Mitsubishi Montero Sport (2004+). Manual - part 343

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-785

STEP 4. Using scan tool MB991958, check data list and 
actuator test.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check the following items in the data list. Refer to Data List 

Reference Table 

P.13A-839

.

a. Item 13: Intake Air Temperature Sensor.
b. Item 25: Barometric pressure Sensor.

c. Item 21: Engine Coolant Temperature Sensor.

d. Item 14: Throttle Position Sensor.
e. Item 69: Right Bank Heated Oxygen Sensor (rear)

f. Item 39: Right Bank Heated Oxygen Sensor (front)

g. Item 59: Left Bank Heated Oxygen Sensor (rear)
h. Item 11: Left Bank Heated Oxygen Sensor (front)

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are they operating properly?

YES : Go to Step 5.
NO :  Repair or replace. Then confirm that the malfunction 

symptom is eliminated.

STEP 5. Using scan tool MB991958, check actuator test.
(1) Turn the ignition switch to the "ON" position.
(2) Check the following items in the actuator test. Refer to 

Actuator Test Reference Table 

P.13A-854

.

a. Item 10: EGR Vacuum Regulator Solenoid Valve.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?

YES : Go to Step 6.
NO :  Repair or replace. Then confirm that the malfunction 

symptom is eliminated.

AK303629AB

MB991911

MB991827

MB991824 

16-PIN

AK303629AB

MB991911

MB991827

MB991824 

16-PIN

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-786

STEP 6. Using scan tool MB991958, check data list.
(1) Turn the ignition switch to the "ON" position.
(2) Check the following items of data list. Refer to Data List 

Reference Table 

P.13A-839

.

a. Item 39: Right Bank Heated Oxygen Sensor (front)
b. Item 11: Left Bank Heated Oxygen Sensor (front)

• Voltage should fluctuate between 0 − 0.4 volt and 0.6 − 

1.0 volt while idling after the engine has been warmed.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

YES : Go to Step 8.
NO :  Go to Step 7.

STEP 7. Check the fuel pressure.
Refer to On-vehicle Service 

− Fuel Pressure Test 

P.13A-884

.

Q: Is the fuel pressure normal?

YES : Check the following items, and repair or replace the 

defective items.

a. Vacuum leak.

• Broken intake manifold gasket.

• Broken air intake hose.

• Broken vacuum hose.

• Positive crankcase ventilation valve does 

not operate.

b. Injector clogged.

Then confirm that the malfunction symptom is 

eliminated.

NO :  Repair or replace. Then confirm that the malfunction 

symptom is eliminated.

AK303629AB

MB991911

MB991827

MB991824 

16-PIN

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-787

STEP 8. Check the fuel pressure.
Refer to On-vehicle Service 

− Fuel Pressure Test 

P.13A-884

.

Q: Is the fuel pressure normal?

YES : Check the following items, and repair or replace the 

defective items.

a. Check the ignition coil, spark plugs, spark plug 

cables.

b. Check the EGR system.

Then confirm that the malfunction symptom is 

eliminated.

NO :  Repair or replace. Then confirm that the malfunction 

symptom is eliminated.

INSPECTION PROCEDURE 20: Knocking

.

COMMENT

• Incase such as the above, the heat value of the 

spark plug may be inappropriate or low fuel qual-
ity.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this case: )

• Inappropriate heat value of the spark plug.

DIAGNOSIS

STEP 1. Check the following items.
Carry out the following items, and repair or replace the defec-

tive items.

a. Check the spark plugs.
b. Fuel quality, octane level.

c. Check if the foreign materials (water, kerosene, etc.)

Then confirm that the malfunction symptom is eliminated.

INSPECTION PROCEDURE 21: Dieseling.

.

COMMENT

• Fuel leakage from injectors is suspected, or car-

bon build up.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this case: )

• Fuel leakage from injectors.

DIAGNOSIS

STEP 1. Check the injectors for fuel leakage.
Replace the leaking injector. Then confirm that the malfunction 

symptom is eliminated.

INSPECTION PROCEDURE 22: Too high CO and HC concentration when idling

.

COMMENT

• Abnormal air/fuel ratio is suspected.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this case: )

• Malfunction of air/fuel ratio control system.

• Deteriorated catalyst.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-788

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I

• MB991827: USB Cable

• MB991911: Main Harness B

STEP 1. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC set?

YES : Refer to Diagnostic Trouble Code Chart 

P.13A-26

.

NO :  Go to Step 2.

STEP 2. Check the ignition timing.
Refer to GROUP 11A, On-vehicle Service 

− Ignition Timing 

Check 

P.11A-9

.

Q: Is the ignition timing normal?

YES : Go to Step 3.
NO :  Check that the crankshaft position sensor and timing 

belt cover are in the correct position. Then confirm 
that the malfunction symptom is eliminated.

AK303629AB

MB991911

MB991827

MB991824 

16-PIN