Mitsubishi Galant (2004+). Manual - part 536

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-89

INSPECTION PROCEDURE 2: Power Supply Circuit System

.

CIRCUIT OPERATION

• The ABS-ECU is energized by the ignition switch 

(IG1) through multi-purpose fuse 23 and the 
ABS-ECU terminal 20.

• If the power supply to the ABS-ECU has failed, 

scan tool (MUT-III Sub Assembly) will not be able 
to communicate with it.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this case:) 

• Damaged wiring harness or connector

• Defective battery

• Charging system failed

• Malfunction of the hydraulic unit (integrated with 

ABS-ECU)

.

JUNCTION 
BLOCK

IGNITION 
SWITCH (IG1)

POWER 
SUPPLY

ABS-ECU

ABS-ECU Power Supply and Ground Circuit

AC304742

A-02 (GR)

CONNECTOR: A-02

HYDRAULIC UNIT
(WITH BUILT-IN ABS-ECU)

AC

AC305415

CONNECTORS : C-214, C-215

C-214

C-215

AW

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-90

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. Measure the voltage 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) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 20 and ground. It 

should measure approximately 12 volts (battery positive 
voltage).

Q: Is battery positive voltage (approximately 12 volts) 

present?
YES : Go to Step 3.
NO :  Go to Step 2.

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)

AI

ABS-ECU

MB991970

CHECK CONNECTOR

A-02 HARNESS
CONNECTOR

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-91

STEP 2. Check ABS-ECU connector A-02, junction block 
connectors C-214, C-215 and ignition switch connector 
C-308 for loose, corroded or damaged terminals, or 
terminals pushed back in the connector.

• ABS-ECU connector A-02

• Junction block connectors C-214 and C-215

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)

AC305416AJ

C-214

CONNECTORS: C-214, C-215

C-215

1

3 4

2

6

5

C-214

6

1

7

2

9

8

10

3

5

12

11

4

1314

C-215

JUNCTION BLOCK
(FRONT VIEW)

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-92

• Ignition switch connector C-308

Q: Are the connectors and terminals in good condition?

YES : An open or short circuit may be present in the power 

supply line to the ABS-ECU. Repair the wiring 
harness between ABS-ECU connector A-02 terminal 
20 and ignition switch connector C-308 terminal 4. 
Then go to Step 8.

NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

. Then go to Step 8.

STEP 3. 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, 18 and ground. 

It should be 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 5.
NO :  Go to Step 4.

AC305235AG

CONNECTOR: C-308

C-308

2
5

4

1

6

3

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