There should be no DTCs displayed. The idle air control
system has been checked.
- Set the parking brake.
 
- Block the drive wheels.
 
- Connect a scan tool to the DLC connector with the tool in the
open mode.
 
- Start the engine.
 
- Bring the engine to the normal operating temperature.
 
- Check for the correct state of PRNDL (R-D-L)switch position on
the scan tool.
 
- Check the specifications table for controlled idle speed and IAC
valve pintle position (counts). Refer to Fuel System (Overview)
.
 
- If within specifications, the idle speed is being correctly controlled
by the control module.
 
- If not within specifications, refer to Driveability Symptoms.