Mitsubishi Montero (2004+). Manual - part 316

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-751

STEP 10. Check for harness damage between accelerator 
pedal position sensor connector D-138 (terminal No. 3) and 
PCM connector D-135 (terminal No. 114).
Q: Is the harness wire in good condition?

YES : Go to Step 11.
NO :  Repair it. Then go to Step 12.

STEP 11. 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 12.

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)

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-752

STEP 12. 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 P2122 set?

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

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-753

DTC P2123: Accelerator Pedal Position Sensor (Main) Circuit High Input

.

CIRCUIT OPERATION

• A 5-volt power supply is applied on the APS 

(main) power terminal (terminal No. 2) from the 
PCM (terminal No. 92).
The ground terminal (terminal No. 1) is grounded 
with PCM (terminal No. 91).

• When the accelerator pedal is moved from the 

idle position to the fully opened position, the 
resistance between the APS (main) output termi-
nal (terminal No. 3) and ground terminal (terminal 
No. 1) will increase according to the rotation.

.

TECHNICAL DESCRIPTION

• The APS (main) outputs voltage which corre-

sponds to the accelerator pedal depression.

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

AK201038AF

CONNECTOR: D-135

PCM

D-135(GR)

AK200944

ACCELERATOR
PEDAL 
POSITION 
SENSOR

AB

D-138(GR)

CONNECTOR: D-138

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-754

• The PCM checks whether the voltage is within a 

specified range.

.

DESCRIPTIONS OF MONITOR METHODS
Accelerator pedal position sensor (main) output volt-

age is out of specified range.

.

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

.

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Ignition switch "ON" position.

• Accelerator pedal position sensor (sub) output 

voltage is between 0.2 and 2.5 volts.

Judgement Criteria

• Accelerator pedal position sensor (main) output 

voltage should be 4.5 volts or higher for 1 sec-
ond.

.

OBD-II DRIVE CYCLE PATTERN
None.

.

START

END

NO

NO

YES

YES

YES

NO

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 1sec

OUTPUT VOLTAGE > =4.5V

MONITORING

CONDITIONS

AK302962