Inspection Procedure 17

COMMENT
- There may be a sudden change in air flow through the IAC, causing the vehicle to decelerate rapidly for an instant.

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

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

CAUTION: To prevent damage to the scan tool, turn the ignition switch "OFF" before connecting or disconnecting the scan tool.




STEP 1. Using scan tool MB991502, read the diagnostic trouble code (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 (68° 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 "ON" (but without starting the engine).
- An operation sound should heard.

If a sound is heard, go to Step 3.

If no sound is heard, refer to DTC P0505 - Idle Control System Malfunction <3.0L Engine> or refer to DTC P0505 - Idle Control System Malfunction <3.5L Engine>.

CAUTION: To prevent damage to the scan tool, turn the ignition switch "OFF" before connecting or disconnecting the scan tool.




STEP 3. Using scan tool MB991502, check data list.
1. Check the following items in the data list.
Refer to Data List Reference Table.

a. Item 14: Throttle Position Sensor.
b. Item 26: Closed Throttle Position Switch <3.0L Engine>.

If the checks above do not meet the specifications, repair or replace.

If the checks above meet the specifications, clean the throttle valve area.

Then replacing or cleaning, confirm that the malfunction symptom is eliminated.