Mitsubishi Lancer Evolution IX. Manual - part 396

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-59

STEP 15. Check harness between B-107 (terminal 
No. 1) engine coolant temperature sensor 
connector and C-119 (terminal No. 44) 
engine-ECU connector.

• Check output line for damage.

Q: Is the check result normal?

YES : 

Go to Step 16 .

NO : 

Repair the damaged harness wire.

STEP 16. Connector check: C-119 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Check harness between B-107 (terminal 

No. 2) engine coolant temperature sensor 
connector and C-119 (terminal No. 49) 
engine-ECU connector.

• Check earthing line for damage.

NO : 

Repair or replace the connector.

AK305008

1

2

AB

Connector : B-107

Harness side 
connector

B-107(B)

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>

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>

AK305008

1

2

AB

Connector : B-107

Harness side 
connector

B-107(B)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-60

Code No. P0120: Throttle Position Sensor System

OPERATION

• The power voltage of 5 V is applied to the throttle 

position sensor (terminal No. 1) from the 
engine-ECU (terminal No. 42).

• The power voltage is earthed to the engine-ECU 

(terminal No. 49) from the throttle position sensor 
(terminal No. 4).

• The sensor signal is inputted to the engine-ECU 

(terminal No. 78) from the throttle position sensor 
output terminal (terminal No. 2).

FUNCTION

• The throttle position sensor converts the opening 

of the throttle valve into a voltage and inputs the 
voltage signal to the engine-ECU.

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

the opening of the throttle valve.

TROUBLE JUDGMENT

Check Condition

• Ignition switch: "ON" (Exclude 2 seconds after the 

ignition switch has been in "ON" position or just 
after the engine has started up.)

Judgment Criterion

• The sensor output voltage is 0.2 V or less for 2 

seconds.

Check Conditions

• Engine speed of 1,000 r/min. or less.

• Volumetric efficiency 60% or less.

Judgment Criterion

• The sensor output voltage is 2.0 V or more for 2 

seconds.

2 3 4

1

AK501804

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

5 V

Engine-ECU

49

78

42

B-03

(MU802724)

Throttle position sensor

1

2

4

Throttle position sensor 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

B

G

GR

C-119

(MU803782)

C-117

(MU803783)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-61

PROBABLE CAUSES

• Failed throttle position sensor

• Open/short circuit in throttle position sensor cir-

cuit or loose connector contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-II/III data list

• Refer to Data List Reference Table 

P.13A-372

.

a. Item No. 14: Throttle position sensor

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-03 throttle position 
sensor connector

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Repair or replace the connector.

STEP 3. Check throttle position sensor itself.

• Check throttle position sensor itself (Refer to 

P.13A-404

).

Q: Is the check result normal?

YES : 

Go to Step 4 .

NO : 

Replace the throttle position sensor.

STEP 4. Perform voltage measurement at B-03 
throttle position sensor connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: "ON" 

• Voltage between terminal No. 1 and earth.

OK: 4.9 

− 5.1 V

Q: Is the check result normal?

YES : 

Go to Step 10 .

NO : 

Go to Step 5 .

AK305010

2 1

3

4

AB

Connector : B-03

Harness side 
connector

B-03(B)

AK305010

2 1

3

4

AB

Connector : B-03

Harness side 
connector

B-03(B)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-62

STEP 5. Perform voltage measurement at C-119 
engine-ECU connector.

• Measure engine-ECU terminal voltage.

• Ignition switch: "ON" 

• Voltage between terminal No. 42 and earth.

OK: 4.9 

− 5.1 V

Q: Is the check result normal?

YES : 

Go to Step 6 .

NO : 

Go to Step 7 .

STEP 6. Connector check: C-119 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Check and repair harness between B-03 

(terminal No. 1) throttle position sensor 
connector and C-119 (terminal No. 42) 
engine-ECU connector.

• Check power supply line for open 

circuit.

NO : 

Repair or replace the connector.

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>

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>

AK305010

2 1

3

4

AB

Connector : B-03

Harness side 
connector

B-03(B)