According to the owners manual:
"Compass Settings – If Equipped
After pressing the Compass Settings soft-key the following
settings will be available.
• Variance
Compass Variance is the difference between Magnetic
North and Geographic North. To compensate for the
differences the variance should be set for the zone where
the vehicle is driven, per the zone map. Once properly
set, the compass will automatically compensate for the
differences, and provide the most accurate compass
heading. Touch the Calibration soft-key to change this setting. This
compass is self-calibrating, which eliminates the need to
manually reset the compass. When the vehicle is new, the
compass may appear erratic and the EVIC will display
CAL until the compass is calibrated. You may also
calibrate the compass by pressing the ON soft-key and
completing one or more 360-degree turns (in an area free
from large metal or metallic objects) until the CAL
indicator displayed in the EVIC turns off. The compass
will now function normally."
I don't have this in my 8.4n menu and find that the compass isn't very close to accurate. I guess I'm just meant to do 360 degree turns to calibrate. Nothing like the manual telling you to do doughnuts!
Croydon