Mitsubishi Galant 9G. Manual — part 1354

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-520

DIAGNOSTIC ITEM 16: Diagnose CAN bus lines thoroughly <Vehicles with ABS and vehicles with
multi-center display (middle-grade type)>

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.

DATA LINK
CONNECTOR

ETACS-ECU

POWERTRAIN
CONTROL
MODULE

JOINT
CONNECTOR (3)

COMBINATION
METER

A/C-ECU

SRS-ECU

ABS-ECU

MULTI CENTER
DISPLAY UNIT

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-521

.

TROUBLE JUDGMENT

If the MUT-III cannot received signals from ECUs,
CAN bus line connector(s) are broken or an open cir-
cuit has occurred.

.

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

• The wiring harness or connectors may have

loose, corroded, or damage 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 multi-center display unit (middle-grade type)

may be defective

• The ABS-ECU may be defective

• The powertrain control module may be defective

AC305206

CONNECTOR: A-02

AR

A-02 (GR)

AC306248AB

B-19 (B)

CONNECTOR: B-19

AIR
CLEANER

PCM

AC305231BZ

C-101

C-125 (B)

C-29

C-02

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

AC305233AV

CONNECTORS: C-05, C-15, C-22, C-121

C-121 (Y)

C-22 (Y)

C-15 (B)

C-05 (B)

AC305413

C-218 (GR)

CONNECTOR: C-218

AJ

JUNCTION BLOCK
(REAR VIEW)

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-522

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

• MB991970: ABS Check Harness

STEP 1. Check 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: Is data link connector C-125 in good condition?

YES : Go to Step 2.
NO : Repair the damaged parts.

AC305231AR

CONNECTOR: C-125

C-125 (B)

DIAGNOSIS

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CONTROLLER AREA NETWORK (CAN)

54C-523

STEP 2. Check the CAN bus lines at the data link
connector. Measure the resistance at the 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) Measure the resistance at the data link connector.
(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.

(4) Measure the resistance between data link connector

terminals 6 and 14.

Q: How much resistance is measured?

2 ohms or less : Diagnostic Item 9: Check the CAN_L and

H lines for a short circuit. Refer to

P.54C-360

.

No continuity : Diagnostic Item 11: Diagnose terminator

resistors at both ends. Refer to

P.54C-407

.

More than 2 ohms but continuity exists : Go to Step 3.

AC305231AR

CONNECTOR: C-125

C-125 (B)

AC204740

AC204740

AC204740

AC204740

AC204740

AC204740

AC204740

AC204740

AC204740DA

TEST
HARNESS

TEST
HARNESS

HARNESS SIDE: C-125