets this DTC.

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

Current trouble

• Damaged wiring harness or connector

• Malfunction of the hydraulic unit (integrated with

ABS-ECU)

Past trouble

• Carry out diagnosis with particular emphasis on

connector(s) or wiring harness between the
power supply circuit (terminal 19) to the
ABS-ECU motor or ground circuit (terminal 18).
For diagnosis procedures, refer to "How to cope
with past trouble" (Refer to GROUP 00, How to
Use Troubleshooting/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

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