Mitsubishi Montero (2002-2004). Manual — part 619

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-173

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 117) from the output terminal (terminal
No. 4) of the right bank heated oxygen sensor
(rear).

• Terminal No. 2 of the right bank heated oxygen

sensor (rear) is grounded with PCM (terminal No.
96).

.

TECHNICAL DESCRIPTION

• The output signal of the right bank heated oxygen

sensor (front) is compensated by the output sig-
nal of the right bank heated oxygen sensor (rear).

• The PCM checks for an open circuit in the right

bank heated oxygen sensor (rear) output line.

.

DTC SET CONDITIONS

Check Conditions

• 2 seconds or more have passed since the start-

ing sequence was completed.

Judgment Criteria

• Right bank heated oxygen sensor (rear) output

voltage has continued to be 1.2 volts or higher for
2 seconds.

.

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

• Short circuit in right bank heated oxygen sensor

(rear) ground line.

• PCM failed.

AK201275

CONNECTOR: C-14

C-14(GR)

AB

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

AK201038AF

CONNECTOR: D-135

PCM

D-135(GR)

AK201049

D-14

AB

CONNECTOR: D-14

AK201049

CONNECTOR: D-116

D-116

AC

AK201052

E-112

AB

CONNECTOR: E-112

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-174

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Check connector C-14 at right bank heated
oxygen sensor (rear) and connector D-135 at PCM for
damage.
Q: Is the connector in good condition?

YES : Go to Step 2.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 3.

AK201276

1

2

3

4

CONNECTOR: C-14

C-14(GR)

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)

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-175

STEP 2. Check for short circuit to power supply between
right bank heated oxygen sensor (rear) connector C-14
(terminal No. 4) and PCM connector D-135 (terminal No.
117).
NOTE: Check harness after checking intermediate connector
E-112. If intermediate connector E-112 is damaged, repair or
replace it. Refer to GROUP 00E, Harness Connector Inspec-
tion

P.00E-2

. Then go to Step 3.

Q: Is the harness wire in good condition?

YES : Replace the PCM. Then go to Step 3.
NO : Repair it. Then go to Step 3.

STEP 3. Perform the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to

GROUP 13A, Trouble Code Diagnosis

− OBD-II Drive Cycle

− Procedure 6 − Other Monitor

P.13Ab-2

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0138 set?

YES : Repeat the troubleshooting.
NO : The procedure is complete.

AK201276

1

2

3

4

CONNECTOR: C-14

C-14(GR)

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)

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-176

DTC P0139: Heated Oxygen Sensor Circuit Slow Response (bank 1, sensor 2)

WHITE

BL

ACK

BL

ACK

WHITE

BL

ACK

BL

ACK

BL

ACK

2

1

4 5 6

3

AK201133

TO PCM

FROM MFI RELAY

96

117

2

4

3

1

1

12

23 24 25 26

2

13

3

14

4

15

5

16

6

17

7

18

8

19

9

20 21 22

27 28 29 30 31 32 33

10 11

D-116

1
5

7 8

3 4
9 10

2
6

D-14

MU801335

E-112

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

POWERTRAIN CONTROL
MODULE (PCM)

9

9

5

4

7

4

3

1 2

C-14

MU802665

Right Bank Heated Oxygen Sensor (rear) Circuit

9192

939495

96979899

100

105

113114

115116117

118119120

106

107108109

110111112

101102103

104

D-135

(MU803805)