Mitsubishi Lancer Evolution IX. Manual — part 459

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-311

STEP 16. Check harness between B-12X
(terminal No. 1, No. 2) engine control relay
connector and battery.

NOTE: Before checking harness, check intermediate
connector A-13

*1

or C-31

*2

, and repair if necessary.

• Check power supply line for damage.

Q: Is the check result normal?

YES :

Go to Step 17 .

NO :

Repair the damaged harness wire.

STEP 17. Check harness between B-12X
(terminal No. 3) engine control relay connector
and C-119 (terminal No. 57) engine-ECU
connector.

• Check earthing line for damage.

Q: Is the check result normal?

YES :

Go to Step 18 .

NO :

Repair the damaged harness wire.

AK305003

2

1

3

4

AB

Connector : B-12X

B-12X

Harness side
connector

Relay box’s
triangle marks

AK305003

2

1

3

4

AB

Connector : B-12X

B-12X

Harness side
connector

Relay box’s
triangle marks

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-312

STEP 18. Check harness between B-12X
(terminal No. 4) engine control relay connector
and C-119 (terminal No. 47 and No. 59)
engine-ECU connector.

NOTE: Before checking harness, check intermediate
connector C-105, and repair if necessary.

• Check output line for damage.

Q: Is the check result normal?

YES :

Go to Step 19 .

NO :

Repair the damaged harness wire.

STEP 19. Check the trouble symptoms.

Q: Does trouble symptom persist?

YES :

Replace the engine-ECU.

NO :

Intermittent malfunction (Refer to GROUP
00

− How to Use

Troubleshooting/Inspection Service Points

P.00-5

).

AK305003

2

1

3

4

AB

Connector : B-12X

B-12X

Harness side
connector

Relay box’s
triangle marks

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-313

Inspection Procedure 24: Fuel Pump System

AK501829

1 2 3

4 5

3 4

1 2

3 4

1 2

1 2

1

2

3

4

1 2 3
4 5 6

M

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

OFF

ON

OFF

ON

ON

OFF

15

7.5A

15A

J/B

Fuel pump
resistor

Fuel pump
relay (3)

Fuel pump
relay (1)

Fuel pump
relay (2)

Relay
box

Battery

Ignition
switch

Engine-ECU

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

NOTE

*1: L.H. drive vehicles
*2: R.H. drive vehicles

AB

B

W

W

W

R

R

R-W

B

D-12

(MU802058)

B-121

MU802601

C-113 (*1)
or
C-112 (*2)

Fuel pump
and fuel
gauge unit

4

5

4

D-34

1

1

B-120

C-221

C-223

5

1

3

2

2

1

4

1

2

4

3

4

2

1

3

D-33

C-121

(MU803784)

R-B

V

V

R-W

R-W

W

W

W

B-W

GR

21

2

C-123

14

C-214

6

2

C-211

C-208

2

C-210

1 (*1) or 12 (*2)

C-129

13

1

C-214

11

C-214

55

IG2

ST

LOCK

ACC

IG1

R

Fuel pump circuit

8

C-119

(MU803782)

B

C-123

C-123

BR (*1)
or
B (*2)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-314

OPERATION

• The battery voltage is applied to the fuel pump

relay (1) (terminal No. 3) form the ignition switch.

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

position, the battery voltage is applied to the fuel
pump relay (2) (terminal No. 1) from the fuel
pump relay 1 (terminal No. 1).

• Battery voltage is applied to the fuel pump relay

(2) (terminal No. 3) from the ignition switch.

• During cranking and while the engine is running,

the engine-ECU turns ON the power transistor in
the engine-ECU in order to earth the coil of the
fuel pump relay (2). Consequently, the fuel pump
relay 2 turns ON, and the fuel pump relay (2) (ter-
minal No. 4) supplies the battery voltage to the
fuel pump and the fuel pump circuit resistor.

• While the engine operates with a low load, the

engine-ECU turns ON the power transistor in the
engine-ECU in order to earth the coil of the fuel
pump relay (3). Consequently, the fuel pump
relay (3) turns OFF, and the fuel pump resistor
(terminal No. 2) supplies the battery voltage to
the fuel pump (terminal No. 5).

• While the engine operates with a high load, the

engine-ECU turns OFF the power transistor in
the engine-ECU, causing the fuel pump relay (3)
to turn ON. Consequently, the fuel pump relay (3)
(terminal No. 1) supplies power directly to the fuel
pump (terminal No. 5).

FUNCTION

• The engine-ECU turns the fuel pump relay ON

during cranking and engine operation, and sup-
plies the drive power to the fuel pump.

• When operating with a low load, the engine-ECU

supplies power to the fuel pump via the resistor.
When operating with a high load, power is directly
supplied and the fuel pump fuel discharge
amount is increased.

PROBABLE CAUSES

• Failed fuel pump relay

• Failed fuel pump

• Failed fuel pump resistor

• Open/short circuit in fuel pump drive circuit or

loose connector contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

NOTE:

.

*1: L.H. drive vehicles
*2: R.H. drive vehicles

STEP 1. M.U.T.-II/III actuator test

• Refer to Actuator Test Reference Table

P.13A-378

.

a. Item No. 07: Fuel pump

Q: Is the check result normal?

YES :

Go to Step 2 .

NO :

Go to Step 3 .

STEP 2. M.U.T.-II/III actuator test

• Refer to Actuator Test Reference Table

P.13A-378

.

a. Item No. 13: Fuel pump 3

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 18 .

STEP 3. Connector check: C-223 fuel pump relay
(1) connector and C-221 fuel pump relay (2)
connector.

Q: Is the check result normal?

YES :

Go to Step 4 .

NO :

Repair or replace the connector.

AK305258

2 1

3

4

AB

C-221

C-223

Harness side
connector

Junction block’s
triangle marks

Connector: C-221, C-223