Inspection Procedure 10

Idle Speed Is Low (Improper Idle Speed).

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

TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of the electronic control throttle valve system.
- Malfunction of the throttle body.

DIAGNOSIS

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




STEP 1. Using scan tool MB991502, read the diagnostic trouble code (DTC).

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 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.

NO: Go to Step 2.




STEP 2. Using scan tool MB991502, check data list.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 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.
a. Item 21: Engine Coolant Temperature Sensor.

4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES: Refer to On-vehicle Service - Clean the throttle valve area.

NO: Repair or replace. Then confirm that the malfunction symptom is eliminated.