Mitsubishi Galant. Manual — part 520

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-13

DTC 38 : Stoplight Switch System

AC003901AB

Stoplight Switch Circuit

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-14

CIRCUIT OPERATION

•

The ON signal when the brake pedal is pressed
or the OFF signal when the brake pedal is
released is input to the ABS-ECU (terminal 18).

ABS DTC SET CONDITION
Output is provided in the following cases:

•

Stoplight switch is not operating properly and
remains in ON state for more than 15 minutes.

•

Stoplight switch system harness is damaged and
no signal is input to ABS-ECU.

TROUBLESHOOTING HINTS
The most likely causes for DTC is to set are:

•

Malfunction of the stoplight switch

•

Damaged wiring harness and connector

•

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

AC003695 AB

CONNECTOR: A-03

AC003858

GLOVE BOX

AB

CONNECTOR: C-13

AC003868 AB

CONNECTOR: C-85

JUNCTION BLOCK (REAR VIEW)

AC003869

JUNCTION BLOCK (RH)

CONNECTOR: C-71

AB

AC003902

CONNECTORS: C-03, C-57

AB

C-57

C-03

AC003871

JUNCTION BLOCK (FRONT VIEW)

CONNECTOR: C-77

AB

AC003870 AB

CONNECTOR: C-66

CONNECTOR
BLOCK (LH)

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-15

DIAGNOSIS

Required Special Tool:

•

MB991223: Harness Set

STEP 1. Check the stoplight operation.

Q: Does the stoplight light or go out correctly?

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

STEP 2. Check the stoplight switch installation condition.

Q: Is the stoplight switch installed properly?

YES : Go to Step 4.
NO : Repair it and then go to Step 7.

STEP 3. Check the stoplight switch circuit at ABS-ECU
connector A-03.
(1) Disconnect connector A-03 and measure at the harness

side.

(2) Turn the stoplight switch "ON".
(3) Measure the voltage between terminal 18 and ground.

Q: Is the battery positive voltage approximately 12 volts?

YES : Replace the hydraulic unit and then go to Step 7.
NO : Go to Step 5.

STEP 4. Check the stoplight switch continuity.
(1) Remove the stoplight switch. (Refer to GROUP 35A, Brake

Pedal

P.35A-30

.)

(2) Connect an ohmmeter to the stoplight switch terminals 1

and 2, and check whether there is continuity when the
plunger of the stoplight switch is pushed in and when it is
released.

(3) The stoplight switch is in good condition if there is no

continuity when the plunger is pushed in to a depth of within
4 mm (0.2 inch) from the outer case edge surface, and if
there is continuity when it is released.

Q: Is the stoplight switch damaged?

YES : Replace it and then go to Step 7.
NO : Go to Step 6.

AC003905

A-03 (HARNESS SIDE)

AB

AC002295 AB

AC000943 AB

NO CONTINUITY
(OFF)

CONTINUITY
(ON)

4 mm (0.2 in)

ANTI-SKID BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM(ABS)

35B-16

STEP 5. Check the harness wire between ABS-ECU
connector A-03 and stoplight switch connector C-66.
NOTE: After inspecting intermediate connector C-13, C-57 or
C-71 inspect the wire. If intermediate connector C-13, C-71 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.

AC003858

GLOVE BOX

AB

CONNECTOR: C-13

AC003869

JUNCTION BLOCK (RH)

CONNECTOR: C-71

AB

AC003089AE

CONNECTOR: C-57