according to the manual i read online, if it needs to be calibrated, just drive in circles at 5mph or less until it reads properly. if it needs to be calibrated, a "c" will be displayed.
edit: if you want, i can e-mail you the three pages from the owners manual that talk about the compass.
edit: if you want, i can e-mail you the three pages from the owners manual that talk about the compass.