Mitsubishi Montero Sport (2004+). Manual - part 340

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-773

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 warmed-up.

(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-774

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.

c. Check compression pressure.

d. Check the fuel filter or fuel line for clogging.

Then confirm that the malfunction symptom is 

eliminated.

NO :  Repair or replace. Then confirm that the malfunction 

symptom is eliminated.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-775

INSPECTION PROCEDURE 16: Acceleration shock.

.

COMMENT

• There may be an ignition leak accompanying the 

increase in the spark plug demand voltage during 
acceleration.

.

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

• Malfunction of the ignition system.

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 :  Check the following items, and repair or replace the 

defective items.

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

cables.

b. Check for occurrence of ignition leak.

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-776

INSPECTION PROCEDURE 17: Deceleration Shock

.

COMMENT

• There may be a sudden change in air flow 

through the IAC, causing the vehicle to deceler-
ate rapidly for an instant.

.

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

• Malfunction of the IAC system.

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.

AK303629AB

MB991911

MB991827

MB991824 

16-PIN