Mitsubishi Montero (2002-2004). Manual — part 594

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-73

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 kiloohms [at −20°C (−4°F)]

5.1

− 6.5 kiloohms [at 0°C (32°F)]

2.1

− 2.7 kiloohms [at 20°C (68°F)]

0.9

− 1.3 kiloohms [at 40°C (104°F)]

0.48

− 0.68 kiloohm [at 60°C (140°F)]

0.26

− 0.36 kiloohm [at 80°C (176°F)]

(4) Apply 3M

ä 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

GROUP 13A, Procedure 6

− Other Monitor

P.13Ab-2

.

(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

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-74

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 (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 resistor decreases.

• The engine coolant temperature sensor output

voltage increases when the resistor increases
and decreases when the resistor decreases.

.

YELLO

W

-GREEN

SKY B

ULE

AK201129

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)

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-75

TECHNICAL DESCRIPTION

• The engine coolant temperature sensor converts

the engine coolant temperature to a voltage and
output it.

• The PCM checks whether this voltage is within a

specified range.

.

DTC SET CONDITIONS

Check Conditions

• 2 seconds or more have passed since the staring

sequence was completed.

Judgement Criteria

• Engine coolant temperature sensor output volt-

age has continued to be 4.6 volts or higher [cor-
responding to coolant temperature of

−45°C (−

49

°F) or lower] for 2 seconds.

.

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

• Engine coolant temperature sensor failed.

• Open or shorted engine coolant temperature sen-

sor circuit, or loose connector.

• PCM failed.

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check data list item 21:
Engine Coolant Temperature Sensor.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991502 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 11.

ACX01539

16-PIN

MB991502

AC

AK200943

1

2

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-37

B-37(B)

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-76

STEP 3. Measure the sensor supply voltage at engine
coolant temperature sensor harness side connector B-37.
(1) Disconnect the connector B-37 and measure at the harness

side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 1 and ground.

• Voltage should be between 4.5 and 4.9 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.5 and 4.9 volts?

YES : Go to Step 7.
NO : Go to Step 4.

STEP 4. Measure the sensor supply voltage at PCM
connector D-135 by backprobing.
(1) Do not disconnect the PCM connector D-135.
(2) Disconnect the engine coolant temperature sensor

connector B-37.

(3) Turn the ignition switch to the "ON" position.

(4) Measure the voltage between terminal No. 98 and ground

by backprobing.

• Voltage should be between 4.5 and 4.9 volts.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.5 and 4.9 volts?

YES : Go to Step 5.
NO : Go to Step 6.

AK200943

1

2

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-37

B-37(B)

AK000234 AL

2 1

B-37 HARNESS
CONNECTOR:
COMPONENT SIDE

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)

AK201395

9192

939495

96979899

100 101102103

104

105106

107108109

110111112

113114

115116117

118119120

AB

D-135 HARNESS
CONNECTOR:
HARNESS SIDE