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. P0325 

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