Mitsubishi Montero Sport (2004+). Manual - part 215

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-273

NOTE: Check harness after checking intermediate connector 
C-14, C-79 and E-45. If intermediate connectors are damaged, 
repair or replace them. Refer to GROUP 00E, Harness Con-
nector 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 right bank 
heated oxygen sensor (rear) connector E-47 (terminal No. 
3) and PCM connector C-89 (terminal No. 27).

AK200492

1

2

3

4

E-47(GR)

AB

CONNECTOR: E-47

HARNESS 
CONNECTOR: 
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

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-274

NOTE: Check harness after checking intermediate connector 
C-79 and E-45. If intermediate connectors are damaged, repair 
or replace them. 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 11.
NO :  Repair it. Then go to Step 12.

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 P0141 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 P0141 set?

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-275

DTC P0150: Heated Oxygen Sensor Circuit (bank 2 sensor 1)

AK000490

Left Bank Heated Oxygen Sensor (front) Circuit

WHITE

BL

ACK

RED

BL

ACK

BL

ACK

-RED

C-91

POWERTRAIN CONTROL MODULE (PCM)

FROM MFI RELAY

TO PCM

LEFT BANK HEATED OXYGEN SENSOR (FRONT)

4

71

57

C-90

12

32

2

3

1

22

33

1 2
3 4

A-09
MU802665

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)

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

JOINT
CONNECTOR (4)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-276

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 71) from the output terminal (terminal 
No. 4) of the left bank heated oxygen sensor 
(front).

• Terminal No. 2 of the left bank heated oxygen 

sensor (front) is grounded with PCM (terminal 
No. 57).

.

TECHNICAL DESCRIPTION

• The left bank heated oxygen sensor (front) 

detects the concentration of oxygen in the 
exhaust gas; it converts that data to voltage, and 
sends it to the PCM.

• When the left bank heated oxygen sensor (front) 

begins to deteriorate, the heated oxygen sensor 
signal response deteriorates also.

• The PCM varies the air/fuel mixture to make it 

leaner and richer, and checks the response 
speed of the left bank heated oxygen sensor 
(front). In addition, the PCM also checks for an 
open circuit in the left bank heated oxygen sensor 
(front) output line.

.

DESCRIPTIONS OF MONITOR METHODS
Left bank heated oxygen sensor (front) circuit is 

switched to 5 volts intentionally when oxygen 
sensor output is low, and detects the malfunction 
if the output voltage changes to equal or greater 
than 4.5 volts. The above procedure is repeated 
when oxygen sensor is inactive.

.

MONITOR EXECUTION
Continuous

.

AK200495

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

A-09(GR)

AB

CONNECTOR: A-09

AK103912AB

CONNECTOR: C-71

C-71

AK103738AE

CONNECTORS: C-90, C-91

PCM

C-91(GR)

C-90(GR)