Mitsubishi Grandis. Manual - part 714

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-107

STEP 9. Check harness between B-18 (terminal 
No. 1) cylinder 2, 3 oxygen sensor (rear) 
connector and B-15X (terminal No. 1) engine 
control relay 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 10 .

NO : 

Repair.

STEP 10. Check harness between B-18 (terminal 
No. 3) cylinder 2, 3 oxygen sensor (rear) 
connector and C-110 (terminal No. 18) 
engine-ECU <M/T> connector or engine-A/T-ECU 
<A/T> connector.

• Check earthing line for damage.

Q: Is the check result normal?

YES : 

Go to Step 11 .

NO : 

Repair.

AK300977

1

2

3

4

AC

Connector: B-18

Harness side 
connector

B-18 (B)

Cylinder 2, 3
oxygen sensor
(rear)

AK300967

2

1

3

4

AC

Harness side
connector

B-15X

Connector: B-15X

Relay box’s
triangle marks

AK300977

1

2

3

4

AC

Connector: B-18

Harness side 
connector

B-18 (B)

Cylinder 2, 3
oxygen sensor
(rear)

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-108

STEP 11. 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

).

Code No. P0170: Abnormal Fuel System (Cylinder 1, 4)

OPERATION

• Refer to Code No. P0201: No. 1 Injector System 

P.13A-115

.

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

P.13A-130

.

FUNCTION

• If the fuel system goes out of order, the fuel 

correction value will become larger.

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

<A/T> checks whether the fuel trim value is within 
a specified range.

TROUBLE JUDGMENT

Check Condition

• In learning the air-fuel ratio

Judgment Criteria

• Long-term fuel trim has continued to be +12.5 % 

or higher for 10 seconds.

or

• Long-term fuel trim has continued to be -12.5 % 

or lower for 10 seconds.

PROBABLE CAUSE

• Failed intake air temperature sensor

• Failed air flow sensor

• Failed purge control solenoid valve

• Failed injector

• Air drawn in from gaps in gasket, seals, etc.

• Failed engine coolant temperature sensor

• Failed barometric pressure sensor

• Exhaust leak

• Incorrect fuel pressure

• Failed engine-ECU <M/T>

• Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. MUT-III diagnosis code

Q: Is any other diagnosis code than P0170 output?

YES : 

Inspection chart for diagnosis code (Refer 

to 

P.13A-20

).

NO : 

Go to Step 2 .

STEP 2. MUT-III data list

• Refer to Data List Reference Table 

P.13A-363

.

a. Item 12: Air flow sensor
b. Item 13: Intake air temperature sensor

c. Item 21: Engine coolant temperature sensor

Q: Are the check results normal?

YES : 

Go to Step 3 .

NO : 

Perform the diagnosis code classified check 
procedure for the sensor that has shown an 
abnormal data value (Refer to Inspection 
Chart for Diagnosis Code 

P.13A-20

).

STEP 3: MUT-III data list

• Refer to Data List Reference Table 

P.13A-363

.

a. Item 25: Barometric pressure sensor

Q: Is the check result normal?

YES : 

Go to Step 4 .

NO : 

Replace engine-ECU <M/T> or 
engine-A/T-ECU <A/T>.

STEP 4. Check throttle body (throttle valve 
portion) for contamination.

Q: Is the check result normal?

YES : 

Go to Step 5 .

NO : 

Clean throttle body (throttle valve portion) 
(Refer to 

P.13A-383

).

STEP 5. Check for intake of air from intake hose 
and inlet manifold.

Q: Is the check result normal?

YES : 

Go to Step 6 .

NO : 

Repair.

STEP 6. Check for leakage of exhaust emission 
from exhaust manifold.

Q: Is the check result normal?

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-109

YES : 

Go to Step 7 .

NO : 

Repair.

STEP 7. Connector Check: Injector connector

a. B-101 (No. 1 injector connector).
b. B-105 (No. 4 injector connector).

Q: Are the check results normal?

YES : 

Go to Step 8 .

NO : 

Repair or replace.

STEP 8. Check No.1 and No.4 injector itself.

• Check No.1 and No.4 Injector itself (Refer to 

P.13A-393

).

Q: Is the check result normal?

YES : 

Go to Step 9 .

NO : 

Replace injector.

STEP 9. 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 10 .

NO : 

Repair or replace.

AK300978

M

1

2

AH

Harness side connector

B-101 (GR)

B-105 (GR)

Connectors: B-101, B-105

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

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-110

STEP 10. Check harness between B-15X engine 
control relay connector and injector connector.

a. Check harness between B-15X (terminal No. 1) 

engine control relay connector and B-101 
(terminal No. 1) No. 1 injector connector.

b. Check harness between B-15X (terminal No. 1) 

engine control relay connector and B-105 
(terminal No. 1) No. 4 injector connector.

• Check power supply line for damage.

Q: Are the check results normal?

YES : 

Go to Step 11 .

NO : 

Repair or replace.

STEP 11. Check harness between injector 
connector and C-110 engine-ECU <M/T> 
connector or engine-A/T-ECU <A/T> connector.

a. Check harness between B-101 (terminal No. 2) 

No. 1 injector connector and C-110 (terminal No. 
1) engine-ECU <M/T> connector or 
engine-A/T-ECU <A/T> connector.

b. 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 power supply line for damage. 

Q: Are the check results normal?

YES : 

Go to Step 12 .

NO : 

Repair.

AK300978

M

1

2

AH

Harness side connector

B-101 (GR)

B-105 (GR)

Connectors: B-101, B-105

AK300967

2

1

3

4

AC

Harness side
connector

B-15X

Connector: B-15X

Relay box’s
triangle marks

AK300978

M

1

2

AH

Harness side connector

B-101 (GR)

B-105 (GR)

Connectors: B-101, 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