Mitsubishi Galant 9G. Manual - part 1349

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-500

STEP 13. 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-501

(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

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AC204582

AC204582

HARNESS SIDE: C-02

TEST HARNESS

CG

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TEST 
HARNESS

HARNESS SIDE: C-15

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-502

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

terminal 6 and A/C-ECU connector terminal 5 <manual air 
conditioning system (low)> or 15 <manual air conditioning 
system (middle) or automatic air conditioning system>.

OK: 2 ohms or less

CAUTION

Strictly observe the specified wiring harness repair proce-
dure. For details refer to 

P.54C-5

.

Q: Do all the resistances measure 2 ohms or less?

YES : If all the resistances measure 2 ohms or less, power 

supply to the A/C-ECU may be suspected. Diagnose 
the air conditioning system. Refer to GROUP 55A, 
Manual A/C diagnosis 

P.55A-242

.

NO :  If either of the resistances measures more than 2 

ohms or all the resistances measure more than 2 
ohms, repair the wiring harness between joint 
connector (3) and the A/C-ECU connector. 

AC204582

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CH

TEST HARNESS

TEST HARNESS

HARNESS SIDE: C-02

HARNESS SIDE: C-10

AC204582

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20191817161514131211

TEST 
HARNESS

CI

HARNESS SIDE: C-15

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TEST HARNESS

HARNESS SIDE: C-02

DIAGNOSIS

TSB Revision

CONTROLLER AREA NETWORK (CAN)

54C-503

STEP 14. Check SRS-ECU connector C-121 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 SRS-ECU connector C-121 in good condition?

YES : Go to Step 15.
NO :  Repair the damaged parts.

STEP 15. Using scan tool MB991958, diagnose the CAN 
bus line (Disconnect SRS-ECU connector C-121, and 
check the supplemental restraint system).
(1) Disconnect SRS-ECU connector C-121.
(2) Turn the ignition switch to the "ON" position.

(3) Diagnose CAN bus lines, and check if the MUT-III screen is 

as shown in the illustration.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Connect the SRS-ECU connector C-121.
Q: Does the MUT-III screen correspond to the illustration?

YES  : If the MUT-III screen corresponds to the illustration, 

go to Step 16 .

NO  : If the MUT-III screen does not correspond to the 

illustration, go to Step 19.

AC305233 AJ

CONNECTOR: C-121

HARNESS SIDE

C-121 (Y)

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AC305233 AJ

CONNECTOR: C-121

HARNESS SIDE

C-121 (Y)

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AC306074

: Red section on screen

AF

MUT

ETACS

-ECU

AC-ECU

SRS-ECU

ABS-ECU

J/C

METER

-ECU

PCM