Mitsubishi Montero Sport (2004+). Manual - part 194

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-189

STEP 10. Check the right bank heated oxygen sensor 
(front).
(1) Disconnect the right bank heated oxygen sensor (front) 

connector A-07 and connect test harness special tool, 
MD998464, to the connector on the right bank heated 
oxygen sensor (front) side.

(2) Warm up the engine until engine coolant 80

°C (176°F) or 

higher.

(3) Perform a tracing for 5 minutes or more with the engine 

speed of 4,500 r/min.

(4) Connect a digital volt meter between terminal No. 2 (black 

clip) and terminal No. 4 (white clip).

(5) While repeatedly revving the engine, measure the right 

bank heated oxygen sensor (front) output voltage.

Standard value: 0.6 

− 1.0 volt

CAUTION

• Be very careful when connecting the jumper wire; 

incorrect connection can damage the oxygen sensor.

• Be careful the heater is broken when voltage of beyond 

8 volts is applied to the oxygen sensor heater.
NOTE: If the sufficiently high temperature (of approximate 
400

°

C or more) is not reached although the oxygen sensor 

is normal, the output voltage would be possibly low 
although the rich air-fuel ratio. Therefore, if the output volt-
age is low, use a jumper wire to connect the terminal No.1 
(red clip of special tool) and the terminal No. 3 (blue clip of 
special tool) of the oxygen sensor with a (+) terminal and (-) 
terminal of 8 volts power supply respectively, then check 
again.

Q: Is the voltage at the standard value?

YES : Replace the PCM. Then go to Step 11.
NO :  Replace the right bank heated oxygen sensor (front). 

Then go to Step 11.

AK200490

1

2

3

4

A-07(B)

AB

CONNECTOR: A-07

HARNESS 
CONNECTOR: 
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MD998464

WHITE

BLACK

AL

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-190

STEP 11. 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 P0130 set?

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

DTC P0131: Heated Oxygen Sensor Circuit Low Voltage (bank 1, sensor 1)

BLA

CK

BLA

CK

WHITE

BLA

CK-RED

AK000444

Right Bank Heated Oxygen Sensor (front) Circuit

4

POWERTRAIN CONTROL MODULE (PCM)

12

2

3

1

18

57

72

RIGHT BANK HEATED OXYGEN
SENSOR (FRONT)

TO PCM

FROM MFI RELAY

C-90

C-91

1 2
3 4

A-07
MU802605

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)

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

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-191

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 72) from the output terminal (terminal 
No. 4) of the right bank heated oxygen sensor 
(front).

• Terminal No. 2 of the right bank heated oxygen 

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

.

TECHNICAL DESCRIPTION

• The right bank heated oxygen sensor (front) 

detects the concentration of oxygen in the 
exhaust gas; it converts those data to voltage, 
and inputs the resulting signals to the PCM.

• When the right bank heated oxygen sensor 

(front) begins to deteriorate, the heated oxygen 
sensor signal response becomes poor.

• The PCM forcibly varies the air/fuel mixture to 

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

.

DESCRIPTIONS OF MONITOR METHODS
Right bank heated oxygen sensor (front) output volt-

age stays low when air/fuel ratio is forced to be 
rich. The above procedure is repeated when oxy-
gen sensor is inactive.

.

MONITOR EXECUTION
Continuous

.

AK200489

A-07(B)

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AB

CONNECTOR: A-07

AK103912AB

CONNECTOR: C-71

C-71

AK103738AE

CONNECTORS: C-90, C-91

PCM

C-91(GR)

C-90(GR)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-192

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Heated oxygen sensor heater (front) monitor

• Misfire monitor

• Fuel system monitor

Sensor (The sensor below is determined to be 

normal)

• Volume airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

• Throttle position sensor

.