Mitsubishi Grandis. Manual — part 764

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-307

STEP 4. Fuel pressure measurement.

• Fuel pressure measurement (Refer to Fuel

Pressure Test

P.13A-383

).

Q: Is the check result normal?

YES :

Replace engine-ECU <M/T> or

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

NO :

Repair.

Inspection Procedure 12: Hesitation, Sag, Poor Acceleration, Stumble, Surge

COMMENT ON TROUBLE SYMPTOM

• Failure is possibly caused by failed ignition

system, improper air-fuel ratio, throttle valve
opening control system improper compression
pressure or other faults.

PROBABLE CAUSE

• Failed air-fuel ratio control system

• Failed ignition system

• Failed fuel system

• Failed intake and exhaust system

• Failed emission control system

• Failed throttle valve opening control system

• Throttle valve fouled

• Improper compression pressure

• Failed engine-ECU <M/T>

• Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. MUT-III diagnosis code

Q: Diagnosis code set?

YES :

Inspection chart for diagnosis code (Refer

to

P.13A-20

).

NO :

Go to Step 2 .

STEP 2. Check injector for operating sound.

• Check injector for operating sound (Refer to

P.13A-393

).

Q: Can operating sound be heard?

YES :

Go to Step 3 .

NO :

Check the injector system of the defective

cylinder.

(Refer to Code No. P0201: No. 1 Injector

System

P.13A-115

).

(Refer to Code No. P0202: No. 2 Injector

System

P.13A-120

).

(Refer to Code No. P0203: No. 3 Injector

System

P.13A-125

).

(Refer to Code No. P0204: No. 4 Injector

System

P.13A-130

).

STEP 3. MUT-III data list

• Refer to Data List Reference Table

P.13A-363

.

a. Idem 13: Intake air temperature sensor
b. Item 14: Throttle position sensor (sub)

c. Item 21: Engine coolant temperature sensor

d. Item 77: Accelerator pedal position sensor

(sub)

e. Item 78: Accelerator pedal position sensor

(main)

f. Item 79: Throttle position sensor (main)

Q: Are the check results normal?

YES :

Go to Step 4 .

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 4: 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 5 .

NO :

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

STEP 5. Check purge control solenoid valve
itself.

• Check purge control solenoid valve itself (Refer

to GROUP 17

− Emission Control System −

Evaporative Emission Control System

− Purge

Control Solenoid Valve Check

P.17-62

).

Q: Is the check result normal?

YES :

Go to Step 6 .

NO :

Replace purge control solenoid valve.

STEP 6. Check EGR valve (stepper motor) itself.

• Check EGR valve (stepper motor) itself [Refer to

GROUP 17

− Emission Control System −

Exhaust Gas Recirculation (EGR) System

− EGR

Valve (Stepper Motor) Check

P.17-65

].

Q: Is the check result normal?

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-308

YES :

Go to Step 7 .

NO :

Replace EGR valve (stepper motor).

STEP 7. MUT-III data list

• Refer to Data List Reference Table

P.13A-363

.

a. Item 11: Cylinder 1, 4 oxygen sensor (front)
b. Item 39: Cylinder 2, 3 oxygen sensor (front)

c. Item 59: Cylinder 1, 4 oxygen sensor (rear)

d. Item 69: Cylinder 2, 3 oxygen sensor (rear)

Q: Are the check results normal?

YES :

Go to Step 8 .

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 8. Check ignition coil spark.

Q: Is the check result normal?

YES :

Go to Step 9 .

NO :

Check ignition circuit system (Refer to
Inspection Procedure 26

P.13A-355

).

STEP 9. Check throttle body (throttle valve
portion) for contamination.

Q: Is the check result normal?

YES :

Go to Step 10 .

NO :

Clean throttle body (throttle valve portion)
(Refer to

P.13A-383

).

STEP 10. Fuel pressure measurement.

• Fuel pressure measurement (Refer to Fuel

Pressure Test

P.13A-383

).

Q: Is the check result normal?

YES :

Go to Step 11 .

NO :

Repair.

STEP 11. Check compression pressure.

• Check compression pressure (Refer to GROUP

11A

− On-vehicle Service − Compression

Pressure Check

P.11A-13

).

Q: Is the check result normal?

