Mitsubishi 380. Manual — part 100

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-397

STEP 4. Check the input signal (by using the pulse check
mode of the monitor).
Check the following switches and input signals:

• Door switches

(1) Operate diagnostic tool MB991958 according to the

procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."

(2) Check if diagnostic tool MB991958 sounds or not.

Q: When any door switch is operated, does diagnostic tool

MB991958 sound?
YES : Go to Step 5.
NO : Refer to Inspection Procedure N-3 "ETACS-ECU

does not receive any signal from any of the door
switches

P.54B-440

."

STEP 5. Replace the combination meter.
(1) Replace the combination meter.
(2) Check that the door ajar indicator lamp illuminates normally.

Q: Is the door ajar indicator lamp in good condition?

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

indicator lamp illuminates normally.

ITEM NAME

CONDITION

door switches

Open or close one of the doors

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-398

INSPECTION PROCEDURE K-7: Interior Light: The seat belt warning lamp do not illuminate or go out
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 combination meter and the ETACS-ECU illumi-
nates and flashes the seat belt warning lamp by
using the signal from the seat belt switch, the ignition
switch (IG1) and the vehicle speed signal.

.

TECHNICAL DESCRIPTION (COMMENT)

If the seat belt warning lamp does not illuminate or
flash correctly, connector(s), wiring harness in the
CAN bus lines, the door switches, the ETACS-ECU,
or the combination meter 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

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

·IGNITION SWITCH (IG1)

·SEAT BELT SWITCH

·VEHICLES SPEED

SIGNAL

COMBINATION

METER

ETACS-ECU

INPUT SIGNAL

CAN COMMUNICATION LINE

(CAN_H_LINE)

CAN COMMUNICATION LINE

(CAN_L_LINE)

Seat Belt Warning Light Circuit

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-399

STEP 1. 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 2.
NO : Repair the CAN bus line (Refer to GROUP 54C,

Diagnosis

P.54C-15

).

STEP 2. Using diagnostic tool MB991958, read the
combination meter diagnostic trouble code.
(1) Check whether the combination meter-related DTC is set.
(2) Turn the ignition switch to the "ON" position.
(3) Check whether the combination meter-related DTC is set.
(4) 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 3.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-400

STEP 3. 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 "LOCK" (OFF) 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 4.
NO : Refer to Inspection Procedure A-3 "Communication

with the ETACS-ECU is not possible

P.54B-74

."

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC302210

COLUMN SWITCH
CONNECTOR

COLUMN SWITCH
CONNECTOR AT
HARNESS SIDE

MB991812

AB