Mitsubishi Galant 9G. Manual - part 1615

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-44

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 2 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

AF

ABS-ECU

MB991970

ABS CHECK
HARNESS

CHECK CONNECTOR

A-02 HARNESS CONNECTOR
(HARNESS SIDE)

A-02 (GR)

CONNECTOR: A-02

HYDRAULIC UNIT
(WITH BUILT-IN ABS-ECU)

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-45

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.00-14

.

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-46

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

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-47

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

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