Mitsubishi 380. Manual - part 681

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-134

54C

DIAGNOSTIC ITEM 3: Diagnose shorts in the ground to CAN bus line <Vehicles without multi-center 
display >

NOTE: When diagnosing CAN-BUS on vehicles 
with manual transmission (M/T), disregard 
A/T-ECU and it’s wiring circuits.

NOTE: When diagnosing CAN-BUS on vehicles 
that are not equipped with a multi-centre display, 
disregard the multi-centre display and it’s wiring 
circuits.

CAUTION

When servicing a CAN bus line, ground yourself 
by touching a metal object such as an unpainted 
water pipe. If you fail to do so, a component con-
nected to the CAN bus line may be damaged.

16DB402A

A-02 (GR)

CONNECTOR: A-02 

A-02 HARNESS CONNECTOR:

16DB407A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

A/T

CONTROL

UNIT

16DB472A

C-101

C-125 (B)

C-29

C-02

CONNECTORS: C-02, C-29, C-101, C-125

16DB473A

CONNECTORS: C-15, C-121

C-121 (Y)

C-15 (B)

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DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-135

.

TROUBLE JUDGMENT

A short to ground may be present when the voltage 
between the CAN bus line (CAN_L or CAN_H) and 
body ground is less than 1.0 V. In this condition, an 
abnormal voltage may be measured at CAN_L and 
CAN_H lines.

.

COMMENTS ON TROUBLE SYMPTOM

The wiring harness wire or connectors may have 
loose, corroded, or damage terminals, or terminals 
pushed back in the connector, or an ECU may be 
defective.

.

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 ETACS-ECU may be defective

• The combination meter may be defective

• The A/C-ECU may be defective

• The SRS-ECU may be defective

• The ABS-ECU may be defective

• The A/T- ECU may be defective

• The ENGINE- ECU may be defective

NOTE: When diagnosing CAN-BUS on vehi-

cles with manual transmission (M/T), disregard 
A/T-ECU and it’s wiring circuits.

NOTE: When diagnosing CAN-BUS on vehicles 
that are not equipped with a multi-centre display, 
disregard the multi-centre display and it’s wiring 
circuits.

16DB474A

C-218 (GR)

CONNECTOR: C-218

HARNESS SIDE

JUNCTION BLOCK

(REAR VIEW)

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-136

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991219: Inspection Test Harness

• MB992045: A/T-ECU Check Harness

STEP 1. Check ENGINE- ECU connector B-21, combination 
meter connector C-101 and data link connector C-125 for 
loose, corroded or damaged terminals, or terminals 
pushed back in the connector.

CAUTION

The strand end of the twisted wire should be within 10 cm 
(4 inches) from the connector. For details refer to 

P.54C-4

.

Q: Are ENGINE- ECU connector B-21, combination meter 

connector C-101 and data link connector C-125 in good 
condition?
YES : Go to Step 2.
NO :  Repair the damaged parts.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

16DB475A

CONNECTORS: C-101, C-125

C-101

C-125

C-125 (B)

C-101 HARNESS SIDE

DIAGNOSIS

CONTROLLER AREA NETWORK (CAN)

54C-137

STEP 2. Check the CAN_H-side bus line (communication 
line including ECUs) for short to ground. Measure the 
resistance at data link connector C-125.

CAUTION

A digital multimeter should be used. For details refer to 

P.54C-4

.

CAUTION

The test wiring harness should be used. For details refer to 

P.54C-4

.

(1) Disconnect ENGINE- ECU connector B-21 and combination 

meter connector C-101, and measure the resistance at the 
harness side of data link connector C-125.

(2) Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION

Disconnect the negative battery terminal. For details refer 
to 

P.54C-4

.

(3) Disconnect the negative battery terminal.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

16DB475A

CONNECTORS: C-101, C-125

C-101

C-125

C-125 (B)

C-101 HARNESS SIDE