Conditions for Clearing the MIL/DTC
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The theft deterrent control module clears the current status of the DTC when it does not see the Learn Coded Key setting as on. The DTC will still be retrieved as current until the ignition switch is cycled. The DTC will become a history DTC at that time.