Mitsubishi 380. Manual - part 21

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-81

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: Probe Harness

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-82

STEP 1. Use diagnostic tool MB991958 to select "ECU 
COMM Check" on the SWS monitor display. 
Check the ETACS-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 "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 2.
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

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-83

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 system should communicate with the 

front-ECU normally.

STEP 3. Check the battery power supply circuit to the 
front-ECU. Measure the voltage at front-ECU connector 
A-11X.
(1) Disconnect front-ECU connector A-11X and measure the 

voltage available at the relay box side of the connector.

(2) Measure the voltage between terminal 5 and ground.

• The voltage should measure approximately 12 volts 

(battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery 

positive voltage)?
YES : Go to Step 5.
NO :  Go to Step 4.

AC305977AH

CONNECTOR: A-11X

RELAY BOX SIDE 

AC305977AH

CONNECTOR: A-11X

RELAY BOX SIDE 

5

11

9

10

8 7 6

2

4 3

1

AC209865AB

CONNECTOR A-11X
(RELAY BOX SIDE)

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-84

STEP 4. Check the wiring harness between front-ECU 
connector A-11X (terminal 5) and the battery.
Q: Is the wiring harness between front-ECU connector 

A-11X (terminal 5) and the battery in good condition?
YES : No action is necessary and testing is complete.
NO :  The wiring harness may be damaged or the 

connector(s) may have loose, corroded or damaged 
terminals, or terminals pushed back in the connector. 
Repair the wiring harness as necessary. The system 
should communicate with the front-ECU normally.

STEP 5. Check front-ECU connector A-12X for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is front-ECU connector A-12X in good condition?

YES : Go to Step 6.
NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

. The system should communicate with the 

front-ECU normally.

STEP 6. Check the ground circuit to the front-ECU. 
Measure the resistance at front-ECU connector A-12X.
(1) Disconnect front-ECU connector A-12X and measure the 

resistance available at the relay box side of the connector.

(2) Measure the resistance value between terminal 21 and 

ground.

• The resistance should be 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 8.
NO :  Go to Step 7.

AC305977AH

CONNECTOR: A-11X

RELAY BOX SIDE 

AC305977

CONNCTOR: A-12X

AI

21

22

23

24

25

26

27

28

29

30

31

RELAY BOX SIDE

AC305977

CONNCTOR: A-12X

AI

21

22

23

24

25

26

27

28

29

30

31

RELAY BOX SIDE

AC209364CM

CONNECTOR A-12X
(RELAY BOX SIDE)

24

29

30

31

28 27

25

26

21

23 22