Mitsubishi Galant (2004+). Manual - part 236

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-135

STEP 4. Check the input signal by using "FUNCTION 
DIAG." menu of the SWS monitor.

Check the input signals from the following switches:

• Ignition switch: ON

• Driver’s door: Open

• All door: Closed

(1) Operate scan tool MB991958 according to the procedure 

below to display "OTHER ALARM"
a. Select "Interactive Diagnosis."
b. Select "System Select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "BUZZER."
g. Select "OTHER ALARM"

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

described in the table below.
NOTE: The scan tool MB991958 display changes when the 
driver's or the front passenger's door is opened. If any of the 
doors is open, the system cannot be checked correctly.

Q: Does scan tool MB991958 display the items "IG SW 

(IG1)" and "BUZZER" as normal condition?
Normal conditions are displayed for all the items : 

Replace the ETACS-ECU. Check that the turn-signal 
light buzzer function works normally.

Normal condition is not displayed for "IG SW (IG1)" : 

Refer to Inspection Procedure M-2 "ETACS-ECU 
does not receive any signal from the ignition switch 
(IG1) 

P.54B-490

."

Normal condition is not displayed for "BUZZER" : 

Replace the ETACS-ECU. Check that the turn-signal 
light buzzer function works normally.

ITEM NO.

ITEM NAME

NORMAL 
CONDITION

ITEM 30

IG SW (IG1)

ON

ITEM 43

BUZZER

ON

AC305411AB

MB991910

DATA LINK

CONNECTOR

MB991827

MB991824

MB991806

MB991812

AC302210

COLUMN SWITCH 
CONNECTOR

COLUMN SWITCH 
CONNECTOR AT 
HARNESS SIDE 

MB991812

AB

CONTINUE

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-136

54B

CENTRAL DOOR LOCKING SYSTEM

GENERAL DESCRIPTION CONCERNING CENTRAL DOOR LOCKING SYSTEM

M1549021100152

The following ECUs affect the functions and control 
of the central door locking system.

Central door locking system

.

Door unlocking by operating the driver’s door lock key 
cylinder
When the ignition key is inserted in the driver’s door lock key 
cylinder and turned clockwise to unlock the driver’s door, the 
ETACS-ECU operates its door unlock relay and passes a cur-
rent through the door lock actuator of the driver’s door for 0.25 
seconds to unlock only the driver’s door.
When the ignition key is turned clockwise again, the 
ETACS-ECU operates its door unlock relay and passes a cur-
rent through the door lock actuators of all doors for 0.25 sec-
onds and to unlock all doors.
NOTE: Vehicles with a multi center display (middle grade type) 
can be customized so that a single unlock operation will unlock 
all doors. Refer to 

P.54B-578

.

.

FUNCTION

CONTROL ECU

Central door locking system

ETACS-ECU

Forgotten key prevention function

ETACS-ECU

AC305383 AB

ON 

(UNLOCK)

OFF

DRIVER'S
DOOR LOCK KEY 
CYLINDER SWITCH

t: 0.25 SECOND

OFF

ON

DRIVER'S DOOR 
UNLOCK RELAY 
OUTPUT

LOCK

UNLOCK

LOCK

UNLOCK

DRIVER'S DOOR 
LOCK ACTUATOR 

t

ALL DOOR'S
LOCK ACTUATOR

t

OFF

ON

t

OTHER DOOR 
UNLOCK RELAY 
OUTPUT

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-137

Door locking or unlocking by operating the driver’s or 
front passenger’s door lock switch
When the door is locked by the driver’s or front passenger’s 
door lock switch, the ETACS-ECU operates its door lock relay 
and passes a current through the door lock actuators of all 
doors for 0.25 seconds to lock all doors.
When the door is unlocked by the driver’s or front passenger's 
door lock switch, the ETACS-ECU operates its door unlock 
relay and passes a current through the door lock actuators of 
all doors for 0.25 seconds to unlock all doors.
When the door is locked and unlocked by driver’s or front pas-
senger's door lock switch consecutively, the ETACS-ECU oper-
ates its door lock relay and passes a current through the door 
lock actuators of all doors for 0.25 seconds to lock all doors. 
Then, the ETACS-ECU operates its door unlock relay and 
passes a current through the door lock actuators of all doors for 
0.25 seconds to unlock all doors. Due to this, there may be a 
time lag between the driver’s or front passenger's door lock 
switch actuation and the time when all doors are unlocked.

AC305384

t

AB

ON

(LOCK)

ON

(UNLOCK)

ON

OFF

ON

OFF

DRIVER'S OR 
FRONT 
PASSENGER'S 
DOOR LOCK 
SWITCH

UNLOCK RELAY 
OUTPUT

LOCK RELAY 
OUTPUT

t: 0.25 SECOND

t

t

TIME LAG

t

t

OFF

LOCK

UNLOCK

ALL DOORS
LOCK 
ACTUATOR

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-138

Forgotten key prevention function

If the driver's door is locked while it is open

If the driver's door is locked while it is open and when 
the key is still in the ignition key cylinder, approxi-
mately 0.3 second later the ETACS-ECU activates 
the unlock relay output for 0.25 second to prevent 
the door from being locked with the key inside the 
vehicle.

In addition, if locking the door was not prevented, a 
re-try current is sent (an unlock relay output ON is 
sent for 0.25 second up to 5 times including the first 
attempt).
NOTE: The dotted line indicates that the system is 
trying to turn on the unlock relay if the door cannot be 
unlocked.

AC209078AB

ON

OFF

ON

OFF

Lock relay output

Unlock relay output

LOCK

UNLOCK

Driver's door 
lock actuator 

ON (Key removed)

OFF (Key inserted)

Key reminder switch

t

ON (Driver's door  is open)

Driver's door switch

OFF (Driver's door is closed)

t

t: 0.3 seconds
T1: 0.25 seconds
T2: 1 seconds

T2

T2

T2

T2

T1

T1

T1

T1

T1

T1