Mitsubishi Lancer Evolution IX. Manual - part 400

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-75

Code No. P0130: Oxygen Sensor (front) System

OPERATION

• The sensor signal is inputted to the engine-ECU 

(terminal No. 71) from the oxygen sensor (front) 
output terminal (terminal No. 4).

• The oxygen sensor (front) (terminal No. 2) is 

earthed with engine-ECU (terminal No. 49).

FUNCTION

• The oxygen sensor (front) converts the concen-

tration of oxygen in the exhaust emission into a 
voltage and inputs the signal to the engine-ECU.

• When the air-fuel ratio is richer than the theoreti-

cal air-fuel ratio, the oxygen sensor (front) out-
puts a voltage of about 1 V. When it is leaner than 
the theoretical air-fuel ratio, it outputs a voltage of 
about 0 V.

• In response to the signal, the engine-ECU con-

trols the fuel infection amount so that the air-fuel 
ratio can be equivalent to the theoretical air-fuel 
ratio.

TROUBLE JUDGMENT

Check Conditions

• After 3 or more minutes from when the engine 

has started up.

• Engine coolant temperature approximately 80°C 

or more.

• Volumetric efficiency 25% or more.

• Engine speed of 1,200 r/min. or more.

Judgment Criterion

• When the oxygen sensor (front) output voltage is 

0.2 V or less, and a power voltage of 5 V is 
applied to the oxygen sensor (front) in the 
engine-ECU, the sensor output voltage is 4.5 V or 
more.

PROBABLE CAUSES

• Failed oxygen sensor (front)

• Open/short circuit in oxygen sensor (front) circuit 

or loose connector contact

• Failed engine-ECU 

1

2

3

4

AK501805

65

43
50

42
49

41
48
60 61

64

46 47
58 59
67 68

45

56
66

52

51

44

53

62

54

63

57

55

80

87

81

94

85

82

84

93

86

98

99

74

92

73

83

88

91

95

97

96

100

89

78

71

90

76 77

75

72
79

Engine-ECU

Oxygen sensor (front)

From Engine control relay

To engine-ECU

1

2

3

4

49

B

W

71

Oxygen sensor (front) circuit

Wire colour code
B: Black  LG: Light green  G: Green  L: Blue  W: White  Y: Yellow  SB: Sky blue  BR: Brown  O: Orange  GR: Gray
R: Red  P: Pink  V: Violet  PU: Purple

AB

C-119

(MU803782)

B-113

MU802605

C-117

(MU803783)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-76

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-II/III data list

• Refer to Data List Reference Table 

P.13A-372

.

a. Item No. 11: Oxygen sensor (front)

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

− How to Use 

Troubleshooting/Inspection Service Points 

P.00-5

).

NO : 

Go to Step 2 .

STEP 2. Connector check: B-113 oxygen sensor 
(front) connector

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Repair or replace the connector.

STEP 3. Perform resistance measurement at 
B-113 oxygen sensor (front) connector

• Disconnect connector, and measure at harness 

side.

• Resistance between terminal No. 2 and earth.

OK: 2 

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 7 .

NO : 

Go to Step 4 .

AK305011

1

2

3

4

AB

Connector : B-113

Harness side 
connector

B-113(B)

Oxygen sensor(front)

AK305011

1

2

3

4

AB

Connector : B-113

Harness side 
connector

B-113(B)

Oxygen sensor(front)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-77

STEP 4. Connector check: C-119 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 5 .

NO : 

Repair or replace the connector.

STEP 5. Check harness between B-113 (terminal 
No. 2) oxygen sensor connector and C-119 
(terminal No. 49) engine-ECU connector.

• Check earthing line for open circuit and damage.

Q: Is the check result normal?

YES : 

Go to Step 6 .

NO : 

Repair the damaged harness wire.

AK501994

65

43
50

42
49

41
48
60

61

64

46

47

58

59

67

68

45

56
66

52 51

44

53

62

54

63

57

55

AB

Connector: C-119

C-119 (GR)

C-119 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK305011

1

2

3

4

AB

Connector : B-113

Harness side 
connector

B-113(B)

Oxygen sensor(front)

AK501994

65

43
50

42
49

41
48
60

61

64

46

47

58

59

67

68

45

56
66

52 51

44

53

62

54

63

57

55

AB

Connector: C-119

C-119 (GR)

C-119 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-78

STEP 6. M.U.T.-II/III data list

• Refer to Data List Reference Table 

P.13A-372

.

a. Item No. 11: Oxygen sensor (front)

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

− How to Use 

Troubleshooting/Inspection Service Points 

P.00-5

).

NO : 

Replace the engine-ECU.

STEP 7. Perform voltage measurement at B-113 
oxygen sensor (front) connector.

• Use special tool test harness (MD998464) to con-

nect connector, and measure at pick-up harness.

• Engine: After warm-up

• Ignition switch: "ON"

• Voltage between terminal No. 2 and earth.

OK: 0.5 V or less

Q: Is the check result normal?

YES : 

Go to Step 9 .

NO : 

Go to Step 8 .

STEP 8. Connector check: C-119 engine-ECU 
connector

AK305011

1

2

3

4

AB

Connector : B-113

Harness side 
connector

B-113(B)

Oxygen sensor(front)

AK501994

65

43
50

42
49

41
48
60

61

64

46

47

58

59

67

68

45

56
66

52 51

44

53

62

54

63

57

55

AB

Connector: C-119

C-119 (GR)

C-119 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK305011

1

2

3

4

AB

Connector : B-113

Harness side 
connector

B-113(B)

Oxygen sensor(front)