Mitsubishi Lancer Evolution X. Manual - part 429

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-781

STEP 23. Check for open circuit between fuel pump relay 1 
connector A-28X (terminal No. 3) and ETACS-ECU 
connector C-307 (terminal No. 1).
Q: Is the harness wire in good condition?

YES : Go to Step 24.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 24. Check harness connector A-34X at MFI relay for 
damage.
Q: Is the connector in good condition?

YES : Go to Step 25.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then confirm that the 

malfunction symptom is eliminated.

STEP 25. Check for open circuit and short circuit to 
ground between fuel pump relay 1 connector A-27X 
(terminal No. 4) and MFI relay connector A-34X (terminal 
No. 2).
Q: Is the harness wire in good condition?

YES : Go to Step 26.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 26. Check for harness damage between fuel pump 
relay 1 connector A-27X (terminal No. 1) and ECM 
connector B-09 (terminal No. 51).
NOTE: Check harness after checking intermediate connector 
A-13. If intermediate connector is damaged, repair or replace it. 
Refer to GROUP 00E, Harness Connector Inspection 

P.00E-2

. 

Then check that the malfunction is eliminated.
Q: Is the harness wire in good condition?

YES : Repair harness wire between fuel pump relay 1 

connector A-27X (terminal No. 2) and MFI relay 
connector A-34X (terminal No. 2) because of harness 
damage. Then confirm that the malfunction symptom 
is eliminated.

NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 27. Check for harness damage between fuel pump 
connector D-22 (terminal No. 5) and ETACS-ECU connector 
C-314 (terminal No. 1).
Q: Is the harness wire in good condition?

YES : Go to Step 28.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom in eliminated.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-782

STEP 28. Check for harness damage between fuel pump 
circuit resistor connector A-58 (terminal No. 2) and 
ETACS-ECU connector C-307 (terminal No. 1).
Q: Is the harness wire in good condition?

YES : Go to Step 29.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 29. Check harness connector A-34X at MFI relay for 
damage.
Q: Is the connector in good condition?

YES : Go to Step 30.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then confirm that the 

malfunction symptom is eliminated.

STEP 30. Check for harness damage between MFI relay 
connector A-34X (terminal No. 2) and fuel pump resistor 
connector A-58 (terminal No. 1).
Q: Is the harness wire in good condition?

YES : Go to Step 31.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 31. Check for harness damage between fuel pump 
relay 1 connector A-27X (terminal No. 3) and ETACS-ECU 
connector C-307 (terminal No. 1).
Q: Is the harness wire in good condition?

YES : Go to Step 32.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 32. Check for harness damage between fuel pump 
relay 1 connector A-27X (terminal No. 4) and MFI relay 
connector A-34X (terminal No. 2).
Q: Is the harness wire in good condition?

YES : Go to Step 33.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-783

STEP 33. Using scan tool MB991958, check actuator test 
item 9: Fuel Pump.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the actuator test mode for item 

9, Fuel Pump.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the fuel pump operating properly?

YES : It can be assumed that this malfunction is intermittent, 

Refer to GROUP 00, How to Use Troubleshooting − 

Inspection Service Points − How to Cope with 

Intermittent Malfunctions 

P.00-15

.

NO :  Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, ID Code 
Registration Necessity Judgment Table <Vehicles 
with KOS> 

P.42B-14

 or GROUP 42C, ID Codes 

Registration Judgment Table <Vehicles with WCM> 

P.42C-10

.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-784

Inspection procedure 24: Ignition switch-ST system and starter relay system <M/T>

M

71 72 73 74 75 76 77 78 79 80 81 82

83 84 85 86 87 88 89 90 91 92 93 94

95 96 97 98 99

100 101 102 103 104

112 113 114

109

108

107

110 111

115 116

106

105

118

117

7

3

8

1

4

9

13 14

16

15

10 11 12

17 18 19

2

5 6

1

6

4

5

9

8

10 11

13

15

14

12

16

7

2 3

1 2 3
4 5 6

AK900379

1

2 1

1 2 3

4 5 6

1

2

3 4 5 6 7 8 9 10 11 12 13 14 15 16

17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

1

1

1

2

3
4

B-10

B-09

C-304

STARTER

OFF

ON

OFF

ON

1

OFF

ON

1

106

6

B-09

B-10

105

15

7

2

IG2

ST

LOCK

IG1

5

B-109 

(MU801211)

C-51

MU801669

CLUTCH
INTERLOCK
SWITCH

B-108

A-28X

3

3

1

4

2

WHITE

GREEN

GREEN

ORANGE

LIGHT

GREEN

A-39

MU802607

C-315 

MU801890

C-210

IGNITION SWITCH

AB

FUSIBLE LINK 24

1

GREEN

B-17

MU802655

1

6

ENGINE
CONTROL
MODULE

ETACS-ECU

ACC

STARTER
RELAY

BATTERY

BLA

CK

BLA

CK

BLA

CK

BLA

CK

BLA

CK-RED

BLA

CK-RED

BLUE-RED

BLUE-RED

STARTING SYSTEM CIRCUIT <M/T>

BLA

CK-RED