Mitsubishi Montero (2002-2004). Manual - part 751

TSB Revision

SYMPTOM PROCEDURES

13Ad-53

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.

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, read the diagnostic 
trouble code (DTC).

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 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 GROUP 13A, Diagnostic Trouble Code Chart 

P.13Ab-22

.

NO :  Refer to GROUP 13A, On-vehicle Service 

− Clean the 

throttle valve area.

ACX01539

16-PIN

MB991502

AC

TSB Revision

SYMPTOM PROCEDURES

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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 Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, read the diagnostic 
trouble code (DTC).

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 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 GROUP 13A, Diagnostic Trouble Code Chart 

P.13Ab-22

.

NO :  Go to Step 2.

STEP 2. Using scan tool MB991502, 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.13Ab-42

.

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 GROUP 13A, DTC P0201, P0202, P0203, 

P0204, P0205, P0206 

− Injector Circuit 

P.13Ac-318

.

ACX01539

16-PIN

MB991502

AC

ACX01539

16-PIN

MB991502

AC

TSB Revision

SYMPTOM PROCEDURES

13Ad-55

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

− Ignition Timing 

Check 

P.11A-6

.

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.

STEP 4. Using scan tool MB991502, check data list.

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 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 GROUP 

13A, Data List Reference Table 

P.13Ab-29

.

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

c. Item 21: Engine Coolant Temperature Sensor.

d. Item 69: Right Bank Heated Oxygen Sensor (rear).
e. Item 39: Right Bank Heated Oxygen Sensor (front).

f. Item 59: Left Bank Heated Oxygen Sensor (rear).

g. 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 MB991502, check data list.
(1) Turn the ignition switch to the "ON" position.
(2) Check the following items of data list. Refer to GROUP 13A, 

Data List Reference Table 

P.13Ab-29

.

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 been warmed.

(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.

ACX01539

16-PIN

MB991502

AC

ACX01539

16-PIN

MB991502

AC

TSB Revision

SYMPTOM PROCEDURES

13Ad-56

STEP 6. Check the fuel pressure.
Refer to GROUP 13A, On-vehicle Service 

− Fuel Pressure Test 

P.13Aa-13

.

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.

STEP 7. Check the fuel pressure.
Refer to GROUP 13A, On-vehicle Service 

− Fuel Pressure Test 

P.13Aa-13

.

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 compression pressure.

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

d. Check the EGR system.
e. Broken air intake hose.

f. Clogged air cleaner.

g. Clogged exhaust system.

Then confirm that the malfunction symptom is 

eliminated.

NO :  Repair or replace. Then confirm that the malfunction 

symptom is eliminated.