Inspection Procedure 9

COMMENT
- In such cases, the cause is probably that the intake air volume during idle is too great.

TROUBLESHOOTING HINTS
The most likely causes for this case:
- Malfunction of the IAC system.
- Malfunction of the throttle body.

DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)

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 1. 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 2.

If DTC is output, refer to Diagnostic Trouble Code Chart.




STEP 2. Check the idle air control (IAC) motor operation sound.
1. Check that the engine coolant temperature is 20 °C (680 F) or below.

NOTE: Disconnecting the engine coolant temperature sensor connector and connecting the harness side of the connector to another engine coolant temperature sensor that is at 20°C (68°F) or below is also okay

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 3.

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 3. 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 21: Engine Coolant Temperature Sensor.
b. Item 28: A/C Switch.

If the checks above meet the specifications, go to Step 4.

If the checks above do not meet the specifications, repair or replace. Then confirm that the malfunction symptom is eliminated.

STEP 4. Adjust the basic idle speed.
Refer to Basic Idle Speed Adjustment for the adjustment procedure.

Standard value: 700 ± 50 r/min

Check the malfunction symptom, and if not resolved, go to Step 5.
Check the malfunction symptom, and if resolved, the check is completed.

STEP 5. Check the following items.
1. Carry out the following cleaning.
a. Clean the throttle valve area.

After cleaning or adjusting, confirm that the malfunction symptom is eliminated.