Mitsubishi Montero (2002-2004). Manual - part 270

SYMPTOM PROCEDURES

TSB Revision

SWS SYMPTOM PROCEDURES

54Bb-127

INSPECTION PROCEDURE C-5: Central Door Locking System: All the doors do not lock with just the 
driver's inside lock knob operation.

.

TECHNICAL DESCRIPTION
The driver's door lock actuator switch or the ETACS-
ECU may be defective.

.

TROUBLESHOOTING HINTS

• The driver's door lock actuator switch may be 

defective

• The ETACS-ECU may be defective

• The wiring harness or connectors may have 

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

Central Door Lock (Door Lock Actuator Switch) Circuit

SYMPTOM PROCEDURES

TSB Revision

SWS SYMPTOM PROCEDURES

54Bb-128

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991502: Scan Tool (MUT-II) 

Check the input signal (by using the pulse check mode of 
the monitor.)
Check the input signals from the driver's door lock actuator 
switch.

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector 

(16-pin).

(2) Operate scan tool MB991502 as follows:

1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "PULSE CHECK."

(3) Lock or unlock the driver's inside lock knob.
(4) Check scan tool MB991502 sounds or not.
Q: Does scan tool MB991502 sound when the driver's 

inside lock knob is locked or unlocked, or the 
passenger's side lock knob is moved from the lock to 
the unlock position?
YES : Replace the ETACS-ECU. Verify that all the doors 

can be locked or unlocked by operating the driver's 
inside lock knob.

NO :  Refer to Inspection Procedure O-6 "ETACS-ECU 

does not receive a signal from the driver's door lock 
actuator switch 

P.54Bc-93

."

ACX01539

16-pin

MB991502

AI

SYMPTOM PROCEDURES

TSB Revision

SWS SYMPTOM PROCEDURES

54Bb-129

INSPECTION PROCEDURE C-6: Central Door Locking System: Forgotten key prevention function 
does not work normally.

NOTE: This troubleshooting procedure requires the 
use of scan tool MB991502 and SWS monitor kit 
MB991862. For details on how to use the SWS mon-
itor, refer to "How to use SWS monitor 

P.54Ba-8

."

.

CIRCUIT OPERATION
The ETACS-ECU operates the forgotten key preven-
tion function according to the following switches:

• Key reminder switch: OFF

• Driver's or front passenger's door switch: ON

• Driver's door lock actuator switch: being turned 

ON

The ETACS-ECU activates the forgotten key preven-
tion function under the following conditions:

• Ignition key: inserted into the ignition key cylinder

• Driver's or front passenger's door: open

• Driver’s or front passenger’s door lock: being 

locked electrically

• Driver’s door lock: being locked manually

.

TECHNICAL DESCRIPTION (COMMENT)
 If the forgotten key prevention function does not 
work normally, the input circuit from the switches or 
the ETACS-ECU may be defective.

.

TROUBLESHOOTING HINTS

• The key reminder switch may be defective

• The driver's or front passenger's door switch may 

be defective

• The driver's door lock actuator switch may be 

defective

• The ETACS-ECU may be defective

• The wiring harness or connectors may have 

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

Forgotten Key Prevention Circuit

SYMPTOM PROCEDURES

TSB Revision

SWS SYMPTOM PROCEDURES

54Bb-130

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991502: Scan Tool (MUT-II) 

• MB991862: SWS Monitor Kit

STEP 1. Use scan tool MB991502 to select "ECU COMM 
CHK" on the SWS monitor display.
Check the ETACS-ECU.

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502. 
(1) Connect scan tool MB991502 to the data link connector 

(16-pin).

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

connector (13-pin).

(3) Turn the ignition switch to the "LOCK" (OFF) position.
(4) Operate scan tool MB991502 as follows:

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

(5) Check scan tool MB991502 should show "OK" on the 

"ETACS ECU" menu.

Q: Is "OK" displayed on the "ETACS ECU" menu?

YES : Go to Step 2.
NO :  Refer to Inspection Procedure A-3 "Communication 

with ETACS-ECU is not possible 

P.54Bb-25

."

AC204222AB

16-pin

13-pin

MB991502

MB991862