GM Service Manual Online
For 1990-2009 cars only

Compass Calibration

Before calibrating the compass, drive the vehicle to a area that is magnetically clean (free of large metallic objects). Also make sure there is no magnetic objects on the inside or outside of the vehicle close to the mirror.

  1. Start the engine.
  2. Press and hold the COMP switch (on/off switch if equipped with OnStar® controls) until the letter "C" or "Cal" is displayed.
  3. Drive the vehicle in circles at a speed of less than 8 km/h (5 mph) until the letter "C" or "Cal" is replaced by a proper vehicle heading. The calibration procedure is now complete.

Compass Magnetic Variation Adjustment

Magnetic variation adjustments are required when the compass displays a constant error in heading. Variation is the difference between magnetic north and true north due to geographical location.

    World Magnetic Variation Map


    Object Number: 384280  Size: MF
  1. Locate your current geographic location. Refer to the variation zone map.
  2. Turn ON the ignition, with the engine OFF.
  3. Press and hold the COMP switch (on/off switch if equipped with OnStar® controls) until a zone number appears on the compass display.
  4. Depress the COMP switch (on/off switch if equipped with OnStar® controls) to change the compass to the desired zone.
  5. After selecting your zone number, the display will show a compass heading after approximately 5 seconds.