Mitsubishi Montero (2002-2004). Manual — part 635

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-237

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

• Left bank heated oxygen sensor (rear) failed.

• Open circuit in left bank heated oxygen sensor

(rear) output line.

• Open circuit in left bank heated oxygen sensor

(rear) ground line.

• PCM failed.

DIAGNOSIS

Required Special Tools:

• MB991502: Scan Tool (MUT-II)

• MD998464: Test Harness

STEP 1. Using scan tool MB991502, check data list item 59:
Left Bank Heated Oxygen Sensor Bank 2, Sensor 2 (left
rear).

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) Start the engine and run at idle.
(3) Set scan tool MB991502 to the data reading mode for item

59, Heated Oxygen Sensor Bank 2, Sensor 2 (left rear).

• Warming up the engine. When the engine is revved, the

output voltage should repeat 0 volt and 0.6 to 1.0 volt
alternately.

(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.

ACX01539

16-PIN

MB991502

AC

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-238

STEP 2. Measure the sensor output voltage at left bank
heated oxygen sensor (rear) connector C-15 by
backprobing.
(1) Do not disconnect the connector C-15.
(2) Start the engine and run at idle.

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

backprobing.

• Warming up the engine. When the engine is revved, the

output voltage should repeat 0 volt and 0.6 to 1.0 volt
alternately.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?

YES : Go to Step 3.
NO : Go to Step 7.

AK201280

1

2

3

4

CONNECTOR: C-15

C-15(B)

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

AKX01541

1 2

4

3

AV

C-15 HARNESS
CONNECTOR:
HARNESS SIDE

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-239

STEP 3. Measure the sensor output voltage at PCM
connector D-135 by backprobing.
(1) Do not disconnect the connector D-135.
(2) Start the engine and run at idle.

(3) Measure the voltage between terminal No. 116 and ground

by backprobing.

• Warming up the engine. When the engine is 2,500 r/min,

the output voltage should repeat 0 volt and 0.6 to 1.0
volt alternately.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?

YES : Go to Step 4.
NO : Go to Step 6.

AK201280

1

2

3

4

CONNECTOR: C-15

C-15(B)

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

AK201412

9192

939495

96979899

100

105

113114

115116117

118119120

106

107108109

110111112

101102103

104

D-135 HARNESS
CONNECTOR:
HARNESS SIDE

AB

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-240

STEP 4. Check harness connector C-15 at left bank heated
oxygen sensor (rear) and harness connector D-135 at PCM
for damage.
Q: Is the harness 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 15.

AK201280

1

2

3

4

CONNECTOR: C-15

C-15(B)

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

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)