Mitsubishi 380. Manual - part 27

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-105

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: OFF → ON

• Driver's seat belt: Unfastened

• All door: Closed

(1) Operate diagnostic 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: Turn the ignition switch from the OFF position to the 
ON position. Then item No.43 should be ON for approxi-
mately six seconds only.

Q: Does diagnostic 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. Verify that the seat belt 
tone alarm 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-408

."

Normal condition is not displayed for "BUZZER" : 

Replace the ETACS-ECU. Verify that the seat belt 
tone alarm function works normally.

ITEM NO.

ITEM NAME

NORMAL CONDITION

ITEM 30

IG SW (IG1)

ON

ITEM 43

BUZZER

ON (for approximately six 
seconds after the ignition 
switch is turned from OFF 
to ON), and then OFF

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC302210

COLUMN SWITCH 
CONNECTOR

COLUMN SWITCH 
CONNECTOR AT 
HARNESS SIDE 

MB991812

AB

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-106

INSPECTION PROCEDURE B-4: Tone Alarm: Door ajar Warning Buzzer Function does not Work 
Normally.

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

P.54B-13

."

.

CIRCUIT OPERATION

The ETACS-ECU controls the door-ajar warning tone 
alarm, based on the signals from the switches and 
sensors below.

• Ignition switch (IG1): ON

• One of the door switches: ON

• Vehicle speed signal: 8 km/h (5 mph) or more

.

TECHNICAL DESCRIPTION (COMMENT)

If the door-ajar warning tone alarm does not work, 
connector(s), wiring harness in the CAN bus lines, 
the combination meter, the ETACS-ECU or the input 
signal circuit may be defective.

.

TROUBLESHOOTING HINTS

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• 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 combination meter may be defective

• The ETACS-ECU may be defective

ETACS-

ECU

VEHICLES SPEED

SIGNAL

· 

ALL DOOR 

SWITCHES

· IGNITION SWITCH (IG1)

COMBINATION 

METER

CPU

CAN COMMUNICATION LINE

(CAN_L LINE)

CAN COMMUNICATION LINE

(CAN_H LINE)

Door Ajar Tone Alarm Function Circuit

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-107

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991958: diagnostic 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: Test Probe Harness

STEP 1. Check the adjustment function.

Q: Has the door-ajar warning tone alarm function been 

enabled by the adjustment function?
YES : Go to Step 2.
NO :  Enable the door-ajar warning tone alarm.

STEP 2. Using diagnostic tool MB991958, diagnose the 
CAN bus line.

CAUTION

To prevent damage to diagnostic tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting diagnostic tool 
MB991958.
(1) Connect diagnostic tool MB991958. Refer to "How to 

connect SWS monitor 

P.54B-13

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the CAN bus line found to be normal?

YES : Go to Step 3.
NO :  Repair the CAN bus line (Refer to GROUP 54C, 

Diagnosis 

P.54C-13

).

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-108

STEP 3. Using diagnostic tool MB991958, read the 
combination meter diagnostic trouble code. 
Check whether the combination meter-related DTC is set.
(1) Turn the ignition switch to the "ON" position.
(2) Check whether the combination meter-related DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES : Diagnose the combination meter (Refer to GROUP 

54A, Diagnostic trouble code chart 

P.54A-48

).

NO :  Go to Step 4.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827