Compass Calibration and Variance Procedures
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
When the inside rearview mirror with compass is replaced, the compass must be setup utilizing the Compass Calibration and Magnetic Variance (without OnStar Only) .