Mitsubishi Montero (2004+). Manual - part 349

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-883

STEP 5. 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-950

.

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 volts and 0.6 − 

1.0 volts 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 7.
NO :  Go to Step 6.

STEP 6. Check the fuel pressure.
Refer to On-vehicle Service 

− Fuel Pressure Test 

P.13A-995

.

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 it. Then confirm that the malfunction 

symptom is eliminated.

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

− Fuel Pressure Test 

P.13A-995

.

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 it. Then confirm that the malfunction 

symptom is eliminated.

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-884

INSPECTION PROCEDURE 16: Acceleration shock.

.

COMMENT

• There may be an ignition leak accompanying the 

increase in the spark plug demand voltage during 
acceleration or the electronic control throttle 
valve system failed.

.

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

• Malfunction of the ignition system.

• Malfunction of the electronic control throttle valve 

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 the 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.

INSPECTION PROCEDURE 17: Deceleration Shock

.

COMMENT

• There may be a sudden change in air flow 

through the throttle valve, causing the vehicle to 
decelerate rapidly for an instant.

.

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

• Malfunction of the electronic control throttle valve 

system.

• Dirtiness around throttle valve.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-885

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 the DTC set?

YES : Refer to Diagnostic Trouble Code Chart 

P.13A-26

.

NO :  Refer to On-vehicle Service 

− Clean the throttle valve 

area.

INSPECTION PROCEDURE 18: Poor acceleration.

.

COMMENT

• Defective ignition system, abnormal air/fuel ratio, 

the electronic control throttle valve system, poor 
compression pressure, etc. are suspected.

.

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

• Malfunction of the ignition system.

• Malfunction of air/fuel ratio control system.

• Malfunction of the electronic control throttle valve 

system.

• Malfunction of the fuel supply system.

• Poor compression pressure.

• Clogged exhaust system.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-886

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 the DTC set?

YES : Refer to Diagnostic Trouble Code Chart 

P.13A-26

.

NO :  Go to Step 2.

STEP 2. Using scan tool MB991958, check actuator test 
items 01, 02, 03, 04, 05, 06: Injector.
(1) Turn the ignition switch to the "ON" position.
(2) Check following items in the actuator test. Refer to Actuator 

Test Table 

P.13A-966

.

a. Item 01, 02, 03, 04, 05, 06: Injector.

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

YES : Go to Step 3.
NO :  Refer to DTC P0201, P0202, P0203, P0204, P0205, 

P0206 

− Injector Circuit 

P.13A-421

.

STEP 3. Check the ignition timing.
Refer to GROUP 11A, On-vehicle Service 

− Ignition Timing 

Check 

P.11A-7

.

Q: Is the ignition timing normal?

YES : Go to Step 4.
NO :  Check that the crankshaft position sensor and timing 

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

AK302970

AB

MB991911

MB991824

MB991827

AK302970

AB

MB991911

MB991824

MB991827