Mitsubishi Montero (2002-2004). Manual - part 634

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-233

STEP 9. Check for harness damage between MFI relay 
connector B-22X (terminal No. 1) and left bank heated 
oxygen sensor (front) connector B-26 (terminal No. 1).
Q: Is the harness wire in good condition?

YES : Go to Step 10.
NO :  Repair it. Then go to Step 12.

AK200951

2 1

3

4

B-22X

AB

CONNECTOR: B-22X

HARNESS 
CONNECTOR: 
COMPONENT SIDE

AK201278

1

2

3

4

CONNECTOR: B-26

B-26(GR)

AB

HARNESS 
CONNECTOR: 
COMPONENT 
SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-234

STEP 10. Check for harness damage between left bank 
heated oxygen sensor (front) connector B-26 (terminal No. 
3) and PCM connector D-132 (terminal No. 10).
Q: Is the harness wire in good condition?

YES : Go to Step 11.
NO :  Repair it. Then go to Step 12.

STEP 11. Check the trouble symptoms.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

GROUP 13A, Procedure 6 

− Other Monitor 

P.13Ab-2

.

(2) Read in the diagnostic trouble code (DTC).
Q: Is DTC P0155 set?

YES : Replace the PCM. Then go to Step 12.
NO :  It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use Troubleshooting/
Inspection Service Points 

P.00-6

 .

AK201278

1

2

3

4

CONNECTOR: B-26

B-26(GR)

AB

HARNESS 
CONNECTOR: 
COMPONENT 
SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK200938

2

3

4

5

6

7

8

9

1

10

14

15

16

17

18

19

20

21

22

23

24

25

26

27

11

12

13

AB

CONNECTOR: D-132

HARNESS CONNECTOR: 
COMPONENT SIDE

PCM

D-132(GR)

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-235

STEP 12. 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 P0155 set?

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

DTC P0156: Heated Oxygen Sensor Circuit (bank 2, sensor 2)

WHITE

BL

ACK

BL

ACK

WHITE

BL

ACK

BL

ACK

BL

ACK

AK201137

TO PCM

FROM MFI RELAY

96

116

2

4

3

1

2

1

4 5 6

3

E-112

LEFT BANK
HEATED OXYGEN
SENSOR (REAR)

POWERTRAIN CONTROL
MODULE (PCM)

10

9

1

3

7

4

3

1 2

C-15

MU802605

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

Left Bank Heated Oxygen Sensor (rear) Circuit

9192

939495

96979899

100

105

113114

115116117

118119120

106

107108109

110111112

101102103

104

D-135

(MU803805)

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-236

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 116) from the output terminal (terminal 
No. 4) of the left bank heated oxygen sensor 
(rear).

• Terminal No. 2 of the left bank heated oxygen 

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

.

TECHNICAL DESCRIPTION

• The output signal of the left bank heated oxygen 

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

• The PCM checks for an open circuit in the left 

bank heated oxygen sensor (rear) output line.

.

DTC SET CONDITIONS

Check Conditions

• 3 minutes or more have passed since the starting 

sequence was completed.

• Left bank heated oxygen sensor (rear) signal volt-

age has continued to be 0.15 volt or lower.

• Engine coolant temperature is higher than 76°C 

(169

°F).

• Engine speed is higher than 1,200 r/min.

• Volumetric efficiency is higher than 25 percent.

• Monitoring time: 7 seconds.

Judgment Criteria

• Input voltage supplied to the PCM interface circuit 

is higher than 4.5 volts when 5 volts is applied to 
the left bank heated oxygen sensor (rear) output 
line via a resistor.

• The PCM monitors for this condition once during 

the drive cycle.

.

AK201279

CONNECTOR: C-15

C-15(B)

AB

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

AK201049

CONNECTOR: D-116

D-116

AC

AK201049

D-14

AB

CONNECTOR: D-14

AK201038AF

CONNECTOR: D-135

PCM

D-135(GR)

AK201052

E-112

AB

CONNECTOR: E-112