Do the usual:

1. Make sure you have the latest version software (to fix any bugs). Current version is 4-1/100 (displayed as 4-1/00)

2. Check the wheel pulse is working properly (in Service Mode)

3. Check the satellite signal is normal strength (S/N 6-12 ) and PDOP is normal (<3.0)

4. Make sure you've done a calibration drive so the wheel pulses match your car. Drive on a motorway for about 10-15min. Calibration can take 1-2 weeks to be spot on.