Mitsubishi Eclipse. Manual - part 333

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-825

STEP 5. Check for open circuit and short circuit to ground 
and harness damage between generator connector B-45 
(terminal No. 1) and ECM connector C-53 (terminal No. 33) 
<M/T> or PCM connector C-50 (terminal No. 8) <A/T>.
Q: Is the harness wire in good condition?

YES : Replace the ECM or PCM. Then confirm that the 

malfunction symptom is eliminated.

NO :  Repair it. Then confirm that the malfunction symptom 

is eliminated.

AK300740

2

1

3

4

CONNECTOR: B-45

AB

B-45 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AK300417

34 33 32

36 35

37

42

45

31

39

38

46

40

41

43

44

CONNECTOR: C-53 <M/T>

C-53 (G)

AB

HARNESS CONNECTOR:
COMPONENT SIDE

AK300414

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

C-50 (GR)

CONNECTOR: C-50 <A/T>

AB

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-826

INSPECTION PROCEDURE 27: Incorrect Idle Speed When the A/C is Operating (A/C Switch 2 Signal)

.

CIRCUIT OPERATION

• The ECM <M/T> or PCM <A/T> increases the 

engine idle speed by driving the IAC motor when 
the automatic compressor-ECU sends a "A/C on" 
signal to the module.

• The automatic compressor-ECU detects how the 

air conditioning is applying load to the engine, 
and converts the information to a voltage signal 
(High voltage = low load, Low voltage = high 
load). This voltage signal is called "A/C switch 2 

signal". The ECM <M/T> or PCM <A/T> receives 
this A/C switch 2 signal from the automatic com-
pressor controller through terminal No. 24 <M/T> 
or terminal No. 61 <A/T>, and determines the 
idle-up speed according to the high or low air 
conditioning load.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this code to be set are: ) 

• Malfunction of the A/C control system.

AK000677

BL

UE-

WHITE

ENGINE CONTROL
MODULE (ECM) <M/T>
OR
POWERTRAIN CONTROL
MODULE (PCM) <A/T>

AUTOMATIC COMPRESSOR CONTROLLER

C-49 <M/T>
(MU803773)

C-54 <A/T>
(MU803781)

24 <M/T>
61 <A/T>

6

17

8

15

9

18

7

20

16

2

10

13

12

23 24 25 26

11

21

3

1

14

4

19

5

22

42 43
48 49 50 51 52 53 54 55 56 57

46

45

44

58 59

60 61 62 63

64 65 66

47

41

A/C Switch 2 signal Circuit

AK300060

ECM

CONNECTOR: C-49 <M/T>

AC

C-49 (G)

AK300060AB

C-54 (GR)

PCM

CONNECTOR: C-54 <A/T>

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-827

• Open or shorted circuit, or improper connector 

contact.

• ECM <M/T> or PCM <A/T> failed. 

DIAGNOSIS

STEP 1. Check connector C-49 at ECM <M/T> or connector 
C-54 at PCM <A/T> for damage.
Q: Is the connector in good condition?

YES :  Go to Step 2.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then confirm that the 

malfunction symptom is eliminated.

AK300413

1

14

4

19

5

22

6

17

8

15

9

18

7

20

16

2

21

23

26

24

25

3

10

11

12

13

CONNECTOR: C-49 <M/T>

C-49 (G)

AB

HARNESS CONNECTOR:
COMPONENT SIDE

AK300412

42

43

48

49

50

51

52

53

54

55

56

57

46 45 44

58

59

60

61

62

63

64

65

66

47

41

C-54 (GR)

CONNECTOR: C-54 <A/T>

AB

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-828

STEP 2. Measure the output voltage at ECM harness side 
connector C-49 <M/T> or PCM harness side connector 
C-54 <A/T>.
(1) Disconnect the connector C-49 <M/T> or C-54 <A/T> and 

measure at the harness side.

(2) Start the engine and run at idle.
(3) Turn the A/C switch "ON".

AK300413

1

14

4

19

5

22

6

17

8

15

9

18

7

20

16

2

21

23

26

24

25

3

10

11

12

13

CONNECTOR: C-49 <M/T>

C-49 (G)

AB

HARNESS CONNECTOR:
COMPONENT SIDE

AK300412

42

43

48

49

50

51

52

53

54

55

56

57

46 45 44

58

59

60

61

62

63

64

65

66

47

41

C-54 (GR)

CONNECTOR: C-54 <A/T>

AB

HARNESS CONNECTOR:
COMPONENT SIDE