Diagnostic Aids

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Check for aftermarket equipment installed or personal items that could create a magnetic field that could affect the performance of the compass.
Cycle the ignition before performing the compass magnetic variation adjustment procedure.
Check that the compass module is properly installed in the vehicle. The embossed arrow on the module should be parallel with the centerline of the vehicle.