YES :

Replace engine-ECU <M/T> or

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

NO :

Repair.

Inspection Procedure 13: The Feeling of Impact or Vibration when Accelerating

COMMENT ON TROUBLE SYMPTOM

• Failure is possibly caused by failed ignition leak

with rise in spark plug-required voltage at
acceleration, throttle valve opening control
system.

PROBABLE CAUSE

• Failed ignition system

• Failed throttle valve opening control system

• Failed engine-ECU <M/T>

• Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. MUT-III diagnosis code

Q: Diagnosis code set?

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 14: Throttle position sensor (sub)
b. Item 77: Accelerator pedal position sensor

(sub)

c. Item 78: Accelerator pedal position sensor

(main)

d. Item 79: Throttle position sensor (main)

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. Check ignition coil spark.

Q: Is the check result normal?

YES :

Replace engine-ECU <M/T> or

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

NO :

Check ignition circuit system (Refer to
Inspection Procedure 26

P.13A-355

).

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-309

Inspection Procedure 14: The Feeling of Impact or Vibration when Decelerating

COMMENT ON TROUBLE SYMPTOM

• Failure is possibly caused by insufficient air

intake due to failed idle speed control system.

PROBABLE CAUSE

• Failed idle speed control system

• Throttle valve body fouled

• Failed engine-ECU <M/T>

• Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. MUT-III diagnosis code

Q: Diagnosis code set?

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 14: Throttle position sensor (sub)
b. Item 77: Accelerator pedal position sensor

(sub)

c. Item 78: Accelerator pedal position sensor

(main)

d. Item 79: Throttle position sensor (main)

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. Check throttle body (throttle valve)
contamination.

Q: Is the check result normal?

YES :

Replace engine-ECU <M/T> or

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

NO :

Clean throttle body (throttle valve portion)
(Refer to

P.13A-383

).

Inspection Procedure 15: Knocking

COMMENT ON TROUBLE SYMPTOM

• Failure is possibly caused by failed detonation

control, improper thermal value of spark plug or
other faults.

PROBABLE CAUSE

• Defective detonation sensor

• Failed detonation control system

• Failed ignition system

• Defective spark plug

• Failed engine-ECU <M/T>

• Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. MUT-III diagnosis code

Q: Diagnosis code set?

YES :

Inspection chart for diagnosis code (Refer

to

P.13A-20

).

NO :

Go to Step 2 .

STEP 2. Check ignition coil spark.

Q: Is the check result normal?

YES :

Check detonation sensor system (Refer to

Code No. P0

P.13A-154

).

NO :

Check ignition circuit system (Refer to
Inspection Procedure 26

P.13A-355

).

Inspection Procedure 16: Ignition Timing Offset

COMMENT ON TROUBLE SYMPTOM

• Failure is possibly caused by failed crank angle

sensor, failed camshaft position sensor, improper

installed timing belt or other faults.

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-310

PROBABLE CAUSE

• Failed crank angle sensor

• Failed camshaft position sensor

• Improperly installed timing belt

• Failed engine-ECU <M/T>

• Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. MUT-III diagnosis code

Q: Diagnosis code set?

YES :

Inspection chart for diagnosis code (Refer

to

P.13A-20

).

NO :

Go to Step 2 .

STEP 2. Perform output wave pattern
measurement of crank angle sensor and
camshaft position sensor (Using an
oscilloscope).

Crank Angle Sensor

• Use special tool test harness (MB991658) to

connect B-121 crank angle sensor intermediate
connector, and measure at pick-up harness.

• Engine: Idling

• Transmission: Neutral <M/T> or P range <A/T>

• Voltage between terminal No. 2 and earth.

Camshaft Position Sensor

• Use special tool test harness (MB991709) to

connect B-114 camshaft position sensor
connector, and measure at pick-up harness.

• Engine: Idling

• Transmission: Neutral <M/T> or P range <A/T>

• Voltage between terminal No. 2 and earth.

OK: Output waveform timings of both
sensors are the same as the check
procedure (Refer to

P.13A-378

) using an

oscilloscope.

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?

AK304267

1

2

3

B-121 (GR)

AC

Connector: B-121

Harness
side connector

AK304269

1

2

3

AC

Connector: B-114

B-114 (B)

Harness
side connector