Mitsubishi 380. Manual - part 69

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-273

INSPECTION PROCEDURE H-5: Headlamp and Taillamp: Headlamps do not illuminate when the 
lighting switch is at "TAIL," and "PASSING" position, but illuminate at low-beam when the switch is at 
"HEAD" position. At this position, the headlamps cannot be changed to high beam by operating the 
dimmer switch.

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

."

.

TECHNICAL DESCRIPTION (COMMENT)

If the headlamps illuminate at low-beam regardless 
of the lighting switch positions, the headlamp opera-
tion is in fail-safe mode.

.

TROUBLESHOOTING HINTS

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• The wiring harness or connectors may have 

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

• The front-ECU may be defective

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

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-274

Use Diagnostic Tool MB991958 to select "ECU COMM 
Check" on the SWS monitor display. 
Check the following ECUs:

• ETACS-ECU

• Column-ECU

• Front-ECU

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. Connect special tool MB991910 before con-
necting 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 Diagnostic Tool MB991958 according to the 

procedure below to display "ECU COMM Check."
a. Select "System select."
b. Select "SWS."
c. Select "SWS MONITOR."
d. Select "ECU COMM Check."

(4) Diagnostic Tool MB991958 should show "OK" on the "ECU 

COMM Check" menus for the "ETACS ECU", "COLUMN 
ECU" and "FRONT ECU" menus.

Q: Is "OK" displayed for both the "ETACS ECU", "COLUMN 

ECU" and "FRONT ECU" menus?
"OK" is displayed for all the items : Replace the 

front-ECU. Verify that the headlamps and the 
taillamps illuminate normally.

"NG" is displayed for the "ETACS ECU" menu : Refer to 

Inspection Procedure A-3 "Communication with the 
ETACS-ECU is not possible 

P.54B-74

."

"NG" is displayed for the "COLUMN ECU" menu : Refer 

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

P.54B-68

."

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

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

P.54B-80

."

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-275

INSPECTION PROCEDURE H-6: Headlamp and Taillamp: The front park lamps, taillamps or the 
licence plate lamps do not illuminate.

.

TECHNICAL DESCRIPTION (COMMENT)

If  the front park lamps,  taillamps or the licence plate 
lamp do not illuminate, their bulb may be defective.

.

TROUBLESHOOTING HINTS

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• The front park lamp bulb may be defective

• The stop/taillamp bulb may be defective

• The licence plate lamp bulb may be defective

• The wiring harness or connectors may have 

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

.

AC305977AE

CONNECTOR: A-11X

16DB433A

A-32

CONNECTORS:   A-32

16DB434A

A-20

CONNECTOR: A-20

AC305260

CONNECTORS: F-06, F-06, F-09

AD

F-03

F-06

F-09

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-276

DIAGNOSIS

Required Special Tool:

• MB991223: Harness Set

STEP 1. Check the operation of each lamp.

Q: Which lamp does not illuminate?

front park lamp (LH), taillamp (LH), and licence plate 
lamp : Go to Step 2.
front park lamp (RH), taillamp (RH) : Go to Step 4.
taillamp (LH) and licence plate lamp : Go to Step 6.
taillamp (LH) : Go to Step 8.
taillamp (RH) : Go to Step 13.
front park lamp (LH) : Go to Step 19.
front park lamp (RH) : Go to Step 25.
licence plate lamp : Go to Step 31.
All lamps : Refer to Inspection Procedure H-1 "The 

taillamps do not illuminate normally 

P.54B-260

."

STEP 2. Check front-ECU connector A-11X for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is front-ECU connector A-11X in good condition?

YES : Go to Step 3.
NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

. The front park lamp (LH), taillamp (LH),  and 

the licence plate lamp should illuminate normally.

AC305977AH

CONNECTOR: A-11X

RELAY BOX SIDE