Mitsubishi Lancer Evolution IX. Manual - part 439

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-231

PROBABLE CAUSES

• Open/short circuit in battery back-up line circuit or 

loose connector contact

• Failed engine-ECU 

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-II/III diagnosis code

• Temporarily place the ignition switch in "LOCK" 

(OFF) position, and 10 seconds after that, place it 
in "ON" position again.

Q: Is the diagnosis code P1603 set?

YES : 

Go to Step 2 .

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to use Troubleshooting/Inspection 

Service Points 

P.00-5

).

STEP 2. Perform voltage measurement at C-119 
engine-ECU connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: "ON"

• Voltage between terminal No. 60 and earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Check intermediate connector A-13, <L.H. 

drive vehicles> or C-31 <R.H. drive 
vehicles>, and repair if necessary. If 
intermediate connector is normal, check and 
repair harness between battery and C-119 
(terminal No. 60) engine-ECU connector.

• Check power supply line for 

open/short circuit.

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-232

STEP 3. Connector check: C-119 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 4 .

NO : 

Repair or replace the connector.

STEP 4. 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

).

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-233

INSPECTION CHART FOR TROUBLE SYMPTOMS

M1131151501655

Items

Trouble symptom

Inspection 
procedure 
No.

Communication 
with M.U.T.-II/III is 
impossible

Communication with all system is not possible

1

Communication with engine-ECU only is not possible

2

Engine warning 
lamp

The engine warning lamp does not illuminate right after the ignition switch 
is turned to the "ON" position

3

The engine warning lamp remains illuminating and never goes out

4

Starting

Starting impossible
 (starter inoperative)

The starter is impossible to operate. 5

Starting impossible
(Starter operative but no initial 
combustion)

The starter is operative and cranks 
the engine, but none of initial 
combustion is in the cylinders and 
the engine is not started.

6

Starting impossible
(Initial combustion but no complete 
combustion)

The initial combustion occurs, but 
the engine stalls soon due to the 
incomplete combustion.

7

Improper starting
 (Long time to start)

It is long cranking to start the engine.

Improper idling

Unstable idling 
(Rough idling, hunting)

The engine speed is not constant 
and changeable during the idling. 
Usually, the judgment can be based 
on the movement of the tachometer 
pointer, also on the vibration 
transmitted to the steering wheel, sift 
lever, vehicle body and so on.

8

Improper idling speed

The proper idling speed is not 
satisfied.

Engine stalled during idling
 (Die out)

The engine stalls during the idling in 
no relation to the vehicle movement.

Engine stalls

The engine stalls when starting the 
car
 (Pass out)

The engine stalls during the 
operation, or when the accelerator 
pedal is depressed from the idling.

9

The engine stalls when 
decelerating

The engine stalls at the deceleration. 10

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-234

Driving

Hesitation, sag

The response of vehicle speed 
(engine speed) is delayed when the 
accelerator pedal is depressed, or 
the vehicle speed (engine speed) is 
temporarily dropped during the 
acceleration. These phenomena are 
called "hesitation" and the serious 
hesitation is called "sag".

12

Poor acceleration

The engine cannot obtain the 
acceleration corresponding to the 
degree of throttle opening although 
the engine is smooth at the constant 
speed.

Stumble

The engine speed increase is 
delayed when the accelerator pedal 
is initially depressed at the starting.

Surge

The vehicle body is repeated to 
vibrate jollity in the forward and 
backward directions at the constant 
speed or acceleration.

The feeling of impact or vibration 
when accelerating

The large impact feeling occurs at 
the acceleration.

13

The feeling of impact or vibration 
when decelerating

The large impact feeling occurs at 
the deceleration.

14

Knocking

Sharp sound like a hammer striking 
on the cylinder walls during the 
driving can be heard and wrongly 
affects the driving.

15

Ignition timing offset

The basic ignition timing is deviated 
from the datum value.

16

Stopping

Run on (Dieseling)

The engine continues to run after the 
ignition switch is in "LOCK (OFF)" 
position.

17

Exhaust gas

Odor, white smoke, black smoke, 
high-concentration CO/HC during 
idling

The exhaust gas is extremely rank 
odor, white smoke or black smoke. 
The concentration of CO & HC is 
high during the idling.

18

Charging 
performance

Battery rundown

The battery is soon rundown or the 
charging ability of battery is small.

19

Cooling 
performance

Overheating

The temperature of engine cooling 
water is extremely high.

20

Abnormal rotation of fan Motor

The fan motor is abnormally rotated 
when the ignition switch is in "ON" 
position in no relation to the engine 
cooling water temperature.

21

Items

Trouble symptom

Inspection 
procedure 
No.