Tire Calibrate As the vehicle moves, the navigation system receives speed pulses from the ECM/PCM. These pulses are converted using a conversion factor to a mph speed that moves the vehicle position (VP) on the map. The navigation system has an internal tuning function that generates and refines this factor based on actual driving. The ‘‘Level'' indicates the status of the tuning. At navigation initialization, it begins at 0, and increases to 10 as the navigation system is used.

- The ‘‘Auto Tuning'' is factory set to ‘‘ON'', and should remain on.
- The ‘‘LEVEL'' indicates the tuning status. If it is less than 10, the unit is still calibrating.
- The ‘‘Tire-Cal. Tuning'' and ‘‘Set'' should not be used. It is for factory use only.