Mitsubishi Galant. Manual — part 525

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-33

CIRCUIT OPERATION

•

The ABS-ECU controls the continuity to the ABS
warning light by turning the power transistor in
the unit "ON" and "OFF" to turn the ABS warning
relay "ON" and "OFF".

TECHNICAL DESCRIPTION (COMMENT)
The cause is probably an ABS warning light relay
hydraulic unit (integrated with ABS-ECU)
malfunction.

TROUBLESHOOTING HINTS
The mostlikely causes for this case:

•

Damaged wiring harness

•

Malfunction of the hydraulic unit (integrated with
ABS-ECU)

•

Malfunction of the ABS warning light relay

DIAGNOSIS

Required Special Tool:

•

MB991223: Harness Set

AC003695 AB

CONNECTOR: A-03

AC003856AB

CONNECTOR: C-05

COMBINATION
METER

AC003870 AB

CONNECTOR: C-66

CONNECTOR
BLOCK (LH)

AC003923 AB

CONNECTOR: A-10X

RELAY BOX IN

ENGINE

COMPARTMENT

AC003919

CONNECTOR: C-30

AB

AC003082AK

CONNECTORS: C-73, C-77

C-73

JUNCTION BLOCK
(FRONT VIEW)

C-77

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-34

STEP 1. Check the ABS warning light relay continuity.
(1) Remove the ABS warning light relay.
(2) Check the continuity between terminal number 1 and

number 3 and between terminal number 5 and number 2 at
the ABS warning light relay.

Q: Is the ABS warning light relay continuity?

YES : Go to Step 2.
NO : Replace the ABS warning light and then go to Step 7.

STEP 2. Check the ABS warning light relay continuity.
(1) Remove the ABS warning light relay.
(2) Apply the positive terminal of the battery to the No. 1

terminal and the negative terminal to the No. 3 terminal, and
then check the continuity between the No. 5 terminal and
the No. 2 terminal.

Q: Is the ABS warning light relay continuity?

YES : Replace the ABS warning light and then go to Step 7.
NO : Go to Step 3.

STEP 3. Check the power supply circuit at the ABS
warning light relay connector A-10X.
(1) Start the engine.
(2) Measure at the relay box in engine compartment side the

voltage between the terminal 1 and ground.

Q: Is the voltage approximately 12 volts?

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

AC003921

AC003920

A-10X (RELAY BOX IN ENGINE
COMPARTMENT)

AB

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-35

STEP 4. Check the harness wire between ignition switch
(IG2) and ABS warning light relay connector A-10X.
NOTE: After inspecting intermediate connector C-66, C-73 or
C-77 inspect the wire. If intermediate connector C-66, C-73 or
C-77 is damaged, repair or replace it. Refer to GROUP 00E,
Harness Connector Inspection

P.00E-2

. If the connector has

been repaired or replaced, go to Step 7.

Q: Are any harness wire between the ignition switch (IG1)

and ABS warning light relay connector A-10X damage?
YES : Go to Step 5.
NO : Repair the harness wire and then go to Step 7.

AC003923 AB

CONNECTOR: A-10X

RELAY BOX IN

ENGINE

COMPARTMENT

AC003870 AB

CONNECTOR: C-66

CONNECTOR
BLOCK (LH)

AC003082AK

CONNECTORS: C-73, C-77

C-73

JUNCTION BLOCK
(FRONT VIEW)

C-77

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-36

STEP 5. Check the harness wire between ABS-ECU
connector A-03 and ABS warning light relay connector A-
10X.
NOTE: After inspecting intermediate connector C-05, inspect
the wire. If intermediate connector C-05, is damaged, repair or
replace it. Refer to GROUP 00E, Harness Connector
Inspection

P.00E-2

. If the connector has been repaired or

replaced, go to Step 7.

Q: Are any harness wire between the ABS-ECU connector

A-03 and ABS warning light relay connector A-10X
damage?
YES : Repair the harness wire and then go to Step 7.
NO : Go to Step 6.

AC003695 AB

CONNECTOR: A-03

AC003923 AB

CONNECTOR: A-10X

RELAY BOX IN

ENGINE

COMPARTMENT

AC003856AB

CONNECTOR: C-05

COMBINATION
METER