Mitsubishi Montero (2004+). Manual - part 160

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-127

Judgement Criteria

• Engine coolant temperature sensor output volt-

age has continued to be 0.1 volt or lower [corre-
sponding to coolant temperature of 140

°C 

(284

°F) or higher] for 2 seconds.

.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13A-4

.

.

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

• Engine coolant temperature sensor failed.

• Shorted engine coolant temperature sensor cir-

cuit, harness damage, 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

STEP 1. Using scan tool MB991958, check data list item 21: 
Engine Coolant Temperature Sensor.

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 

21, Engine Coolant Temperature Sensor.

• The engine coolant temperature and temperature 

shown with the scan tool should approximately match.

(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 :  Go to Step 2.

STEP 2. Check connector B-37 at the engine coolant 
temperature sensor for damage.
Q: Is the connector in good condition?

YES : Go to Step 3.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 6.

AK302970

AB

MB991911

MB991824

MB991827

AK200943

1

2

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

CONNECTOR: B-37

B-37(B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-128

STEP 3. Check for short circuit to ground between engine 
coolant temperature sensor connector B-37 (terminal No. 
1) and PCM connector D-135 (terminal No. 98).
Q: Is the harness wire in good condition?

YES : Go to Step 4.
NO :  Repair it. Then go to Step 6.

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 6.

AK200943

1

2

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

CONNECTOR: B-37

B-37(B)

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)

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-129

STEP 5. Check the engine coolant temperature sensor.
(1) Disconnect the engine coolant temperature sensor 

connector B-37.

(2) Remove the engine coolant temperature sensor.

(3) With the temperature sensing portion of engine coolant 

temperature sensor immersed in hot water, check 
resistance.

Standard value:

14 

− 17 kΩ [at −20°C (−4°F)]

5.1 

− 6.5 kΩ [at 0°C (32°F)]

2.1 

− 2.7 kΩ [at 20°C (68°F)]

0.9 

− 1.3 kΩ [at 40°C (104°F)]

0.48 

− 0.68 kΩ [at 60°C (140°F)]

0.26 

− 0.36 kΩ [at 80°C (176°F)]

(4) Apply 3M

 AAD part number 8731 or equivalent on the 

screw section of the engine coolant temperature sensor.

(5) Install the engine coolant temperature sensor, and tighten 

to the specified torque.

Tightening torque: 29 

± 10 N⋅m (22 ± 7 ft-lb)

Q: Is the resistance at the standard value?

YES : Replace the PCM. Then go to Step 6.
NO :  Replace the engine coolant temperature sensor. Then 

go to Step 6.

STEP 6. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− OBD-II Drive Cycle − Procedure 6 − 

Other Monitor 

P.13A-4

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0117 set?

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

AK200943

1

2

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

CONNECTOR: B-37

B-37(B)

AKX01622

AKX01623 AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-130

DTC P0118: Engine Coolant Temperature Circuit High Input

.

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

C

K

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)