Mitsubishi Lancer Evolution IX. Manual - part 388

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-27

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

Q: Is the check result normal?

YES : 

Go to Step 7 .

NO : 

Repair or replace the connector.

STEP 7. Check harness between B-105 (terminal 
No. 3) air flow sensor connector and C-119 
(terminal No. 61) engine-ECU connector.

• Check output line for short circuit.

Q: Is the check result normal?

YES : 

Go to Step 8 .

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>

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-28

STEP 8. M.U.T.-II/III data list

• Refer to Data List Reference Table 

P.13A-372

.

a. Item No. 12: Air flow 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 : 

Replace the engine-ECU.

STEP 9. Perform voltage measurement at B-105 
air flow sensor connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: "ON"

• Voltage between terminal No. 4 and earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 11 .

NO : 

Go to Step 10 .

STEP 10. Connector check: B-12X engine control 
relay connector

Q: Is the check result normal?

YES : 

Check and repair harness between B-105 

(terminal No. 4) air flow sensor connector 
and B-12X (terminal No. 4) engine control 
relay connector.

• Check power supply line for 

open/short circuit.

NO : 

Repair or replace the connector.

STEP 11. Perform resistance measurement at 
B-105 air flow sensor connector.

• Disconnect 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 14 .

NO : 

Go to Step 12 .

AK305005

3

4

5

1

2

6

7

AB

Connector : B-105

Harness side 
connector

B-105(B)

AK305003

2

1

3

4

AB

Connector : B-12X

B-12X

Harness side 
connector

Relay box’s
triangle marks

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)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-29

STEP 12. Connector check: C-121 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 13 .

NO : 

Repair or replace the connector.

STEP 13. Check harness between B-105 (terminal 
No. 5) air flow sensor connector and C-121 
(terminal No. 34) engine-ECU connector.

• Check earthing line for open circuit and damage.

Q: Is the check result normal?

YES : 

Go to Step 8 .

NO : 

Repair the damaged harness wire.

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>

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>

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-30

STEP 14. Perform voltage measurement at B-105 
air flow sensor connector.

• Use special tool test harness (MB991709) to con-

nect connector, and measure at pick-up harness.

• Ignition switch: "ON"

• Voltage between terminal No. 7 and earth.

OK: 6 

− 9 V

Q: Is the check result normal?

YES : 

Go to Step 17 .

NO : 

Go to Step 15 .

STEP 15. Connector check: C-121 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 16 .

NO : 

Repair or replace the connector.

STEP 16. Check harness between B-105 (terminal 
No. 7) air flow sensor connector and C-121 
(terminal No. 19) engine-ECU connector.

• Check reset signal line for short circuit.

Q: Is the check result normal?

YES : 

Replace the air flow sensor.

NO : 

Repair the damaged harness wire.

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>

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>