Mitsubishi Galant 9G. Manual — part 1616

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-48

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.00-16

).

.

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

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-49

STEP 2. Recheck for diagnostic trouble code.

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) 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 3.
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-50

STEP 3. 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 19 and ground. It

should be approximately 12 volts (battery positive voltage).

Q: Is the voltage approximately 12 volts (battery positive

voltage)?
YES : Go to Step 5.
NO : Go to Step 4.

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)

AG

ABS-ECU

MB991970

CHECK CONNECTOR

A-02 HARNESS
CONNECTOR

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-51

STEP 4. 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 or short circuit may be present in the

solenoid valve power supply circuit. Repair the wiring
harness between ABS-ECU connector A-02 terminal
19 and fusible link No.3.Then go to Step 8.

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)