Mitsubishi Galant 9G. Manual — part 1300

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-304

DIAGNOSTIC ITEM 7: Diagnose shorts between CAN_L and H lines <Vehicles without ABS and
vehicles without 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

NOTE

: MANUAL AIR CONDITIONING SYSTEM <LOW>
: MANUAL AIR CONDITIONING SYSTEM <MIDDLE>
OR AUTOMATIC AIR CONDITIONING SYSTEM

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-305

.

TROUBLE JUDGMENT

A short circuit may be present between the CAN_L
and H lines when the resistance between the CAN
bus lines (CAN_L and H lines) is less than 2 ohms.

.

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 a ECU may be
defective.

.

TROUBLESHOOTING HINTS

• 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 powertrain control module may be defective

DIAGNOSIS

Required Special Tool:

• MB991223: Harness Set

STEP 1. Check intermediate connector C-29 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 intermediate connector C-29 in good condition?

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

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

AC305233 AU

CONNECTORS: C-10, C-15, C-22, C-121

C-121 (Y)

C-22 (Y)

C-10 (B)

C-15 (B)

AC305413

C-218 (GR)

CONNECTOR: C-218

AJ

JUNCTION BLOCK
(REAR VIEW)

AC305231AI

CONNECTOR: C-29

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-306

STEP 2. Check the lines between the CAN_L and H lines
(communication line including ECUs) of the front wiring
harness for a short circuit. Measure the resistance at
intermediate connector C-29.

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 intermediate connector C-29, and measure the

resistance at the male side (at front wiring harness side).

(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 intermediate connector

terminals 11 and 12.

OK: 120

± 20 Ω

Q: Does the resistance measure 120

± 20 Ω?

YES : If the resistance measures 120

± 20 Ω, go to Step 3.

NO : If the resistance does not measure 120

± 20 Ω> Go to

Step 26.

AC305231AI

CONNECTOR: C-29

AC204582

2 3

27

32

28

33

16

15

4 5

19

18

29

17

34

7 8

35

22

21

9 10

30

36

31

37

25

24

23

6

20

1

14

26

11

13

12

38

BX

TEST
HARNESS

TEST
HARNESS

MALE SIDE: C-29

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-307

STEP 3. Check joint connector (3) C-02 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

.

Check the joint connector at the wiring harness side for loose,
corroded or damaged terminals, or terminals pushed back in
the connector, and also check the short pin behind the connec-
tor for corrosion, deformation and delamination.
Q: Is joint connector (3) C-02 in good condition?

YES : Go to Step 4.
NO : Repair the damaged parts. Replace the joint

connector as necessary.

AC305231AP

CONNECTOR: C-02

AC209350

1

12

2

13

3

14

4

15

5

16

6

17

7

18

8

19

9

20

10

21

11

22

AB

SHORT PIN