2008 Chevrolet HHR Owner's Manual - Page 120
2008 Chevrolet HHR Manual
Page 120 highlights
Compass Calibration If after a few seconds the display does not show a compass direction, (N for North for example), there may be a strong magnetic field interfering with the compass. Such interference may be caused by a magnetic antenna mount, note pad holder, or similar object. If the letter C or CAL appears in the compass window, the compass may need to be reset or calibrated. To calibrate the compass, do the following: 1. Make sure CAL is displayed in the display. If CAL is not displayed, press and hold the compass button until CAL is displayed. 2. While CAL is displayed, drive the vehicle in circles at 5 mph (8 km/h) or less until the display reads a direction. To adjust for compass variance, do the following: 1. Find your current location and variance zone number on the following zone map. Compass Variance Compass variance is the difference between earth's magnetic north and true geographic north. If the mirror is not adjusted for compass variance, the compass could give false readings. The mirror is set in zone eight upon leaving the factory. It will be necessary to adjust the compass to compensate for compass variance if the vehicle is driven outside zone eight. Under certain circumstances, such as a long distance, cross-country trip, it will be necessary to adjust the compass variance. 2-42 2. Press and hold the compass button until a Z and a zone number appear on the display.