The electrical contacts in the ignition switch may fail and result in erratic instrument panel gauge operation or illumination of the Check Engine Light. A failed ignition switch will require replacement.Google+
Car Problem Reports
GMC Jimmy Electrical Contacts in the Ignition Switch May Fail
GMC Jimmy Problem
Average Mileage: 145,000 mi (100,000 mi - 190,000 mi)
Visitor, 2001 GMC Jimmy
this has happen twice now with only 50k miles.
Changed ignition cause key would not come out and check engine light still on