Mitsubishi Montero (2002-2004). Manual - part 981

SYMPTOM PROCEDURES <AUTOMATIC TRANSMISSION>

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SYMPTOM PROCEDURES

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TROUBLESHOOTING HINTS (The most likely 
causes for this case:)

• Malfunction of the dual pressure switch

• Damaged harness, connector

• Malfunction of A/C system

• Malfunction of the PCM

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check data list item 65: 
Dual Pressure Switch.

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Start the engine and run at idle.
(3) Set scan tool MB991502 to data reading mode for item 65, 

Dual Pressure Switch.

• When the A/C is in operation, scan tool MB991502 dis-

play should be "ON."

• When the A/C is not in operation, scan tool MB991502 

display should be "OFF."

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch operating properly?

YES : It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use Troubleshooting/
Inspection Service Points 

− How to Cope with 

Intermittent Malfunction 

P.00-6

.

NO :  Go to Step 2.

STEP 2. Check dual pressure switch connector A-22 for 
loose, corroded or damaged terminals, or terminals 
pushed back in the connector.
Q: Are the connector and terminals in good condition?

YES : Go to Step 3.
NO :  Repair or replace the damaged components. Refer to 

GROUP 00E, Harness Connector Inspection 

P.00E-

2

.

ACX01539AD

MB991502

16-PIN

AC204167

CONNECTOR : A-22

AV

A-22 (BR)

A-22

1 2

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STEP 3. Measure the power supply voltage at dual 
pressure switch connector A-22.
(1) Disconnect the connector A-22 and measure at the harness 

side.

(2) Start the engine and run at idle.
(3) Operate the A/C.

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

• The voltage should measure battery positive voltage.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage battery positive voltage?

YES : Go to Step 10.
NO :  Go to Step 4.

AC204167

CONNECTOR : A-22

AV

A-22 (BR)

A-22

1 2

AC204918 AB

2 1

A-22 HARNESS CONNECTOR : 
COMPONENT SIDE

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STEP 4. Measure the power supply voltage at A/C-ECU 
connector D-23 <Vehicles with full automatic A/C> or 
automatic compressor controller connector D-119 
<Vehicles with manual A/C> by backprobing.
(1) Do not disconnect connector D-23 <Vehicles with full 

automatic A/C> or D-119 <Vehicles with manual A/C>.

(2) Start the engine and run at idle.
(3) Operate the A/C.

(4) Measure the voltage between A/C-ECU connector D-23 

terminal 5 and ground by backprobing. <Vehicles with full 
automatic A/C>
Measure the voltage between automatic compressor 
controller connector D-119 terminal 4 and ground by 
backprobing. <Vehicles with manual A/C>

• The voltage should measure battery positive voltage.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage battery positive voltage?

YES : Go to Step 8.
NO :  Go to Step 5.

AC204188

CONNECTORS : D-23, D-119

D-23 (B)

D-23, D-119

D-119 (B)

BD

20

10

19

9

17

7

16

6

14

4

3

13

5

15

11

1 2

12

8

18

8

2

1

5

3 4

6 7

9 10

20

19

18

17

16

15

14

13

12

11

8

2

1

5

3 4

6 7

9 10

20

19

18

17

16

15

14

13

12

11

AC205399

D-23 HARNESS CONNECTOR : 
COMPONENT SIDE

<VEHICLES WITH FULL AUTOMATIC A/C>

<VEHICLES WITH MANUAL A/C>

D-119 HARNESS CONNECTOR : 
COMPONENT SIDE

AB

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STEP 5. Check intermediate connector D-28, A/C-ECU 
connector D-23 <Vehicles with full automatic A/C> and 
automatic compressor controller connector D-119 
<Vehicles with manual A/C> for loose, corroded or 
damaged terminals, or terminals pushed back in the 
connector.
Q: Are the connectors and terminals in good condition?

YES : Go to Step 6.
NO :  Repair or replace the damaged components. Refer to 

GROUP 00E, Harness Connector Inspection 

P.00E-

2

.

AC204188

CONNECTORS : D-23, D-28, D-119

D-23 (B)

D-23, D-119

D-119 (B)

BE

D-28

D-28

20

10

19

9

17

7

16

6

14

4

3

13

5

15

11

1 2

12

8

18

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

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