Mitsubishi Galant (2004+). Manual - part 498

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-603

TROUBLE JUDGMENT
If the MUT-III cannot received signals from the 
A/C-ECU, CAN bus line connector(s) are broken or 
an open circuit 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 the A/C-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 A/C-ECU may be defective

DIAGNOSIS

Required Special Tool:

• MB991223: Harness Set

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-604

STEP 1. Check joint connector (3) C-02 and A/C-ECU 
connector C-10 <manual air conditioning system (low)> or 
C-15 <manual air conditioning system (middle) or 
automatic air conditioning system> 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: Are joint connector (3) C-02 and A/C-ECU connector 

C-10 <manual air conditioning system (low)> or C-15 
<manual air conditioning system (middle) or automatic 
air conditioning system> in good condition?
YES : Go to Step 2.
NO :  Repair the damaged parts. Replace the joint 

connector as necessary.

AC305231AP

CONNECTOR: C-02

AC305234AB

C-10 HARNESS SIDE

C-15 HARNESS SIDE

CONNECTORS: C-10, C-15

C-10 (B)

C-15 (B)

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

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-605

STEP 2. Check the CAN bus lines between joint connector 
(3) and the A/C-ECU. Measure the resistance between joint 
connector (3) C-02 and A/C-ECU connector C-10 <manual 
air conditioning system (low)> or C-15 <manual air 
conditioning system (middle) or automatic air conditioning 

system>.

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 joint connector (3) C-02 and A/C-ECU 

connector C-10 <manual air conditioning system (low)> or 
C-15 <manual air conditioning system (middle) or automatic 
air conditioning system>, and measure the resistances at 
the wiring harness sides of joint connector (3) C-02 and 
A/C-ECU connector C-10 <manual air conditioning system 
(low)> or C-15 <manual air conditioning system (middle) or 
automatic air conditioning system>.

(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.

AC305231AP

CONNECTOR: C-02

AC305234AB

C-10 HARNESS SIDE

C-15 HARNESS SIDE

CONNECTORS: C-10, C-15

C-10 (B)

C-15 (B)

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-606

(4) Measure the resistance between joint connector (3) 

terminal 17 and A/C-ECU connector terminal 6 <manual air 

conditioning system (low)> or 14 <manual air conditioning 
system (middle) or automatic air conditioning system>.

OK: 2 ohms or less

AC204582CF

HARNESS SIDE: C-10

TEST 
HARNESS

HARNESS SIDE: C-02

TEST HARNESS

11

22

10

21

9

20

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19

7

18

6

17

5

16

4

15

3

14

2

13

1

12

AC204582

AC204582

HARNESS SIDE: C-02

TEST HARNESS

CG

11

22

10

21

9

20

8

19

7

18

6

17

5

16

4

15

3

14

2

13

1

12

TEST 
HARNESS

HARNESS SIDE: C-15