Mitsubishi Montero (2004+). Manual - part 635

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-29

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

• MB991911: MUT-III Main Harness B (Vehicles without 

CAN communication system)

STEP 1. Communication check with other systems.
Q: Is communication with other systems possible using 

scan tool MB991958?
YES :  Go to Step 8.
NO :   Go to Step 2.

STEP 2. Measure the voltage at data link connector D-118. 

(1) Disconnect data link connector D-118, and measure the 

voltage at the harness side.

(2) Measure the voltage between terminal 16 and ground.

• The measured value should be approximately 12 volts 

(battery positive voltage).

Q: Does the measured voltage correspond with this range?

YES :  Go to Step 5.
NO :   Go to Step 3.

STEP 3. Check data link connector D-118 for damage.

Q: Is data link connector D-118 in good condition?

YES : Go to Step 4.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. Scan 

tool MB991958 should communicate with the vehicle 
system.

AC204170

CONNECTOR : D-118

AN

HARNESS 
SIDE

D-118(B)

D-118(B)

1

9

2

10

3

11

4

12

5

13

6

14

7

15

8

16

AC204738 DC

HARNESS SIDE : D-118

8

16

7

15

6

14

5

13

4

12

3

11

2

10

1

9

AC204170

CONNECTOR : D-118

AN

HARNESS 
SIDE

D-118(B)

D-118(B)

1

9

2

10

3

11

4

12

5

13

6

14

7

15

8

16

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-30

STEP 4. Check the wiring harness between data link 
connector D-118 (terminal 16) and the fusible link (2).

NOTE: Also check intermediate connector D-28 and junction 
block connectors D-211 and D-210. If intermediate connector 
D-28, junction block connectors D-211 or D-210 is damaged, 
repair or replace the connector as described in GROUP 00E, 
Harness Connector Inspection 

P.00E-2

.

Q: Is the wiring harness between data link connector D-118 

(terminal 16) and the fusible link (2) in good condition?
YES : Scan tool MB991958 should communicate with the 

vehicle system.

NO :  Repair the wiring harness. Scan tool MB991958 

should communicate with the vehicle system.

AC204188

CONNECTORS : D-28, D-118

D-118(B)

D-118(B)

HARNESS SIDE

CE

D-28

D-28

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

8

16

7

15

6

14

5

13

4

12

3

11

2

10

1

9

AC204191

CONNECTORS : D-210, D-211

AI

D-210

D-210

D-211(B)

D-211(B)

HARNESS SIDE

HARNESS SIDE

1

2

7 6

3

9

4

11

12

10

13

5

8

1

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-31

STEP 5. Measure the resistance at data link connector 
D-118.
(1) Disconnect data link connector D-118, and measure the 

resistance at the wiring harness side.

(2) Measure the resistance value between terminal 4, 5 and 

ground.

• 2 ohms or less

Q: Does the measured resistance value correspond with 

this range?
YES : Replace scan tool MB991958. Scan tool MB991958 

should communicate with the vehicle system.

NO :   Go to Step 6.

STEP 6. Check data link connector D-118 for damage.

Q: Is data link connector D-118 in good condition?

YES : Go to Step 7.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. Scan 

tool MB991958 should communicate with the vehicle 
system.

STEP 7. Check the wiring harness between data link 
connector D-118 (terminal 4, 5) and ground.

Q: Is the wiring harness between data link connector D-118 

(terminal 4, 5) and ground in good condition?
YES : Scan tool MB991958 should communicate with the 

vehicle system.

NO :  Repair the wiring harness. Scan tool MB991958 

should communicate with the vehicle system.

AC204170

CONNECTOR : D-118

AN

HARNESS 
SIDE

D-118(B)

D-118(B)

1

9

2

10

3

11

4

12

5

13

6

14

7

15

8

16

AC204738

1

9

2

10

3

11

4

12

5

13

6

14

7

15

8

16

AC204738 EK

HARBESS SIDE : D-118

AC204170

CONNECTOR : D-118

AN

HARNESS 
SIDE

D-118(B)

D-118(B)

1

9

2

10

3

11

4

12

5

13

6

14

7

15

8

16

AC204170

CONNECTOR : D-118

AN

HARNESS 
SIDE

D-118(B)

D-118(B)

1

9

2

10

3

11

4

12

5

13

6

14

7

15

8

16

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-32

STEP 8. Check data link connector D-118, A/C-ECU 
connector D-23 and D-24 for damage.

Q: Is data link connector D-118, A/C-ECU connector D-23 

and D-24 in good condition?
YES : Go to Step 9.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. Scan 

tool MB991958 should communicate with the vehicle 
system.

STEP 9. Check the wiring harness between data link 
connector D-118 (terminal 11, 1), A/C-ECU connector D-23 
(terminal 19) and D-24 (terminal 33).

AC204188

CONNECTORS : D-23, D-24, D-118

D-118(B)

D-118(B)

HARNESS SIDE

D-24(B)

HARNESS SIDE

D-23(B)

HARNESS SIDE

CF

D-24(B)

D-23(B)

8

16

7

15

6

14

5

13

4

12

3

11

2

10

1

9

1

3

4

2

12

1413

11

6

7

8

10 9

18

19

20

16

17

5

15

22

23

30

31

25

26

33

34

32

24

28

3635

27

29

21

AC204188

CONNECTORS : D-23, D-24, D-118

D-118(B)

D-118(B)

HARNESS SIDE

D-24(B)

HARNESS SIDE

D-23(B)

HARNESS SIDE

CF

D-24(B)

D-23(B)

8

16

7

15

6

14

5

13

4

12

3

11

2

10

1

9

1

3

4

2

12

1413

11

6

7

8

10 9

18

19

20

16

17

5

15

22

23

30

31

25

26

33

34

32

24

28

3635

27

29

21