Setting Magnetic Zone Variance: Ct:

WARNING: This page is about a different car, the 2003 Dodge Grand Caravan, 2003 Dodge Caravan, 2003 Chrysler Voyager, and 2003 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.

The ignition switch must be in the On position and the C/T display must not be blank.
Press and hold the C/T and US/M buttons (approximately 5 seconds) until VARIANCE = XX is displayed. The C/T will display the variance zone stored in memory and the word VARIANCE.
Use the US/M button to select the proper variance zone number, 1 through 15.
After selecting the proper zone number, momentarily press and release the C/T button. The variance zone is then stored in the memory and the C/T returns to normal operation.