Dodge 2005 Durango Owner's Manual page 141

UNDERSTANDING THE FEATURES OF YOUR VEHICLE 141
symbol is displayed complete one 360 degree turn in an
area free from large metal objects or power lines. The
CAL symbol will turn off and the compass will function
normally.
Compass Variance is the difference between magnetic
3
north and geographic north. In some areas of the country,
the difference between magnetic and geographic north is
great enough to cause the compass to give false readings.
If this occurs, the compass variance must be set according
to the Compass Variance Map.