Mitsubishi Grandis. Manual - part 725

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-151

YES : 

Replace engine-ECU <M/T> or 

engine-A/T-ECU <A/T>.

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Use 

Troubleshooting/Inspection Service Points 

P.00-5

).

Code No. P0304: No. 4 Cylinder Misfire Detected

OPERATION

• Refer to Code No. P0204 No. 4 Injector System 

P.13A-130

.

FUNCTION

• If a misfire occurs while the engine is running, the 

engine speed changes for an instant.

• The engine-ECU <M/T> or engine-A/T-ECU 

<A/T> checks for such changes in engine speed.

TROUBLE JUDGMENT

Check Conditions

• Engine speed is 500 − 6,500 r/min.

• Engine coolant temperature is −10°C or higher.

• Barometric pressure is 76 kPa or higher.

• Volumetric efficiency is between 30% and 55 %.

• Adaptive learning is complete for the vane which 

generates a crankshaft position signal.

• While the engine is running, excluding gear 

shifting, deceleration, sudden 
acceleration/deceleration and A/C compressor 
switching.

• The throttle deviation is −0.06 V/10 ms to +0.06 

V/10 ms.

Judgment Criteria (change in the angular 

acceleration of the crankshaft is used for 
misfire detection).

• Misfire has occurred more frequently than the 

limit during the last 200 revolutions (when the 
catalyst temperature has been 950

°C or higher).

or

• Misfire has occurred 15 times or more in the last 

1,000 revolutions (that has been equivalent to 
approximately 1.5 times the emission standard).

PROBABLE CAUSE

• Ignition system related part(s) failed

• Low compression pressure

• Failed engine-ECU <M/T>

• Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. Check the ignition coil spark.

Q: Is the check result normal?

YES : 

Go to Step 2 .

NO : 

Check ignition Circuit System (Refer to 
Inspection Procedure 26 

P.13A-355

).

STEP 2. Connector check: B-105 No. 4 injector 
connector

Q: Is the check result normal?

YES : 

 Go to Step 3 .

NO : 

Repair or replace.

STEP 3. Check No. 4 injector itself.

• Check Injector itself (Refer to 

P.13A-393

).

Q: Is the check result normal?

YES : 

 Go to Step 4 .

NO : 

Replace No. 4 injector.

AK300978

M

1

2

AM

B-105 (GR)

Harness side connector

Connector: B-105

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-152

STEP 4. Connector check: B-15X engine control 
relay connector and C-110 engine-ECU <M/T> 
connector or engine-A/T-ECU <A/T> connector

Q: Is the check result normal?

YES : 

Go to Step 5 .

NO : 

Repair or replace.

STEP 5. Check harness between B-15X (terminal 
No. 1) engine control relay connector and B-105 
(terminal No. 1) No. 4 injector connector. 

NOTE: Before checking harness, check intermediate 
connector C-116, and repair if necessary. 

• Check power supply line for damage.

Q: Is the check result normal?

YES : 

 Go to Step 6 .

NO : 

Repair.

AK300967

2

1

3

4

AC

Harness side
connector

B-15X

Connector: B-15X

Relay box’s
triangle marks

AK305618AB

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

Connector: C-110

<L.H. drive vehicles>

<R.H. drive vehicles>

C-110 (GR)

C-110 (GR)

Harness side connector

AK300967

2

1

3

4

AC

Harness side
connector

B-15X

Connector: B-15X

Relay box’s
triangle marks

AK300978

M

1

2

AM

B-105 (GR)

Harness side connector

Connector: B-105

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-153

STEP 6. Check harness between B-105 (terminal 
No. 2) No. 4 injector connector and C-110 
(terminal No. 21) engine-ECU <M/T> connector or 
engine-A/T-ECU <A/T> connector.

• Check output line for damage.

Q: Is the check result normal?

YES : 

 Go to Step 7 .

NO : 

Repair.

STEP 7. Fuel pressure measurement.

• Fuel pressure measurement (Refer to Fuel 

Pressure Test 

P.13A-383

)

Q: Is the check result normal?

YES : 

Go to Step 8 .

NO : 

Repair.

STEP 8. Check the trouble symptoms.

Q: Does trouble symptom persist?

YES : 

Replace engine-ECU <M/T> or 

engine-A/T-ECU <A/T>.

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Use 

Troubleshooting/Inspection Service 
Points

P.00-5

).

AK300978

M

1

2

AM

B-105 (GR)

Harness side connector

Connector: B-105

AK305618AB

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

Connector: C-110

<L.H. drive vehicles>

<R.H. drive vehicles>

C-110 (GR)

C-110 (GR)

Harness side connector

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-154

Code No. P0325: Detonation Sensor System

OPERATION

• The sensor signal is inputted to the engine-ECU 

<M/T> or engine-A/T-ECU <A/T> (terminal No. 
89) from the detonation sensor (terminal No. 1).

FUNCTION

• The detonation sensor detects the vibration of the 

cylinder block caused by detonation waves, and 
inputs a signal to the engine-ECU <M/T> or 
engine-A/T-ECU <A/T>.

• In response to the signal, the engine-ECU <M/T> 

or engine-A/T-ECU <A/T> provides controls to 
retard the ignition timing when the detonation 
occurs.

TROUBLE JUDGMENT

Check Conditions

• After 2 seconds have passed since the engine 

starting sequence was completed.

• Engine speed is 2,500 r/min or higher.

Judgment Criterion

• Change of detonation sensor output voltage 

(detonation sensor peak voltage in each 1/2 turn 
of the crankshaft) has not been 0.06 V or more in 
the last consecutive 200 periods.

PROBABLE CAUSE

• Failed detonation sensor

• Open/short circuit in detonation sensor circuit or 

loose connector contact

2

1

61
656667686970 717273
74757677787980 8182
8384

858687

8889

62

6364

AK305600

89

Detonation sensor

W

B

B

2

1

B-24

MU802661

C-112 

(MU803804)

Engine-ECU <M/T> or
engine-A/T-ECU <A/T>

Detonation sensor circuit

AB

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