Mitsubishi Montero (2004+). Manual - part 312

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-735

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

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

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) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is DTC P2108 set?

YES : Replace the PCM.
NO :  It can be assumed that this malfunction is intermittent. 

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

P.00-6

.

DTC P2121: Accelerator Pedal Position Sensor (Main) Circuit Range/Performance Problem

.

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

• Refer to DTC P2122 − Accelerator Pedal Position 

Sensor (main) Circuit 

P.13A-743

.

• Refer to INSPECTION PROCEDURE 33 − Accel-

erator Pedal Position Switch Circuit 

P.13A-944

.

.

CIRCUIT OPERATION

• Refer to, DTC P2122 − Accelerator Pedal Posi-

tion Sensor (main) Circuit 

P.13A-743

.

• Refer to INSPECTION PROCEDURE 33 − Accel-

erator Pedal Position Switch Circuit 

P.13A-944

.

.

TECHNICAL DESCRIPTION

• PCM checks the APS (main) output signal char-

acteristics for abnormal conditions.

.

DESCRIPTIONS OF MONITOR METHODS

• Accelerator pedal position sensor (main) 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

.

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-736

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Ignition switch "ON" position.

• Accelerator pedal position switch: ON

• Accelerator pedal position sensor (sub) output 

voltage is 1.88 volts or less.

Judgement Criteria

• Accelerator pedal position sensor (main) output 

voltage is 1.88 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 in APS (main) circuit

• Accelerator pedal position switch failed.

• Shorted accelerator pedal position switch circuit, 

or connector 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 > =1.88V

MONITORING

CONDITIONS

AK302960

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-737

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-738

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. 1 and ground.

• Should be less than 2 ohms.

Q: Does continuity exist?

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

AK201452

D-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)