Mitsubishi Montero (2004+). Manual - part 750

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-257

.

CIRCUIT OPERATION
The windshield washer switch sends a signal 
through the column-ECU (incorporated in the column 
switch) to the front-ECU. If the column-ECU sends a 
windshield washer switch "ON" signal to the 
front-ECU, the front-ECU turns on the relay (incorpo-
rated in the front-ECU), thus causing the windshield 
washer motor to be turned on.

.

TECHNICAL DESCRIPTION (COMMENT)
If the windshield washer does not work normally, the 
windshield washer motor, the column switch (wind-
shield wiper and washer switch) or the front-ECU 
may be defective.

.

TROUBLESHOOTING HINTS

• The windshield washer motor may be defective

• The column switch (windshield wiper and washer 

switch) may be defective

• The front-ECU may be defective

• The wiring harness or connectors may have 

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

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

• MB991911: MUT-III Main Harness B

• MB991813: SWS Monitor Kit

• MB991806: SWS Monitor Cartridge

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

• MB991822: Probe Harness

STEP 1. Verify the windshield wiper.
Q: Does the windshield wiper operate normally?

YES : Go to Step 2.
NO :  Refer to Inspection Procedure G-1 "Windshield wiper 

does not work at all 

P.54B-231

."

AC205138

CONNECTOR: A-08X

AB

BATTERY

FRONT-ECU

A-08X

AC205145AB

CONNECTOR: A-33

A-33

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-258

STEP 2. Use scan tool MB991958 to select "ECU COMM 
CHK" 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 
the DLC harness before connecting the column-ECU har-
ness. Be sure to connect SWS monitor kit MB991862 after 
turning on scan tool MB991958. 
(1) Connect the special tool. Refer to "How to connect SWS 

monitor 

P.54B-7

(2) Connect SWS monitor kit MB991862 to the data link 

connector (13-pin).

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

below to display "ECU COMM CHECK."

1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. Select "ECU COMM CHK".

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

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

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

ECU" menu?
"OK" is displayed for all the items : Go to Step 3.
"NG" is displayed on the "COLUMN ECU" menu : Refer 

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

P.54B-35

."

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

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

P.54B-48

."

AC309091

MB991911

MB991827

MB991824 

AB

MB991806

MB991862

DATA LINK
CONNECTOR 
(16-PIN)

DATA LINK
CONNECTOR 
(13-PIN)

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-259

STEP 3. Check the input signal by using "FUNCTION 
DIAG." menu of the SWS monitor.
Check the input signals from the following switches:

• Ignition switch: ON

• Windshield washer switch: ON

Operate scan tool MB991958 according to the procedure below 
to display "F.WIPER WASH."

1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. Select "FUNCTION DIAG."
5. Select "WIPER."
6. Select "F.WIPER WASH."

Check that normal conditions are displayed on the items 
described in the table below.

Q: Are normal conditions displayed for "FRONT 

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

Step 4.

The scan tool does not show the respective normal 
condition for item "FRONT WASH. SW" : Replace the 

column switch. Verify that the windshield washer 
works normally.

The scan tool does not show the respective normal 
condition for item "FRONT ECU ACK" : Replace the 

front-ECU. Verify that the windshield washer works 
normally.

STEP 4. Check windshield washer motor connector A-33 
for loose, corroded or damaged terminals, or terminals 
pushed back in the connector.
Q: Is windshield washer motor connector A-33 in good 

condition?
YES : Go to Step 5.
NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

. Verify that the windshield washer works 

normally.

ITEM NO.

ITEM NAME

NORMAL 
CONDITION

ITEM 09

FRONT 
WASH.SW

ON

ITEM 70

FRONT ECU ACK NORMAL ACK or 

HI-BEAM ACK

AC309091

MB991911

MB991827

MB991824 

AB

MB991806

MB991862

DATA LINK
CONNECTOR 
(16-PIN)

DATA LINK
CONNECTOR 
(13-PIN)

AC205145AE

CONNECTOR: A-33

HARNESS SIDE

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-260

STEP 5. Check the windshield washer motor.
(1) Disconnect windshield washer motor connector A-33, and 

check at windshield washer motor connector side.

(2) Fill the windshield washer tank with washer fluid.

(3) Connect windshield washer motor connector terminal 1 to 

the positive battery terminal, and terminal 2 to the negative 
battery terminal, respectively. Washer fluid should spray 
out.

Q: Does the windshield washer motor operate normally?

YES : Go to Step 6.
NO :  Replace the windshield washer motor. Verify that the 

windshield washer works normally.

STEP 6. Check the ground circuit to the windshield washer 
motor. Test at connector A-33. 
(1) Disconnect windshield washer motor connector A-33 and 

measure the resistance available at the wiring harness side 
of the connector. 

(2) Measure the resistance value between terminal 2 and 

ground.

• The resistance should equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 8.
NO :  Go to Step 7.

AC205145AE

CONNECTOR: A-33

HARNESS SIDE

AC309228AB

AC205145AE

CONNECTOR: A-33

HARNESS SIDE

AC209364KQ

CONNECTOR A-33
(HARNESS SIDE)