Mitsubishi Eclipse. Manual - part 336

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-837

INSPECTION PROCEDURE 29: Power supply system and ignition switch 

− IG system.

AK103263

6

2 3

4 5 6

GREEN

1

1

3

2

4

1

4

8

7

2

6

3

5

5

BLA

CK-

ORANGE

BLA

CK-

ORANGE

BLA

CK-

ORANGE

RED-WHITE

RED

RED

RED

WHITE-VIOLET

RED-

WHITE

RED-

WHITE

RED-

WHITE

RED-

WHITE

WHITE

WHITE

BLA

CK

BLA

CK

BLA

CK

BATTERY

Power Supply and Ignition Switch-IG Circuit

R

IG2

ST

LOCK

ACC

IG1

C-87

    C-111
MU801331

IGNITION
SWITCH

2

6

1

82
<M/T>*3
98
<A/T>*5

     C-07
MU801333

80
<M/T>*3
66
<A/T>*4

MFI
RELAY

1

2

4

3

38
<M/T>*2
49
<A/T>*4

BATTERY
BACK UP

12
<M/T>*1
41    
<A/T>*4

25
<M/T>*1
47
<A/T>*4

POWER
SOURCE

26
<M/T>*1
48
<A/T>*4

13
<M/T>*1
42
<A/T>*4

NOTE
*1: ECM connector C-49 <M/T>
*2: ECM connector C-53 <M/T>
*3: ECM connector C-60 <M/T>
*4: PCM connector C-54 <A/T>
*5: PCM connector C-57 <A/T>

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

C-54 <A/T>
(MU803781)

C-60 <M/T>
(MU803772)

C-57 <A/T>
(MU803782)

C-53 <M/T>
(MU803771)

C-49 <M/T>
(MU803773)

3

8

9

20A

3

1

14

4

19

5

22

6

17

8

15

9

18

7

20

16

2

13

12

23 24 25 26

21

3

10 11

82

78

81

80

89 90 91 92

79

87

71

74

73

72

76

75

77

85

88

83 84

86

98

78

71

88 89

76 77

72
79
91

73
80

74

75

81
92

8283
93

8485

94

8687

9596

90

97

34

33

32

36

35

37

42

45

31

39

38

46

40 41

43 44

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

15 16

26 27 28 29

32 33 34

17 18 19 20 21 22 23 24 25

30 31

36 37

35

38

10

11 12 13

1 2 3

4 5 6 7 8 9

14

C-89

C-07

RELAY BOX

3 4

1 2

A-18X

1

6

4 5

11

10

12 13 14

8 9

7

2 3

C-112

MU801857

17

7.5A

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-838

.

CIRCUIT OPERATION

• Battery positive voltage is applied to the MFI 

relay (terminals No. 3, No. 4).

• When the ignition switch is turned to the "ON" 

position, the battery positive voltage is applied to 
the ECM (terminal No. 82) <M/T> or PCM (termi-
nal No. 98) <A/T>. When the battery positive volt-
age is applied, the ECM <M/T> or PCM <A/T> 
turns the power transistor in the ECM <M/T> or 
PCM <A/T> "ON" and grounds the MFI relay coil. 

With this, the MFI relay turns "ON" and the bat-
tery positive voltage is supplied to the ECM (ter-
minal No. 12, No. 25) <M/T> or PCM (terminal 
No. 41, No. 47) <A/T> from the MFI relay (termi-
nal No. 1).

• Battery positive voltage is constantly supplied to 

the ECM (terminal No. 80) <M/T> or PCM (termi-
nal No. 66) <A/T> as the backup power.

• The ECM (terminal No. 13, No. 26) <M/T> or 

PCM (terminals No. 42, No. 48) <A/T> is 
grounded to the vehicle body.

AK300060

ECM

CONNECTORS: C-49, C-53, C-60 <M/T>

AM

C-53 (G) C-60 (G)

C-49 (G)

AK300060

PCM

CONNECTORS: C-54, C-57 <A/T>

AI

C-57 (GR)

C-54 (GR)

AK300118

CONNECTOR: C-89

AC

C-89

AK300116

CONNECTOR: C-87

AB

C-87

AK300125

CONNECTOR: C-112

AB

C-112

AK300092

CONNECTOR: C-07

AB

C-07

AK300121

MFI RELAY

CONNECTOR: A-18X

AB

A-18X

AK300124

CONNECTOR: C-111

AB

C-111

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-839

.

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

• Malfunction of the ignition switch.

• Malfunction of the MFI relay.

• Improper connector contact, open circuit or 

short-circuited harness wire.

• Disconnected ECM <M/T> or PCM <A/T> ground 

wire.

• Malfunction of the ECM <M/T> or PCM <A/T>.

DIAGNOSIS

STEP 1. Check connector A-18X at MFI relay 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.

AK300454

2

1

3

4

CONNECTOR: A-18X

AB

A-18X

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-840

STEP 2. Check the MFI relay.
(1) Remove the MFI relay.

(2) Check for continuity between the MFI relay terminals No. 2 

and No. 3.

• There should be continuity. (approximately 70 ohms)

(3) Use jumper wires to connect MFI relay terminal No. 2 to the 

positive battery terminal and terminal No. 3 to the negative 
battery terminal.

(4) Check the continuity between the MFI relay terminals No. 1 

and No. 4 while connecting and disconnecting the jumper 
wire at the negative battery terminal.

• Should be less than 2 ohms. (Negative battery terminal 

connected)

• Should be open loop. (Negative battery terminal discon-

nected)

(5)  Install the MFI relay.
Q: Is the voltage normal?

YES : Go to Step 3.
NO :  Replace the MFI relay. Then confirm that the 

malfunction symptom is eliminated.

AK300454

2

1

3

4

CONNECTOR: A-18X

AB

A-18X

HARNESS CONNECTOR:
COMPONENT SIDE

AK204164

1

2

3

4

MFI RERAY 
SIDE 
CONNECTOR

AB

1

2

3

4

AK203257

MFI RELAY SIDE
CONNECTOR

AB