Mitsubishi 380. Manual - part 85

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-337

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 a 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 

P.54A-48

.

NO :  Go to Step 4.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-338

STEP 4. Use Diagnostic Tool MB991958 to select "ECU 
COMM Check" on the SWS monitor display. 
Check the ETACS-ECU.

CAUTION

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 SWS monitor. Refer to "How to connect SWS 

monitor 

P.54B-13

."

(2) Turn the ignition switch to the "ON" position.
(3) Operate Diagnostic 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) Diagnostic 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 5.
NO :  Refer to Inspection Procedure A-3 "Communication 

with the ETACS-ECU is not possible 

P.54B-74

."

STEP 5. Replace the combination meter.
(1) Replace the combination meter.
(2) Check that the turn-signal lamp indicator lamps illuminate 

normally.

Q: Are the turn-signal indicator lamps in good condition?

YES : No action is necessary and testing is complete.
NO :  Replace the ETACS-ECU. Check that the turn-signal 

lamp indicator lamps illuminate normally.

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-339

FOG LAMP

GENERAL DESCRIPTION CONCERNING THE FOG LAMPS

M1549021400216

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

The following ECUs affect the functions and control 
of the fog lamps.

Fog lamp

The fog lamps will illuminate only when the fog lamp 
switch is operated while the low-beam headlamps 
are on.
The fog lamps will be switched off when any of the 
following conditions is met. The fog lamps will also 
be switched off automatically by headlamp automatic 
shutoff function.

• When the high-beam headlamps are switched 

on, the fog lamps will be switched off. If the 
low-beam headlamps are switched on again, the 
fog lamps will illuminate again.

• When the headlamp switch is turned off or the tail 

lamps and headlamps are off, the fog lamps will 
be switched off. If the low-beam headlamps are 
switched on again, the fog lamps will not illumi-
nate again.

Fog lamp indicator

At the same time that the fog lamps are illuminated, the 
ETACS-ECU sends a signal to illuminate the fog lamp indicator 
via the CAN bus line. The combination meter receives the 
transmitted signal and turns the fog lamp indicator on and off.

FUNCTION

CONTROL ECU

Fog lamp

ETACS-ECU, front-ECU, column switch

Fog lamp indicator

ETACS-ECU, column switch

AC306459

ON

OFF

ON

OFF

ON

OFF

ON

OFF

Tail light switch

Headlight switch

Dimmer switch

Fog light switch

ON

OFF

Fog light

AB

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-340

INSPECTION PROCEDURE J-1: Fog Light: Fog lamps do not illuminate when the fog lamp switch is 
turned on.

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 sends a fog lamp illumination 

request signal ("LAMP ON" signal) to the 
front-ECU when the fog lamp switch is turned on 
while the headlamps are illuminating at low 
beam.

• Then the front-ECU switches on its relay to illumi-

nate the fog lamps.

.

TECHNICAL DESCRIPTION (COMMENT)

If the headlamps illuminate at low beam, the fog 
lamp relay, the fog lamp switch, the front-ECU or the 
ETACS-ECU 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 fog lamp relay may be defective

• The front-ECU may be defective

• The ETACS-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

STEP 1. Check the headlamp (low-beam) operation.

Q: Do the headlamps illuminate at low beam normally?

YES : Go to Step 2.
NO :  Refer to Inspection Procedure H-2 "The headlamps 

(low-beam) do not illuminate normally 

P.54B-264

."

AC305977AC

CONNECTORS: A-05X, A-11X

A-11X

A-05X