Mitsubishi Montero (2002-2004). Manual - part 729

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-613

STEP 8. 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 P2123 set?

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

DTC P2126: Accelerator Pedal Position Sensor (Sub) Circuit Range/Performance Problem

.

Accelerator Pedal Position Sensor (Sub) Circuit 
Range/Performance Problem Circuit

• Refer to, DTC P2127 − Accelerator Pedal Posi-

tion Sensor (Sub) Circuit 

P.13Ac-619

.

• Refer to GROUP 13A, INSPECTION PROCE-

DURE 33 

− Accelerator Pedal Position Switch 

Circuit 

P.13Ad-110

.

.

CIRCUIT OPERATION

• Refer to, DTC P2127 − Accelerator Pedal Posi-

tion Sensor (Sub) Circuit 

P.13Ac-619

.

• Refer to GROUP 13A, INSPECTION PROCE-

DURE 33 

− Accelerator Pedal Position Switch 

Circuit 

P.13Ad-110

.

.

TECHNICAL DESCRIPTION

• PCM checks the APS (sub) output signal charac-

teristics for abnormal conditions.

.

DTC SET CONDITIONS

Check Condition

• Ignition switch "ON" position.

• Accelerator pedal position switch: ON

• APS (main) failure detected.

Judgement Criteria

• APS (sub) output voltage is 2.5 volts or higher for 

1 second.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this code to be set are:)

• APS failed or maladjusted.

• Open or shorted APS (sub) circuit, or loose con-

nector.

• Accelerator pedal position switch failed or malad-

justed.

• Open or shorted accelerator pedal position switch 

circuit, or loose connector.

• PCM failed.

ACX01539

16-PIN

MB991502

AC

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-614

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Check connector D-138 at accelerator pedal 
position sensor and accelerator pedal position switch for 
damage.
Q: Is the connector in good condition?

YES : Go to Step 2.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

STEP 2. Check the accelerator pedal position sensor.
(1) Disconnect the accelerator pedal position sensor connector 

D-138.

(2) Measure resistance between terminal No. 1 and No. 2 and 

between terminal No. 7 and No. 8.

Standard value: 3.5 

− 6.5 kiloohms

(3) Measure resistance between terminal No. 2 and No. 3 and 

between terminal No. 6 and No. 8.

(4) Move the accelerator pedal from the idle position to the full-

open position.

• Resistance value changes in accordance with the accel-

erator pedal depression smoothly.

Q: Is the resistance normal?

YES : YES: Go to Step 3.
NO :  Replace the accelerator pedal position sensor.       

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)

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

AK201450

ACCELERATOR PEDAL
POSITION SENSOR
SIDE CONNECTOR

AB

6 7 8

1 2 3 4 5

AK201451

ACCELERATOR PEDAL
POSITION SENSOR
SIDE CONNECTOR

AB

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-615

STEP 3. Check the continuity at accelerator pedal position 
sensor harness side connector D-138.
(1) Disconnect the connector D-138 and measure at the 

harness side.

(2) Measure the continuity between terminal No. 7 and ground.

• Should be less than 2 ohms.

Q: Is the continuity normal?

YES : Go to Step 7.
NO :  Go to Step 4.

STEP 4. Check connector D-135 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 5.
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)

3

4

5

1

2

8

6

7

AK201455

B-138 HARNESS 
CONNECTOR: 
COMPONENT SIDE

AB

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)

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-616

STEP 5. Check for harness damage between accelerator 
pedal position sensor connector D-138 (terminal No. 7) and 
PCM connector D-135 (terminal No. 96).
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 P2126 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