Inspection Procedure 12
INSPECTION PROCEDURE 12: When The Engine is Hot, It Stalls at Idle (Die Out)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 Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Check if the battery terminal is disconnected.
Q: Has the battery terminal been disconnected lately?
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.
NO: Go to Step 2.
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 connecting 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. Diagnostic Trouble Code Descriptions
NO: Go to Step 3.
STEP 3. Check the idle air control (IAC) motor operation sound.
1. Check that the engine coolant temperature is 20 degrees C (68 degrees 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 degrees C (68 degrees F) or below.
2. Check that the operation sound of the IAC motor can be heard after the ignition is switched to the "ON" position (but without starting the engine).
- An operation sound should be heard.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Did you hear the operation sound?
YES: Go to Step 4
NO: Refer to, DTC P0506 - Idle Control System RPM Lower Than Expected P0506, DTC P0507 - Idle Control System RPM Higher Than Expected. P0507
STEP 4. Using scan tool MB991958, check actuator test items 01, 02, 03, 04: Injector.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting 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 following items in the actuator test. Refer to, Actuator Test Reference Table. Actuator Test Reference Table
a. Items 01, 02, 03, 04: Injector.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?
YES: Go to Step 5.
NO: Refer to, DTC P0201, P0202, P0203, P0204 - Injector Circuit. P0201
STEP 5. Check by operating the accelerator pedal.
Q: Does the engine stall right after the accelerator pedal is released?
YES: Refer to Clean the throttle valve area.
NO: Go to Step 6.
STEP 6. Engine stall reproduction test.
Q: Is it easy to reproduce the engine stall?
YES: Go to Step 7.
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. ECM power supply voltage.
Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 7. 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 connecting 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. Data List Reference Table & Normal Scan Data Values
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 27: Power Steering Pressure Switch.
g. Item 28: A/C Switch.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are they operating properly?
YES: Go to Step 8.
NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 8. Using scan tool MB991958, check actuator test.
1. Turn the ignition switch to the "ON" position.
2. Check the following item in the actuator test. Refer to, Actuator Test Reference Table. Actuator Test Reference Table
a. Item 10: EGR Vacuum Regulator Solenoid Valve.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?
YES: Go to Step 9.
NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 9. Using scan tool MB991958, check data list.
1. Turn the ignition switch to the "ON" position.
2. Check the following item of the data list. Refer to, Data List Reference Table. Data List Reference Table & Normal Scan Data Values
a. Item 11: Heated Oxygen Sensor (front).
- Fluctuates between 0 - 0.4 volt 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 12.
NO: Go to Step 10.
STEP 10. Check the fuel pressure.
Refer to, Fuel Pressure Test. Testing and Inspection
Q: Is the fuel pressure normal?
YES: Go to Step 11.
NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 11. 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 connecting 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 item in the data list. Refer to, Data List Reference Table. Data List Reference Table & Normal Scan Data Values
a. Item 45: Idle Air Control Motor Position.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?
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: Adjusting the basic idle speed. Refer to, On-vehicle Service - Basic Idle Speed Adjustment.
STEP 12. Check the ignition timing.
Refer to On-vehicle Service - Ignition Timing Check in Ignition Timing.
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.
Then confirm that the malfunction symptom is eliminated.
NO: Check that the crankshaft position sensor and timing cover are in the correct position. Then confirm that the malfunction symptom is eliminated.