Key Cannot Be Removed in the Off Lock Position

WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Symptom Diagnostic Procedure Chart - Key Cannot Be Removed In Off Lock Position

Courtesy of GENERAL MOTORS CORP.