Mitsubishi 380. Manual - part 958

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-57

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

Circuit drawings

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

Currect trouble

• Damaged wiring harness or connector

• Malfunction of the hydraulic unit (integrated with 

ABS-ECU)

.

Past trouble

Carry out diagnosis with particular emphasis on con-
nector(s) or wiring harness between the power sup-
ply circuit (terminal 3) to the ABS-ECU solenoid 
valve or ground circuit (terminal 1) . For diagnosis 
procedures, refer to "How to cope with past trouble" 
(Refer to GROUP 00, How to Use Troubleshoot-
ing/Inspection Service Points 

P.00-16

).

.

DIAGNOSIS

Required Special Tools:

• MB991958: Diagnostic Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

• MB991219: Inspection Test Harness

STEP 1. Using diagnostic tool MB991958, diagnose the 
CAN bus line.

CAUTION

To prevent damage to diagnostic tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting diagnostic tool 
MB991958.
(1) Connect diagnostic 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-15

).  Then go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-58

STEP 2. Recheck for diagnostic trouble code.

CAUTION

To prevent damage to diagnostic tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting diagnostic 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 C1278 or C1279 set?

YES : Go to Step 3.
NO :  The procedure is complete.

STEP 3. Measure the voltage at ABS-ECU connector A-02.
(1) Disconnect the connector A-02, and use special tool 

Inspection Check Harness (MB991219) to probe the wiring 
harness-side connector.

NOTE: The special tool (Inspection test harness) 
MB991219 for connector pin contact pressure should be 
used. The test probe should never be forcibly inserted, as it 
may cause a defective contact.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 3 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.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

35DB092A

CONNECTOR: A-02

HYDRAULIC UNIT

(WITH BUILT-IN ABS-ECU)

TEST 

HARNESS

(MB991219)

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-59

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 
3 and external (20 amp) fusible link. Then go to Step 
8.

16DB402A

A-02 (GR)

CONNECTOR: A-02 

A-02 HARNESS CONNECTOR:

FUSIBLE LINK
ABS (solenoid valve)  
       (20 A) 

RELAY BOX

35DB093A

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-60

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

Inspection Check Harness (MB991219) to probe the wiring 
harness-side connector.

NOTE: The special tool (Inspection test harness) 
MB991219 for connector pin contact pressure should be 
used. The test probe should never be forcibly inserted, as it 
may cause a defective contact.

(2) Measure the resistance between terminal 1 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.

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 1 and the body ground. Then 
go to Step 8.

35DB094A

CONNECTOR: A-02

HYDRAULIC UNIT

(WITH BUILT-IN ABS-ECU)

TEST 

HARNESS

(MB991219)

16DB402A

A-02 (GR)

CONNECTOR: A-02 

A-02 HARNESS CONNECTOR: