Mitsubishi Montero (2004+). Manual - part 318

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-759

STEP 7. Using scan tool MB991958, check data list item 78: 
Accelerator Pedal Position Sensor (main).

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 for item 

78, Accelerator Pedal Position Sensor (main).

• Output voltage is between 0.905 and 1.165 volts when 

foot is released from accelerator pedal.

• Output voltage is 4.035 volts or higher when accelerator 

pedal is fully depressed.

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

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

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

P.00-6

.

NO :  Replace the PCM. Then go to Step 8.

STEP 8. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).
(1) Connect scan tool MB991958 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.

AK302970

AB

MB991911

MB991824

MB991827

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-760

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 Position 

Sensor (Sub) Circuit 

P.13A-768

.

• Refer to Diagnostic Function − OBD-II Drive 

Cycle 

− Procedure 33 − Accelerator Pedal Posi-

tion Switch Circuit 

P.13A-944

.

.

CIRCUIT OPERATION

• Refer to DTC P2127 − Accelerator Pedal Position 

Sensor (Sub) Circuit 

P.13A-768

.

• Refer to Diagnostic Function − OBD-II Drive 

Cycle 

− Procedure 33 − Accelerator Pedal Posi-

tion Switch Circuit 

P.13A-944

.

.

TECHNICAL DESCRIPTION

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

teristics for abnormal conditions.

.

DESCRIPTIONS OF MONITOR METHODS

• Accelerator pedal position sensor (sub) output 

voltage is greater than that the specified value 
when the accelerator pedal position switch is on.

.

MONITOR EXECUTION

• Continuous

.

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Not applicable

.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-761

DTC SET CONDITIONS

Logic Flow Chart

.

Check Condition

• Ignition switch is "ON" position.

• Accelerator pedal position switch: ON

• Accelerator pedal position sensor (main) failure 

detected.

Judgement Criteria

• Accelerator pedal position sensor (sub) output 

voltage is 2.5 volts or higher for 1 second.

.

OBD-II DRIVE CYCLE PATTERN
None.

.

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

• APS failed.

• Harness damage, or connector damage in APS 

(sub) circuit.

• Accelerator pedal position switch failed.

• Shorted accelerator pedal position switch circuit, 

harness damage.

• PCM failed.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

START

END

NO

NO

YES

YES

Yes

NO

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 1sec

OUTPUT VOLTAGE > =2.5V

MONITORING

CONDITIONS

AK302963

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-762

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 kΩ

(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 : 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