Mitsubishi Montero (2002-2004). Manual - part 725

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-597

STEP 5. Check for harness damage between accelerator 
pedal position sensor connector D-138 (terminal No. 1) and 
PCM connector D-135 (terminal No. 91).
Q: Is the harness wire in good condition?

YES : Go to Step 6.
NO :  Repair it. Then go to Step 11.

STEP 6. Using scan tool MB991502, read the diagnostic 
trouble code (DTC).

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) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is DTC P2121 set?

YES : Replace the PCM. Then go to Step 11.
NO :  It can be assumed that this malfunction is intermittent. 

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

P.00-6

.

AK200945

3

4

5

1

2

8

6

7

AB

CONNECTOR: D-138

HARNESS 
CONNECTOR: 
COMPONENT SIDE

D-138(GR)

AK200947

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

CONNECTOR: D-135

HARNESS CONNECTOR: 
COMPONENT SIDE

AB

PCM

D-135(GR)

ACX01539

16-PIN

MB991502

AC

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-598

STEP 7. Check the accelerator pedal position switch.
(1) Disconnect the accelerator pedal position switch connector 

D-138.

(2) Check the continuity between accelerator pedal position 

switch side connector terminal No. 4 and No. 5.

Standard value:

Continuity (foot released from accelerator pedal)
Non-continuity (accelerator pedal depressed)

Q: Is the switch operating properly?

YES : Go to Step 8.
NO :  Replace the accelerator pedal position sensor. Then 

go to Step 11.

STEP 8. Check connector D-133 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 9.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

AK200945

3

4

5

1

2

8

6

7

AB

CONNECTOR: D-138

HARNESS 
CONNECTOR: 
COMPONENT SIDE

D-138(GR)

6 7 8

1 2 3 4 5

AK201453AB

ACCELERATOR PEDAL
POSITION SWITCH
SIDE CONNECTOR

AK200939

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

52

53

54

55

56

57

58

50

51

AB

CONNECTOR: D-133

HARNESS CONNECTOR: 
COMPONENT SIDE

PCM

D-133(GR)

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-599

STEP 9. Check for short circuit to ground between 
accelerator pedal position switch connector D-138 
(terminal No. 4) and PCM connector D-133 (terminal No. 
38).
Q: Is the harness wire in good condition?

YES : Go to Step 10.
NO :  Repair it. Then go to Step 11.

STEP 10. Using scan tool MB991502, read the diagnostic 
trouble code (DTC).

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) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is DTC P2121 set?

YES : Replace the PCM. Then go to Step 11.
NO :  It can be assumed that this malfunction is intermittent. 

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

P.00-6

.

AK200945

3

4

5

1

2

8

6

7

AB

CONNECTOR: D-138

HARNESS 
CONNECTOR: 
COMPONENT SIDE

D-138(GR)

AK200939

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

52

53

54

55

56

57

58

50

51

AB

CONNECTOR: D-133

HARNESS CONNECTOR: 
COMPONENT SIDE

PCM

D-133(GR)

ACX01539

16-PIN

MB991502

AC

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-600

STEP 11. Using scan tool MB991502, read the diagnostic 
trouble code (DTC).
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is DTC P2121 set?

YES : Retry the troubleshooting.
NO :  The inspection is complete.

P2122 Accelerator Pedal Position Sensor (Main) Circuit Low Input

ACX01539

16-PIN

MB991502

AC

AK201163

VIOLET

-WHTE

YELLO

W

-RED

BLA

CK

D-138 

(MU802073)

5 V

92

2

ACCELERATOR 
PEDAL 

POSITION
SENSOR
(MAIN)

POWERTRAIN CONTROL MODULE (PCM)

114

91

3

1

Accelerator Pedal Position Sensor (Main) Circuit

9192

939495

96979899

100

105

113114

115116117

118119120

106

107108109

110111112

101102103

104

D-135

(MU803805)

6 7 8

1 2 3 4 5