You don't have to take it to the dealer to recalibrate the compass. Electronic compasses will recalibrate themselves in normal use, however, if you don't take a lot of turns in the car, you can recalibrate it yourself. Find a large area, such as an empty parking lot. Drive in a figure-8 pattern. Around 3-5 repetitions should recalibrate the compass. Use as tight a turn as possible and maintain a steady speed.