Mitsubishi Galant 9G. Manual - part 1617

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-52

STEP 5. Measure the resistance at ABS-ECU connector 
A-02.
(1) Disconnect the connector A-02, and connect special tool 

ABS Check Harness (MB991970) to the wiring 
harness-side connector.
NOTE: Do not connect special tool ABS Check Harness 
(MB991970) to the ABS-ECU.

(2) Measure the resistance between terminal 18 and ground. It 

should be 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 7.
NO :  Go to Step 6.

AC306403

19

2

18

1

8

9

7

6

5

4

3

10

11   

25

15

16

17

27

28

26

12

13

14

23

24

22 21 20

A-02(GR)

CONNECTOR: A-02

HYDRAULIC UNIT
(WITH BUILT-IN ABS-ECU)

AH

ABS-ECU

MB991970

CHECK CONNECTOR

A-02 HARNESS
CONNECTOR

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-53

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.00-14

.

AC306406

19

2

18

1

8

9

7

6

5

4

3

10

11   

25

15

16

17

27

28

26

12

13

14

23

24

22 21 20

A-02 HARNESS CONNECTOR
(HARNESS SIDE)

AB

A-02 (GR)

CONNECTOR: A-02

HYDRAULIC UNIT
(WITH BUILT-IN ABS-ECU)

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-54

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

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-55

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 DTC SET CONDITIONS

These diagnostic trouble codes will be set under the 
cases below.

ABS SOLENOID VALVE

HYDRAULIC UNIT

MOTOR

FUSIBLE 
LINK

MOTOR 
POWER 
SUPPLY

SOLENOID 
VALVE POWER 
SUPPLY

ABS-ECU

3

AC308173

AB

Solenoid Valve and Motor Power Supply Circuit

AC304742

A-02 (GR)

CONNECTOR: A-02

HYDRAULIC UNIT
(WITH BUILT-IN ABS-ECU)

AC

AC305015AE

FUSIBLE LINK
No.3

RELAY BOX IN ENGINE COMPARTMENT