Mitsubishi Lancer Evolution IX. Manual - part 460

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-315

STEP 4. Connector check: B-121 fuel pump 
resistor connector.

Q: Is the check result normal? 

YES : 

Go to Step 5 .

NO : 

Repair or replace the connector.

STEP 5. Check fuel pump relay (1) and fuel pump 
relay (2).

• Fuel pump relay (1) and fuel pump relay (2), con-

tinuity check (Refer to 

P.13A-402

).

Q: Is the check result normal? 

YES : 

Go to Step 6 .

NO : 

Replace the fuel pump relay.

STEP 6. Check fuel pump resistor.

• Check fuel pump resistor (Refer to 

P.13A-403

).

Q: Is the check result normal? 

YES : 

Go to Step 7 .

NO : 

Replace the fuel pump resistor.

STEP 7. Perform voltage measurement at C-223 
fuel pump relay (1) connector.

• Remove relay, and measure at junction block 

side.

• Ignition switch: "ON"

• Voltage between terminal No. 4 and earth.

OK: System voltage

Q: Is the check result normal? 

YES : 

Go to Step 8 .

NO : 

Check intermediate connector C-129 and 

C-210 and repair if necessary. If 
intermediate connector is normal, check and 
repair harness between C-223 (terminal No. 
4) fuel pump relay (1) connector and battery.

• Check power supply line for 

open/short circuit.

STEP 8. Perform voltage measurement at C-223 
fuel pump relay (1) connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: "ON"

• Voltage between terminal No. 3 and earth.

OK: System voltage

Q: Is the check result normal? 

YES : 

Go to Step 10 .

NO : 

Go to Step 9 .

AK305259

1

2

Harness side connector

Connector: B-121

B-121(B)

B-121(B)

AB

<L. H. drive vehicles>

<R. H. drive vehicles>

AK305260

2 1

3

4

AB

C-223

Harness side
connector

Junction block’s
triangle marks

Connector: C-223

AK305260

2 1

3

4

AB

C-223

Harness side
connector

Junction block’s
triangle marks

Connector: C-223

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-316

STEP 9. Check harness between C-223 (terminal 
No. 3) fuel pump relay (1) connector and C-208 
(terminal No. 2) ignition switch connector.

NOTE: Before checking harness, check intermediate 
connector C-211 repair if necessary.

• Check power supply line for open/short circuit.

Q: Is the check result normal?

YES : 

Check ignition switch (Refer to GROUP 54 

− Ignition switch − Ignition switch − 
Inspection 

P.54A-30

).

NO : 

Repair the damaged harness wire.

STEP 10. Perform resistance measurement at 
C-223 fuel pump relay (1) connector. 

• Disconnect connector, and measure at harness 

side.

• Resistance between terminal No. 2 and earth.

OK: 2

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 11 .

NO : 

Check intermediate connector C-214, and 

repair if necessary. If intermediate 
connector normal, check and repair harness 
between C-223 (terminal No. 2) fuel pump 
relay (1) connector and body earth.

• Check earthing line for open circuit 

and damage.

AK305260

2 1

3

4

AB

C-223

Harness side
connector

Junction block’s
triangle marks

Connector: C-223

AK305251

1

2

3

4

5

6

Harness side connector

Connector: C-208

C-208

<L. H. drive vehicles>

<R. H. drive vehicles>

C-208

AB

AK305260

2 1

3

4

AB

C-223

Harness side
connector

Junction block’s
triangle marks

Connector: C-223

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-317

STEP 11. Perform voltage measurement at C-221 
fuel pump relay (2) connector.

• Remove relay, and measure at junction block 

side.

• Ignition switch: "ON"

• Voltage between terminal No. 1 and earth and 

No. 3 and earth.

OK: System voltage

Q: Is the check result normal? 

YES : 

Go to Step 12 .

NO : 

Check and repair harness between C-223 

(terminal No. 1 and No. 3) fuel pump relay 
(1) connector and C-221 (terminal No. 1 and 
No. 3) fuel pump relay (2) connector.

• Check power supply line for 

open/short circuit.

STEP 12. Perform voltage measurement at C-121 
engine-ECU connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: "ON"

• Voltage between terminal No. 21 and earth.

OK: System voltage

Q: Is the check result normal? 

YES : 

Go to Step 13 .

NO : 

Check intermediate connector C-123 and 

C-214, and repair if necessary. If 
intermediate connector normal, check and 
repair harness between C-221 (terminal No. 
2) fuel pump relay (2) connector and C-121 
(terminal No. 21) engine-ECU connector.

• Check earthing line for open/short 

circuit.

AK305261

2 1

3

4

AB

C-221

Harness side
connector

Junction block’s
triangle marks

Connector: C-221

AK305260

2 1

3

4

AB

C-223

Harness side
connector

Junction block’s
triangle marks

Connector: C-223

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>

AK305261

2 1

3

4

AB

C-221

Harness side
connector

Junction block’s
triangle marks

Connector: C-221

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-318

STEP 13. Perform voltage measurement at C-121 
engine-ECU connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: "ON"

• Voltage between terminal No. 21 and earth.

OK: Fuel pump operates (Operation sounds 
are heard)

Q: Is the check result normal? 

YES : 

Go to Step 14 .

NO : 

Replace the engine-ECU.

STEP 14. Perform voltage measurement at B-121 
fuel pump resistor connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: "ON"

• Voltage between terminal No. 1 and earth.

OK: System voltage

Q: Is the check result normal? 

YES : 

Go to Step 15 .

NO : 

Check intermediate connectors C-123, 

C-214, and repair if necessary. If 
intermediate connector are normal, check 
and repair harness between C-221 (terminal 
No. 4) fuel pump relay (2) connector and 
B-121 (terminal No. 1) fuel pump resistor 
connector.

• Check power supply line for 

open/short circuit.

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>

AK305259

1

2

Harness side connector

Connector: B-121

B-121(B)

B-121(B)

AB

<L. H. drive vehicles>

<R. H. drive vehicles>

AK305261

2 1

3

4

AB

C-221

Harness side
connector

Junction block’s
triangle marks

Connector: C-221