GM Service Manual Online
For 1990-2009 cars only

Compass Calibration and Magnetic Variance Mirror

Compass Calibration

Before calibrating the compass, drive the vehicle to an open area that is magnetically clean or free of large metallic objects such as high tension power lines or large steel buildings. Verify there are no magnetized roof antennas, magnets on or hanging from the mirror, or any other magnetized objects on the inside or outside of the vehicle close to the mirror.

  1. Start the engine.
  2. Important: Before calibrating the compass, make sure the mirror has the correct zone number. Refer to Compass Magnetic Variation Adjustment.

  3. Press and hold the switch for the compass, which may be depicted as COMP, COMPASS, or on/off (w/UE1) depending on the type of mirror on the vehicle, until the letter "C" or "CAL" is displayed.
  4. Drive the vehicle in circles at a speed of less than 8 km/h (5 mph) until the "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

    Object Number: 9020  Size: SH
  1. Locate your current geographic location on the World Magnetic Variation Map.
  2. Turn ON the ignition, with the engine OFF.
  3. Press and hold the switch for the compass, which may be depicted as COMP, COMPASS, or on/off (w/UE1) depending on the type of mirror on the vehicle, until a zone number appears on the compass display.
  4. Depress the switch for the compass to select the desired zone number.
  5. Wait 5 seconds. The display will return to a compass heading. The variance procedure is now complete.
  6. Calibrate the compass. Refer to Compass Calibration mentioned above.

Compass Calibration and Magnetic Variance DIC

Compass Magnetic Variation Adjustment

Compass variance is the difference between the earth's magnetic north and true geographic north. If not adjusted to account for compass variance, the compass in the vehicle could give false readings. Under certain circumstances, such as during a long distance cross-country trip, it will be necessary to compensate for compass variance and reset the zone through the DIC.

World Magnetic Variation Map


Object Number: 384280  Size: MF

    Object Number: 9020  Size: SH
  1. Locate your geographic location. Refer to the variation zone map.
  2. Turn ON the ignition with the engine OFF.
  3. Press the vehicle information button until PRESS [CHECK] TO CHANGE COMPASS ZONE displays on the DIC.
  4. Press the set/reset button to scroll through and select the appropriate variance zone.
  5. Navigate to one of the trip/fuel menu screens to view the direction of the vehicle. This will be shown in the bottom line.

If the compass needs to be calibrated, use the compass calibration procedure below.

Compass Calibration

The compass direction will show CAL or C if it needs to be calibrated. Before calibrating the compass, drive the vehicle to an area that is magnetically clean (free of large metallic objects).

  1. Turn ON the ignition.
  2. Before calibrating the compass, make sure the compass is set to the variance zone in which the vehicle is travelling. See Compass Magnetic Variation Adjustment above.
  3. Press the vehicle information button until the PRESS [CHECK] TO CALIBRATE COMPASS screen is displayed.
  4. Press the set/reset button to start the compass calibration.
  5. The DIC will display CALIBRATING: DRIVE IN CIRCLES. Drive the vehicle in circles at less than 8 km/h (5 mph) to complete the calibration. The DIC will display CALIBRATION COMPLETE when the compass calibration is complete.