Mitsubishi Lancer Evolution IX. Manual - part 392

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-43

STEP 18. Check harness between B-105 (terminal 
No. 2) air flow sensor connector and C-119 
(terminal No. 51) engine-ECU connector.

• Check output line for short circuit and damage.

Q: Is the check result normal?

YES : 

Replace the air flow sensor.

NO : 

Repair the damaged harness wire.

STEP 19. Perform voltage measurement at C-119 
engine-ECU connector.

• Measure engine-ECU terminal voltage.

• Ignition switch: "ON"

• Voltage between terminal No. 51 and earth.

OK:

Altitude 0 m: 3.8 

− 4.2 V 

Altitude 600 m: 3.5 

− 3.9 V

Altitude 1,200 m: 3.3 

− 3.7 V 

Altitude 1,800 m: 3.0 

− 3.4 V 

Q: Is the check result normal?

YES : 

Go to Step 21 . 

NO : 

Go to Step 20 . 

AK305005

3

4

5

1

2

6

7

AB

Connector : B-105

Harness side 
connector

B-105(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>

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-44

STEP 20. Connector check: C-119 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Check and repair harness between B-105 

(terminal No. 2) air flow sensor connector 
and C-119 (terminal No. 51) engine-ECU 
connector.

• Check output line for open circuit and 

damage.

NO : 

Repair or replace the connector.

STEP 21. Connector check: C-119 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 8 . 

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>

AK305005

3

4

5

1

2

6

7

AB

Connector : B-105

Harness side 
connector

B-105(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>

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-45

Code No. P0110: Intake Air Temperature Sensor System

OPERATION

• A power voltage of 5 V is applied to the intake air 

temperature sensor output terminal (terminal No. 
6) of the air flow sensor connector from the 
engine-ECU (terminal No. 62)

• The power voltage is earthed to the engine-ECU 

(terminal No. 34) from the air flow sensor (termi-
nal No. 5).

FUNCTION

• The intake air temperature sensor converts the 

intake air temperature into a voltage and inputs 
the voltage signal to the engine-ECU.

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

rects the fuel injection amount, etc.

• The intake air temperature sensor is a kind of 

resistor, which has characteristics to reduce its 
resistance as the intake air temperature rises. 
Therefore, the sensor output voltage varies with 
the intake air temperature, and becomes lower as 
the intake air temperature rises.

TROUBLE JUDGMENT

Check Condition

• 2 seconds later after the ignition switch has been 

in "ON" position or the engine has started up.

Judgment Criterion

• The sensor output voltage of 4.6 V or more 

(intake air temperature below 

−45°C or equiva-

lent) for 2 seconds.

or

• The sensor output voltage of 0.2 V or loss (intake 

air temperature above 125 

°C or equivalent) for 2 

seconds.

2 3

7

4 5 6

1

AK501802

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

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

3132 33

34 35

1

10

34

62

Engine-ECU

5

6

Intake air temperature sensor circuit

R-L

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

Intake air temperature sensor 
(Incorporated in air flow sensor)

5 V

B

B-105 

(MU802552)

C-119 

(MU803782)

AB

C-121 

(MU803783)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-46

PROBABLE CAUSES

• Failed intake air temperature sensor

• Open/short circuit in intake air temperature sen-

sor circuit or loose connector contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-II/III data list

• Item No. 13: Intake air temperature sensor

OK: At ambient temperature or equivalent.

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-105 air flow sensor 
connector

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Repair or replace the connector.

STEP 3. Check intake air temperature sensor 
itself.

• Check intake air temperature sensor itself (Refer 

to 

P.13A-403

).

Q: Is the check result normal?

YES : 

Go to Step 4 .

NO : 

Replace the air flow sensor.

STEP 4. Perform resistance measurement at 
B-105 air flow sensor connector.

• Disconnect connector, and measure at harness 

side.

• Resistance between terminal No. 5 and earth.

OK: 2 

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 8 .

NO : 

Go to Step 5 .

STEP 5. Connector check: C-121 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 6 .

NO : 

Repair or replace the connector.

AK305005

3

4

5

1

2

6

7

AB

Connector : B-105

Harness side 
connector

B-105(B)

AK305005

3

4

5

1

2

6

7

AB

Connector : B-105

Harness side 
connector

B-105(B)

AK501995

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

10

AB

Connector: C-121

C-121 (GR)

C-121 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>