Mitsubishi Montero Sport (2004+). Manual - part 237

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-361

STEP 3. Check harness connector E-48 at left bank heated 
oxygen sensor (rear) and harness connector C-90, C-91 at 
PCM for damage.
Q: Is the harness connector in good condition?

YES : Replace the PCM. Then go to Step 4.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 4.

STEP 4. 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 4 − 

Heated Oxygen Sensor Monitor 

P.13A-4

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0159 set?

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

AK200498

1

2

3

4

E-48(B)

AB

CONNECTOR: E-48

HARNESS 
CONNECTOR: 
COMPONENT SIDE

LEFT BANK
HEATED OXYGEN
SENSOR (REAR)

AK104029

42

43

48

49

50

51

52

53

54

55

56

57

46 45 44

58

59

60

61

62

63

64

65

66

47

41

98

78

71

88

89

76

77

72
79
91

73
80

74

75

81
92

82

83

93

84

85

94

86

87

95

96

90

97

AB

CONNECTORS: C-90, C-91

C-90(GR) C-91(GR)

C-90 HARNESS CONNECTOR:
COMPONENT SIDE

C-91 HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-362

DTC P0161: Heated Oxygen Sensor Heater Circuit (bank 2 sensor 2)

Left Bank Heated Oxygen Sensor (rear) Circuit

AK200186

RED

RED

WHITE-

BLA

CK

WHITE-

BLA

CK

WHITE-

BLA

CK

POWERTRAIN CONTROL MODULE (PCM)

1

2

22

33

1

3

2

4

3

4

12

27

26

MFI
RELAY

LEFT BANK HEATED OXYGEN
SENSOR (REAR)

FUSIBLE LINK (12)

TO PCM TO PCM

C-59

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-14

10

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

C-89
(MU803784)

YELLO

W

-

BLA

CK

RED

RED

YELLO

W

-

BLA

CK

YELLO

W

-

BLA

CK

17

6

6

1

1

10

15

2

11

3

12

4

13 14

5

16

6

17

7

18

8

19

9

20

E-45

RED

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 (5)

1

2

3

4

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-363

.

CIRCUIT OPERATION

• Power is supplied from the MFI relay (terminal 

No. 1) to the left bank heated oxygen sensor 
(rear) heater.

• The PCM (terminal No. 26) controls continuity to 

the left bank heated oxygen sensor (rear) heater 
by turning the power transistor in the PCM "ON" 
and "OFF".

.

BACKGROUND

• The PCM checks whether the heater current is 

within a specified range when the heater is ener-
gized.

.

DESCRIPTIONS OF MONITOR METHODS
Left bank heated oxygen sensor heater (rear) current 

is out of specified range when engine coolant 
temperature is over 20

°C (68°F).

.

AK103911AB

CONNECTOR: C-14

C-14

AK103911AC

CONNECTOR: C-79

C-79

AK200018 AC

CONNECTOR: E-45

E-45(B)

AK201000

MFI RELAY

CONNECTOR: C-59

AB

C-59

AK103738AD

CONNECTOR: C-89

PCM

C-89(GR)

AK200497

LEFT BANK
HEATED OXYGEN
SENSOR (REAR)

E-48(B)

AB

CONNECTOR: E-48

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-364

MONITOR EXECUTION
Continuous

.

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Engine coolant temperature sensor

.

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• 60 seconds have elapsed from the start of the 

previous monitoring.

• Engine coolant temperature is higher than 20°C 

(68

°F).

• While the left bank heated oxygen sensor (rear) 

heater is on.

• Battery positive voltage is between 11 and 16.5 

volts.

Judgment Criteria

• Heater current of the left bank heated oxygen 

sensor (rear) heater has continued to be lower 
than 0.16 ampere or higher than 5.0 ampere for 4 
seconds.

.

START

END

YES

YES

YES

YES

NO

NO

NO

NO

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 4secs

MONITORING

CONDITIONS

CURRENT < 0.16A

CURRENT > 5.0A

AK301443