Mitsubishi Montero (2004+). Manual - part 959

TRANSFER DIAGNOSIS <ACTIVE TRAC AWD II>

TSB Revision

AUTOMATIC TRANSMISSION

23A-411

DTC SET CONDITIONS
If accelerator pedal position sensor output voltage is 
0.2 volt or lower at times other than when the engine 
is idling, the output is judged to be too low and DTC 
21 is set.

.

TROUBLESHOOTING HINTS (THE MOST LIKELY 
CAUSES FOR THIS CODE TO BE SET ARE:)

• Malfunction of the accelerator pedal position sen-

sor circuit

• Damaged harness, connector

• Malfunction of the transfer-ECU

DIAGNOSIS

Required Special Tool:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

STEP 1. Using scan tool MB991958, check data list item 01: 
Accelerator Pedal Position Sensor.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to data reading mode.

• Item 01: Accelerator Pedal Position Sensor − Active trac 

4WD II.

• With the throttle valve in idle position, voltage should 

measure between 905 and 1,165 mV.

• With the throttle valve in full-open position, voltage 

should measure 4,035 mV or more.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 905 and 1,165 mV at 

idle, and 4,035 mV or more in the full-open position?
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.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

TRANSFER DIAGNOSIS <ACTIVE TRAC AWD II>

TSB Revision

AUTOMATIC TRANSMISSION

23A-412

STEP 2. Using scan tool MB991958, read the MFI 
diagnostic trouble code.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check for MFI diagnostic trouble code.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are MFI DTCs P2126, P2127 or P2128 set?

YES : Refer to GROUP 13A, Diagnosis 

− Diagnostic 

Trouble Code Chart 

P.13A-26

.

NO :  Go to Step 3.

STEP 3. Measure the accelerator pedal position sensor 
output voltage at transfer-ECU connector E-109 by 
backprobing.
(1) Do not disconnect connector E-109.
(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 5 and ground by 

backprobing.

• With the throttle valve in idle position, voltage should 

measure between 0.905 and 1.165 volts.

• With the throttle valve in full-open position, voltage 

should measure between 4.035 volts or more.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 0.535 and 0.735volt at 

idle, and between 4.5 and 5.5 volts in the full-open 
position?
YES : Go to Step 6.
NO :  Go to Step 4.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

AC204176

CONNECTOR : E-109

BB

11 12

25

24

13

26

9

22

7

6

20

19

8

21

10

23

5

4

17

2

1

15

14

3

16

18

AC204918

11 12

25

24

13

26

9

22

7

6

20

19

8

21

10

23

5

4

17

2

1

15

14

3

16

18

CC

E-109 HARNESS CONNECTOR : 
HARNESS SIDE

TRANSFER DIAGNOSIS <ACTIVE TRAC AWD II>

TSB Revision

AUTOMATIC TRANSMISSION

23A-413

STEP 4. Check transfer-ECU connector E-109 and 
intermediate connector E-114 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 5.
NO :  Repair or replace the damaged components. Refer to 

GROUP 00E, Harness Connector Inspection 

P.00E-2

.

STEP 5. Check harness for open circuit or damage 
between accelerator pedal position sensor connector 
D-138 terminal 6 and transfer-ECU connector E-109 
terminal 5.
Q: Is the harness wire in good condition?

YES : Go to Step 7.
NO :  Repair or replace the harness wire.

AC204194

CONNECTORS : E-109, E-114

BH

11 12

25

24

13

26

9

22

7

6

20

19

8

21

10

23

5

4

17

2

1

15

14

3

16

18

E-109

E-114

E-109

E-114

38

28

16

33

22

10

31

19

7

1

18

30

29

17

5

6

21

20

32

8

2

9

25

13

3

24

23

3435

1112

27

26

3637

14

4

15

AC203914

AD

STEERING
SHAFT

CONNECTOR : D-138

D-138 (GR)

1

3

2

4

6

5

7 8

AC204176

CONNECTOR : E-109

BB

11 12

25

24

13

26

9

22

7

6

20

19

8

21

10

23

5

4

17

2

1

15

14

3

16

18

TRANSFER DIAGNOSIS <ACTIVE TRAC AWD II>

TSB Revision

AUTOMATIC TRANSMISSION

23A-414

STEP 6. Check transfer-ECU connector E-109 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 7.
NO :  Repair or replace the damaged components. Refer to 

GROUP 00E, Harness Connector Inspection 

P.00E-2

.

STEP 7. Using scan tool MB991958, check data list item 01: 
Accelerator Pedal Position Sensor.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the data reading mode.

• Item 01: Accelerator Pedal Position Sensor − Active trac 

4WD II.

• With the throttle valve in idle position, voltage should 

measure between 905 and 1,165 mV.

• With the throttle valve in full-open position, voltage 

should measure 4,035 mV or more.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 905 and 1,165 mV at 

idle, and 4,035 mV or more in the full-open position?
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 :  Replace the transfer-ECU.

AC204176

CONNECTOR : E-109

BB

11 12

25

24

13

26

9

22

7

6

20

19

8

21

10

23

5

4

17

2

1

15

14

3

16

18

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR