Mitsubishi Galant 9G. Manual — part 66

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-260

.

CIRCUIT OPERATION

• The windshield wiper and washer switch sends a

signal through the column-ECU (incorporated in
the column switch) to the front-ECU. If the col-
umn-ECU sends a windshield wiper and washer
switch "ON" signal to the front-ECU, the
front-ECU turns on the relay (incorporated in the
front-ECU), thus causing the windshield wiper
and washer motor to be turned on.

• If the SWS communication line is defective, the

front-ECU operates windshield wiper motor by
using the other communication lines (wiper
backup circuit) instead of that line. In this case,
the windshield wiper works at low speed regard-
less of the windshield wiper and washer switch
positions ("LO" or "HIGH").

.

TECHNICAL DESCRIPTION (COMMENT)

If the windshield wiper does not work at all, the wind-
shield wiper motor, column switch (windshield wiper
and washer switch) or the front-ECU may be defec-
tive.

.

TROUBLESHOOTING HINTS

• Trouble in input signal system

• The wiring harness or connectors may have

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector

• The wiper motor may be defective

• The column switch may be defective

• The front-ECU may be defective

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• 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

• MB991813: SWS Monitor Kit

• MB991806: SWS Monitor Cartridge

• MB991812: SWS Monitor Harness (For Column-ECU)

• MB991822: Probe Harness

AC305206

A-03 (B)

CONNECTOR: A-03

AI

AC305977

CONNECTOR: A-12X

AF

AC305231

CONNECTOR: C-29

AH

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-261

STEP 1. Use scan tool MB991958 to select "ECU COMM
Check" on the SWS monitor display.
Check the following ECUs:

• Column-ECU

• Front-ECU

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. Connect
special tool MB991910 before connecting special tool
MB991812. Be sure to connect special tool MB991806 after
turning on special tool MB991824.
(1) Connect the special tool. Refer to "How to connect SWS

monitor

P.54B-13

."

(2) Turn the ignition switch to the "ON" position.
(3) Operate scan tool MB991958 according to the procedure

below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."

(4) Scan tool MB991958 should show "OK" on the "ECU

COMM Check" menus for both the "COLUMN ECU" and
the "FRONT ECU" menus.

Q: Is "OK" displayed for the "COLUMN ECU" and "FRONT

ECU" menu?
"OK" is displayed for all the items : Go to Step 2.
"NG" is displayed for the "COLUMN ECU" menu : Refer

to Inspection Procedure A-2 "Communication with the
column switch (column-ECU) is not possible

P.54B-71

."

"NG" is displayed for the "FRONT ECU" menu : Refer to

Inspection procedure A-4 "Communication with the
front-ECU is not possible

P.54B-86

."

AC305411AB

MB991910

DATA LINK

CONNECTOR

MB991827

MB991824

MB991806

MB991812

AC302210

COLUMN SWITCH
CONNECTOR

COLUMN SWITCH
CONNECTOR AT
HARNESS SIDE

MB991812

AB

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-262

STEP 2. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
Check the input signals from the following switches:

• Ignition switch: ACC

• Windshield wiper switch: INT

(1) Operate the MUT-III according to the procedure below to

display "F.WIPER INT."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "WIPER."
g. Select "F.WIPER INT."

(2) Check that normal conditions are displayed for the items

described in the table below.

Q: Are normal conditions displayed for "INT WIPER SW"

and "FRONT ECU ACK"?
Normal conditions displayed for all the items : Go to

Step 3.

Normal condition is not displayed for the "INT WIPER
SW" : Replace the column switch. Verify that the windshield

wiper works normally.

Normal condition is not displayed for the "FRONT ECU
ACK" : Replace the front-ECU. Verify that the windshield

wiper works normally.

STEP 3. Check windshield wiper motor connector A-03 for
loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is windshield wiper motor connector A-03 in good

condition?
YES : Go to Step 4.
NO : Repair or replace the damaged component(s). Refer

to GROUP 00E, Harness Connector Inspection

P.00E-2

. Verify that the windshield wiper works

normally.

ITEM NO.

ITEM NAME

NORMAL
CONDITION

ITEM 05

INT WIPER SW

ON

ITEM 70

FRONT ECU ACK NORMAL ACK or

HI-BEAM ACK

AC305411AB

MB991910

DATA LINK

CONNECTOR

MB991827

MB991824

MB991806

MB991812

AC302210

COLUMN SWITCH
CONNECTOR

COLUMN SWITCH
CONNECTOR AT
HARNESS SIDE

MB991812

AB

AC305206

A-03 (B)

HARNESS SIDE

CONNECTOR: A-03

AH

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-263

STEP 4. Check the windshield wiper motor.
(1) Disconnect windshield wiper motor connector A-03.

(2) Connect a battery to the windshield wiper motor as shown.

Then check that the windshield wiper motor operates
normally at high and low speeds.

Q: Does the windshield wiper motor operate normally?

YES : Go to Step 5.
NO : Replace the windshield wiper motor. Verify that the

windshield wiper works normally.

AC305206

A-03 (B)

HARNESS SIDE

CONNECTOR: A-03

AH

AC306750

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

CHECK OPERATION

LOW SPEED

HIGH SPEED

AB