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