Mitsubishi Montero (2004+). Manual — part 347

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-875

STEP 2. 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 3.

STEP 3. 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 Reference 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 4.
NO : Refer to DTC P0201, P0202, P0203, P0204, P0205,

P0206

− Injector Circuit

P.13A-421

.

STEP 4. Checking by operating the accelerator pedal.
Q: Does the engine stall right after the accelerator pedal is

released?
YES : Refer to On-vehicle Service

− Clean the throttle valve

area

P.13A-421

.

NO : Go to Step 5.

STEP 5. Engine stall reproduction test.
Q: Is it easy to reproduce the engine stall?

YES : Go to Step 6.

AK302970

AB

MB991911

MB991824

MB991827

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-876

NO : Check if the following signals change suddenly by

wiggling the circuit harness and connectors.
a.Crankshaft position sensor signal.
b.Volume airflow sensor signal.
c.Injector drive signal.
d.Primary and secondary ignition signal.
e.Fuel pump drive signal.
f.PCM power supply voltage.

Repair or replace it. Then confirm that the malfunction

symptom is eliminated.

STEP 6. Using scan tool MB991958, check data list.

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-950

.

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).
h. Item 27: Power Steering Pressure Switch.

i. Item 28: A/C Switch.
j. Item 68: EGR valve (stepper motor).

k. Item 79: Throttle position sensor (main).

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

YES : Go to Step 7.
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-877

STEP 7. Using scan tool MB991958, check data list.
(1) Turn the ignition switch to the "ON" position.
(2) Check the following items of the 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).

• Fluctuates between 0 − 0.4 volts 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 9.
NO : Go to Step 8.

STEP 8. 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 9. Check the ignition timing.
Refer to GROUP 11A, On-vehicle Service

− Ignition Timing

Check

P.11A-7

.

Q: Is the ignition timing 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 if the injectors are clogged.
c.Check compression pressure.
d.Check if the foreign materials (water, kerosene,

etc.) got into fuel.

e.Check the EGR valve.

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-878

NO : Check that the crankshaft position sensor and timing

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

INSPECTION PROCEDURE 13: The Engine Stalls when Accelerating (Pass Out).

.

COMMENT

• In case such as the above, the cause is probably

misfiring due to a weak spark, or an inappropriate
air/fuel mixture when the accelerator pedal is
depressed.

.

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

• Vacuum leak.

• Malfunction of the ignition system.

• Malfunction of emission control 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 : Go to Step 2.

AK302970

AB

MB991911

MB991824

MB991827