Re calibrating Sat Nav

[Alastairm]

Chaps

Can these things be recalibrated? Reason being is that mine has started to play up-it shows the right street etc on the map section but if i want it to guide me to a petrol station for example it does not know where it is going or sends me somewhere else where there is no petrol station!!
Can these things be recalibrated? If so is it a DIY job or a dealer job?

Thanks

[john_p]

Which model + year?

[Alastairm]

2001 M5. Running with 2004 disc if that helps.