Mitsubishi Lancer Evolution IX. Manual - part 404

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-91

STEP 6. M.U.T.-II/III data list

• Refer to Data List Reference Table 

P.13A-372

.

a. Item No. 59: Oxygen sensor (rear)

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 C-137 
oxygen sensor (rear) connector.

• Use special tool test harness (MB991658) 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

Q: Is the check result normal?

YES : 

Check and repair harness between C-137 

(terminal No. 2) oxygen sensor (rear) 
connector and C-119 (terminal No. 49) 
engine-ECU connector.

• Check earthing line for damage.

NO : 

Repair or replace the connector.

AK305013

2 1

3

4

AB

Oxygen sensor(rear)

Connector : C-137

Harness side 
connector

C-137

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>

AK305013

2 1

3

4

AB

Oxygen sensor(rear)

Connector : C-137

Harness side 
connector

C-137

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-92

STEP 9. Perform voltage measurement at C-137 
oxygen sensor (rear) connector.

• Use special tool test harness (MB991658) to con-

nect connector, and measure at pick-up harness.

• Engine: After warm-up

• Voltage between terminal No. 1 and earth.

OK:

600 

− 1,000 mV when 200 mV or lower abrupt 

racing is done a few seconds after abrupt 
deceleration from 4,000 r/min.

Q: Is the check result normal?

YES : 

Go to Step 12 .

NO : 

Go to Step 10 .

STEP 10. Check oxygen sensor (rear) itself

• Check oxygen sensor (rear) itself (Refer to 

P.13A-404

).

Q: Is the check result normal?

YES : 

 Go to Step 11 .

NO : 

Replace the oxygen (rear) sensor.

STEP 11. Connector check: C-117 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Check and repair harness between C-137 

(terminal No. 1) oxygen sensor (rear) 
connector and C-117 (terminal No. 73) 
engine-ECU connector.

• Check output line for damage.

NO : 

Repair or replace the connector.

AK305013

2 1

3

4

AB

Oxygen sensor(rear)

Connector : C-137

Harness side 
connector

C-137

AK501996

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

AB

Connector: C-117

C-117 (GR)

C-117 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK305013

2 1

3

4

AB

Oxygen sensor(rear)

Connector : C-137

Harness side 
connector

C-137

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-93

STEP 12. Perform voltage measurement at C-117 
engine-ECU connector.

• Measure engine-ECU terminal voltage.

• Transmission: Neutral

• Engine: After warm-up

• Voltage between terminal No. 73 and earth.

OK:

600 

− 1,000 mV when 200 mV or lower abrupt 

racing is done a few seconds after abrupt 
deceleration from 4,000 r/min.

Q: Is the check result normal?

YES : 

Go to Step 14 .

NO : 

Go to Step 13 .

STEP 13. Connector check: C-117 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Check and repair harness between C-137 

(terminal No. 1) oxygen sensor (rear) 
connector and C-117 (terminal No. 73) 
engine-ECU connector.

• Check output line for open circuit.

NO : 

Repair or replace the connector.

AK501996

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

AB

Connector: C-117

C-117 (GR)

C-117 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK501996

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

AB

Connector: C-117

C-117 (GR)

C-117 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK305013

2 1

3

4

AB

Oxygen sensor(rear)

Connector : C-137

Harness side 
connector

C-137

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-94

STEP 14. Connector check: C-117 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 6 .

NO : 

Repair or replace the connector.

AK501996

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

AB

Connector: C-117

C-117 (GR)

C-117 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>