Inspection Procedure 11
COMMENT- In such cases as the above, the air/fuel mixture may be inappropriate when the engine is cold.
TROUBLESHOOTING HINTS
The most likely causes for this case:
- Malfunction of the AC system.
- Malfunction of the throttle body
- Malfunction of the injector system.
- Malfunction of the ignition system.
DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)
STEP 1. Check it 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 approximately 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. Checking by operating the accelerator pedal.
1. Does the engine stall right after the accelerator pedal is released?
If the engine does not stall, go to Step 4.
If the engine stalls easily, clean the throttle valve area.
Then confirm that the malfunction symptom is eliminated.
STEP 4. Check the engine idling.
If the engine idles properly after being warmed up, go to Step 5.
If the engine does not idle properly after being warmed up, refer to INSPECTION PROCEDURE 8 - Unstable Idle (Rough Idle, Hunting).
STEP 5. 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 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 6.
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 6. 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 7.
If the test items indicate a defect, refer to DTC P0201, P0202, P0203, P0204, P0205, P0206 - Injector Circuit Malfunction.
STEP 7. Using scan tool MB991502, check data list.
1. Check the following items in the data list.
Refer to Data List Reference Table.
a. Item 21: Engine Coolant Temperature Sensor.
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. Check the fuel pressure.
Refer to Fuel Pressure Test.
If correct, go to Step 9.
If incorrect, repair or replace. Then confirm that the malfunction symptom is eliminated.
STEP 9. Check the ignition timing.
Refer to On-vehicle Service - Ignition Timing Check.
If within specifications, go to Step 10.
If not within specifications, check that the crankshaft position sensor and timing bell cover are in the correct position. Repair, then confirm that the malfunction symptom is eliminated.
STEP 10. 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 compression pressure.
c. Check the engine oil viscosity.
Then confirm that the malfunction symptom is eliminated.