Mitsubishi Montero (2004+). Manual - part 166

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-151

STEP 5. Check for open circuit and harness damage 
between throttle position sensor connector B-05 (terminal 
No. 4) and PCM connector D-135 (terminal No. 105).
Q: Is the harness wire in good condition?

YES : Go to Step 6.
NO :  Repair it. Then go to Step 8.

AK201174

1

6 5 4 3 2

B-05(B)

CONNECTOR: B-05

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)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-152

STEP 6. Using scan tool MB991958, check data list item 79: 
Throttle 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) Detach the intake air hose at the throttle body.
(4) Disconnect the connector of the throttle position sensor.
(5) Use test harness special tool (MB991658) to connect only 

terminals No. 1, No. 2, No. 3, and No. 4.

(6) Set scan tool MB991958 to the data reading mode for item 

79, Throttle Position Sensor (main).

• Output voltage should be between 0.3 and 0.7 volt when 

the throttle valve is fully closed with your finger.

• Output voltage should be 4.0 volts or more when the 

throttle valve is fully open with your finger.

(7) 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 7. Replace the throttle body assembly.
(1) Replace the throttle body assembly.
(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 P0123 set?

YES : Replace the PCM. Then go to Step 8.
NO :  The procedure is complete.

AK302970

AB

MB991911

MB991824

MB991827

AK201174

1

6 5 4 3 2

B-05(B)

CONNECTOR: B-05

HARNESS 
CONNECTOR: 
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-153

STEP 8. 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 P0123 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-154

DTC P0125: Insufficient Coolant Temperature for Closed Loop Fuel Control

.

CIRCUIT OPERATION

• 5-volt voltage is applied to the engine coolant 

temperature sensor output terminal (terminal No. 
1) from the PCM (terminal No. 98) via the resistor 
in the PCM. The ground terminal (terminal No. 2) 
is grounded with PCM (terminal No. 96).

• The engine coolant temperature sensor is a neg-

ative temperature coefficient type of resistor. It 
has the characteristic that when the engine cool-
ant temperature rises the resistance decreases.

• The engine coolant temperature sensor output 

voltage increases when the resistance increases 
and decreases when the resistance decreases.

.

YELLO

W

-GREEN

BLA

CK

AK302923

ENGINE COOLANT
TEMPERATURE SENSOR

POWERTRAIN CONTROL MODULE(PCM)

5 V

98

2

B-37

(MU802406)

96

1

Engine Coolant Temperature Sensor Circuit

1 2

9192

939495

96979899

100

105

113114

115116117

118119120

106

107108109

110111112

101102103

104

D-135

(MU803805)

AK200942

ENGINE COOLANT
TEMPERATURE SENSOR

AK200942AB

B-37(B)

CONNECTOR: B-37

AK201038AF

CONNECTOR: D-135

PCM

D-135(GR)