Mitsubishi Galant (2004+). Manual - part 245

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-171

INSPECTION PROCEDURE C-6: Central Door Locking System: Forgotten Key Prevention Function 
does not Work Normally.

NOTE: This troubleshooting procedure requires use 
of scan tool MB991958 and SWS monitor kit 
MB991813. For details on how to use the SWS mon-
itor, refer to "How to use SWS monitor 

P.54B-15

."

.

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

• Key reminder switch: OFF

• Front door switch: ON

• Front door lock actuator switch: being turned on

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

• Ignition key: inserted into the ignition key cylinder

• Front door: open

• Front door lock: being locked

.

TECHNICAL DESCRIPTION (COMMENT)
If the function does not work normally, the input cir-
cuit system from the switches or the ETACS-ECU 
may be defective (refer to "CIRCUIT OPERATION").

.

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 ETACS-ECU may be defective

DOOR LOCK ACTUATOR

INPUT SIGNAL

·DRIVER'S DOOR LOCK ACTUATOR SWITCH

FUSIBLE 
LINK

1

JUNCTION BLOCK SIDE

JUNCTION 
BLOCK

ETACS-ECU

·FRONT DOOR SWITCH
·FRONT PASSENGER'S DOOR LOCK
 ACTUATOR SWITCH
·KEY REMINDER SWITCH

UNLOCK
RELAY

LOCK 
RELAY

(                 )

(             )

Forgotten Key Prevention Circuit

SYMPTOM PROCEDURES

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SIMPLIFIED WIRING SYSTEM (SWS)

54B-172

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

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-173

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

Check the ETACS-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 "LOCK" (OFF) 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" menu for the "ETACS ECU" menu.

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

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

with the ETACS-ECU is not possible 

P.54B-79

."

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC302210

COLUMN SWITCH 
CONNECTOR

COLUMN SWITCH 
CONNECTOR AT 
HARNESS SIDE 

MB991812

AB

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-174

STEP 2. Check the input signal by using "DATA LIST" 
menu of the SWS monitor.

Turn the ignition switch to the "ON" position before checking 
input signals from the ignition switch (IG1).
(1) Operate the scan tool MB991958 according to the 

procedure below to display "ETACS ECU."
a. Select "Interactive Diagnosis."
b. Select "System Select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Data List."
f. Select "ETACS ECU."

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

described in the table below.

Q: Does scan tool MB991958 display "FRONT DOOR SW" 

as normal condition?
YES : Go to Step 3.
NO :  Refer to Inspection Procedure M-4 "ETACS-ECU 

does not receive any signal from the front door 
switches 

P.54B-497

."

ITEM NO.

ITEM NAME

NORMAL CONDITION

ITEM 32

FRONT DOOR SW ON

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC302210

COLUMN SWITCH 
CONNECTOR

COLUMN SWITCH 
CONNECTOR AT 
HARNESS SIDE 

MB991812

AB