Mitsubishi Montero Sport (2004+). Manual - part 228

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-325

NOTE: Check harness after checking intermediate connector 
C-14. If intermediate connector is damaged, repair or replace it. 
Refer to GROUP 00E, Harness Connector Inspection 

P.00E-2

. 

Then go to Step 12.
Q: Is the harness wire in good condition?

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

STEP 10. Check for harness damage between left bank 
heated oxygen sensor (front) connector A-09 (terminal No. 
3) and PCM connector C-89 (terminal No. 3).
Q: Is the harness wire in good condition?

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

AK200496

1

2

3

4

A-09(GR)

AB

CONNECTOR: A-09

HARNESS 
CONNECTOR: 
COMPONENT SIDE

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK103914

2

3

4

5

6

7

8

9

11

12

13

14

15

16

17

18

19

20

30

21

22

23

24

25

26

27

28

29

31

32

33

34

35

1

10

AB

CONNECTOR: C-89

C-89(GR)

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-326

STEP 11. Retest the system.
(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 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.00-7

.

STEP 12. 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 P0155 set?

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-327

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

AK303392

Left Bank Heated Oxygen Sensor (rear) Circuit

BL

ACK

BL

ACK

BL

ACK

BL

ACK

WHITE

BL

ACK

BL

ACK

BL

ACK

WHITE

WHITE

BL

ACK

-RED

BL

ACK

-RED

POWERTRAIN CONTROL MODULE (PCM)

1

10

15

2

11

3

12

4

13 14

5

16

6

17

7

18

8

19

9

20

E-44

73

57

19

5

16

10

12

8

2

7

4

2

3

1

C-91

C-90

FROM MFI RELAY

TO PCM

LEFT BANK HEATED
OXYGEN SENSOR (REAR)

1

10

15

2

11

3

12

4

13 14

5

16

6

17

7

18

8

19

9

20

E-45

E-45

47

41

42 43

48 49 50 51 52 53 54 55 56 57

46

45

44

58

59

60 61 62 63

64 65 66

C-90
(MU803781)

1

10

2 3 4 5 6 7 8 9

11

12 13 14 15 16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

C-71

71

76

77

72 73 74

75

79 80

78

81

87 88

89

91

90

92

97

98

82

93

83

94

84 85

95

86

96

C-91
(MU803782)

1 2
3 4

E-48
MU802605

6

10

2

7

8

3 4 5

9

11 12 13

1

C-79
MU801553

JOINT
CONNECTOR (4)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-328

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 73) 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. 
57).

.

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.

.

AK200497

LEFT BANK
HEATED OXYGEN
SENSOR (REAR)

E-48(B)

AB

CONNECTOR: E-48

AK103738AE

CONNECTORS: C-90, C-91

PCM

C-91(GR)

C-90(GR)

AK200018 AB

CONNECTOR: E-44

E-44

AK103912AB

CONNECTOR: C-71

C-71

AK103911AC

CONNECTOR: C-79

C-79

AK200018 AC

CONNECTOR: E-45

E-45(B)