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Mitsubishi Lancer Evolution IX. Manual - part 455

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-295

STEP 11. Perform voltage measurement at C-121
engine-ECU connector.

• Disconnect connector, and measure at harness

side.

• Ignition switch: "ON"

• Voltage between terminal No. 8 and earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 12 .

NO :

Check and repair harness between B-14

(terminal No. 10) intermediate connector
and C-121 (terminal No. 8) engine-ECU
connector.

• Check output line for short circuit.

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

• Measure engine-ECU terminal voltage.

• Engine: Idling after warm-up

• Transmission: Neutral

• Radiator fan: Inactive

• Voltage between terminal No. 8 and earth.

OK: Switching the head lamps to ON from
OFF causes the voltage to increase by 0.2

−

3.5 V.

Q: Is the check result normal?

YES :

Go to Step 13 .

NO :

Replace the alternator.

STEP 13. 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

AK501995

Connector: C-121

C-121 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK401753

2 3

7 8

4 5

9 10

Connector : B-14

Male side
connector

B-14(B)

AK501995

Connector: C-121

C-121 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-296

Inspection Procedure 20: Overheating

COMMENT ON TROUBLE SYMPTOM

• Failure is possibly caused by failed engine cool-

ing system, failed fan controller, failed engine
coolant temperature sensor or other faults.

PROBABLE CAUSES

• Insufficient or deteriorated engine coolant

• Failed fan controller

• Failed engine coolant temperature sensor

• Failed thermostat

• Failed water pump

• Failed radiator core

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-II/III diagnosis code

Q: Diagnosis code set?

YES :

Inspection chart for diagnosis code (Refer

P.13A-17

NO :

Go to Step 2 .

STEP 2. Check engine coolant.
NOTE: If engine coolant level falls too early, check
for leaky spots, and repair if necessary.

• Check engine coolant (Refer to GROUP 14 −

On-vehicle Service

P.14-15

Q: Is the check result normal?

YES :

Go to Step 3 .

NO :

Replace or add engine coolant.

STEP 3. M.U.T.-II/III actuator test

• Item No. 21: Fan controller

OK: Fan motor rotating

Q: Is the check result normal?

YES :

Go to Step 4 .

NO :

Check radiator fan control relay system
(Refer to Inspection Procedure 25

P.13A-324

STEP 4. M.U.T.-II/III data list

• Item No. 21: Engine coolant temperature sensor

OK:

Engine cold state: At ambient temperature

(atmospheric temperature) or equivalent.

Engine hot state: At 80

− 120 °C

Q: Is the check result normal?

YES :

Go to Step 5 .

NO :

Check engine coolant temperature sensor
system (Refer to Code No. P0115

P.13A-52

STEP 5. Check thermostat.

• Check thermostat (Refer to GROUP 14 − Ther-

mostat

P.14-19

Q: Is the check result normal?

YES :

Go to Step 6 .

NO :

Replace the thermostat.

STEP 6. Check water pump.

• Check water pump.

Q: Is the check result normal?

YES :

Replace the radiator.

NO :

Replace the water pump.

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-297

Inspection Procedure 21: Abnormal Rotation of Fan Motor

OPERATION

• The control (duty) signal is inputted to the fan

controller (terminal No. 2) from the engine-ECU
(terminal No. 18).

FUNCTION

• The engine-ECU inputs a duty signal suitable for

the engine coolant temperature, vehicle speed
and A/C switch position to the fan controller. In
response to the signal, the fan controller controls
the rotating speeds of the radiator fan and A/C
condenser fan. (The fan speed becomes higher
as the average voltage of the terminal comes
nearer to 5 V.)

PROBABLE CAUSES

• Failed fan controller

• Open/short circuit in fan controller circuit or loose

connector contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

NOTE:

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

AK501827

1 2 3

3 4

5 6

7 8

11 12 13 14 15 16 17 18 19 20

21 22 23

24 25

26 27 28 29

3132 33

34 35

5 V

Fan controller circuit

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

Fan controller

(MU802322)

A-17

A-13 (*1)

C-31 (*2)

Engine-ECU

(MU803784)

C-121

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-298

STEP 1. Connector check: C-121 engine-ECU
connector

Q: Is the check result normal?

YES :

Go to Step 2 .

NO :

Repair or replace the connector.

STEP 2. Check at C-121 engine-ECU connector.

• Disconnect connector, and measure at harness

side.

• Ignition switch: "ON"

• Short-circuit terminal No. 18 to earth.

OK: Fan motor stops rotating.

Q: Is the check result normal?

YES :

Go to Step 3 .

NO :

Go to Step 4 .

STEP 3. 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

AK501995

Connector: C-121

C-121 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK501995

Connector: C-121

C-121 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

Content .. 453 454 455 456 ..