Inspection Procedure 12
COMMENT- In cases such as the above, the ignition system, air/fuel mixture, idle air control motor or compression pressure may be faulty. In addition, if the engine suddenly stalls, the cause may also be a loose connector.
TROUBLESHOOTING HINTS
The most likely causes for this case:
- Malfunction of the ignition system.
- Malfunction of air/fuel ratio control system.
- Malfunction of the IAC system.
- Vacuum leak.
- Improper connector contact.
DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)
STEP 1. Check if the battery terminal is disconnected
Has the battery terminal been disconnected lately?
If no, go to Step 2.
If yes, start the engine and let it run at idle for approximate 10 minutes after engine warm-up. Then, if a malfunction occurs, go to Step 2.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
STEP 2. Using scan tool MB991502, read the diagnostic trouble code (DTC).
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Read the DTC.
If DTC is not output, go to Step 3.
If DTC is output, refer to Diagnostic Trouble Code Chart.
STEP 3. Check the idle air control (IAC) motor operation sound.
1. Check that the engine coolant temperature is 20°C (68°F) or below.
NOTE: If necessary, you can disconnect the engine coolant temperature sensor connector and connect the harness side of the connector to another engine coolant temperature sensor that is at 20°C (68°F) or below.
2. Check that the operation sound of the IAC motor can be heard after the ignition is switched to "ON" position (but without starting the engine).
- An operation sound should be heard.
If a sound is heard, go to Step 4.
If no sound is heard, refer to DTC P0505 - Idle Control System Malfunction.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
STEP 4. Using scan tool MB991502, check actuator test items 01, 02, 03, 04, 05, 06: Injector.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position
3. Check following items in the actuator test. Refer to Actuator Test Reference Table.
a. Item 01, 02, 03, 04, 05, 06: Injector.
If the test items do not indicate a defect, go to Step 5.
If the test items indicate a defect, refer to DTC P0201, P0202, P0203, P0204, P0205, P0206- Injector Circuit Malfunction.
STEP 5. Checking by operating the accelerator pedal
1. Does the engine stall right after the accelerator pedal is released?
If no, go to Step 6.
If yes, clean the throttle valve area.
Then confirm that the malfunction symptom is eliminated.
STEP 6. Engine stall reproduction test.
If the engine stall is reproduced easily, go to Step 7.
If the engine stall is not reproduced, check if the following signals change suddenly by wigging the circuit harness and connectors.
- Crankshaft position sensor signal.
- Volume air flow sensor signal.
- Injector drive signal.
- Primary and secondary ignition signal.
- Fuel pump drive signal.
- ECM power supply voltage.
- PCM power supply voltage.
If the engine stall is reproduced by wiggling the harness or connector, inspect that circuit harness and connectors. Then confirm that the malfunction system is eliminated.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
STEP 7. Using scan tool MB991502, check data list and actuator test.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Check the following items in the data list.
Refer to Data List Reference Table.
a. Item 13: Intake Air Temperature Sensor.
b. Item 25: Barometric Pressure Sensor.
c. Item 21: Engine Coolant Temperature Sensor.
d. Item 59: Heated Oxygen Sensor (rear)
e. Item 11: Heated Oxygen Sensor (front)
f. Item 69: Left Bank Heated Oxygen Sensor (rear)
g. Item 39: Left Bank Heated Oxygen Sensor (front)
h. Item 27: Power Steering Pressure Switch. Item 28: A/C Switch.
j. Item 29: Park/neutral Position Switch
4. Check the following items in the actuator test. Refer to Actuator Test Reference Table.
a. Item 10: EGR Solenoid.
If the checks above meet the specifications, go to Step 8. If the checks above do not meet the specifications, repair or replace. Then confirm that the malfunction symptom is eliminated.
STEP 8. Using scan tool MB991502, check data list.
1. Check the following items of the data list. Refer to Data List Reference Table.
a. Item 11: Heated Oxygen Sensor (front)
b. Item 39: Left Bank Heated Oxygen Sensor (front)
- Fluctuates between 0 - 0.4 volts and 0.6 - 1.0 volts while idling after the engine has been warmed.
If incorrect, go to Step 9.
If correct, go to Step 12.
STEP 9. Check the fuel pressure.
Refer to Fuel Pressure Test.
If correct go to Step 10.
If incorrect, repair or replace. Then confirm that the malfunction symptom is eliminated.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
STEP 10. Using scan tool MB991502, check data list.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Check the following items in the data list.
Refer to Data List Reference Table.
a. Item 45: Idle Air Control Motor Position.
If the checks above meet the specifications, go to Step 11. If the checks above do not meet the specifications, adjust the basic idle speed. Refer to Basic Idle Speed Adjustment. Then confirm that the malfunction symptom is eliminated.
STEP 11. Check the following items.
1. 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.
STEP 12. Check the ignition timing.
Refer to On-vehicle Service - Ignition Timing Check.
If within specifications, go to Step 13.
If not within specifications, check that the crankshaft position sensor and timing belt cover are in the correct position. Then confirm that the malfunction symptom is eliminated.
STEP 13. Check the following items.
1. 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.
Then confirm that the malfunction symptom is eliminated.