C Yukon 2WD V8-5.7L VIN R (1999)
Idle Air Control Motor (IAC): Service and Repair
IAC Valve Reset Procedure
With Scan Tool
1. Connect the scan tool to the DLC.
2. Turn ON the ignition leaving the engine OFF.
3. Using the scan tool, select the IAC Reset in Special Functions.
4. Activate the reset function and wait for the IAC counter to stop.
5. Start the engine.
6. Check for proper idle speed.
Without Scan Tool
1. Start the engine for 20 seconds.
2. Turn OFF the ignition for 10 seconds.
3. Start the engine.
4. Check for the proper idle speed.