Where is the Automatic Transmission Control Module located? What does it do? on 2007 Volkswagen Beetle

this is an automatic transmission. The car has75000 miles on it and the transmission is starting to slipping.

Asked by for the 2007 Volkswagen Beetle
The 'automatic transmission control module' ----CONTROLS THE AUTOMATIC TRANSMISSION , based on inputs from a variety of engine , trans and possibly suspension and body sensors. What kind of service history do you have with the trans?
I just had the transmission fluid changed. The car has not had any problems until now.
Was the fluid change done at the dealer using factory fluid? WORST case scenario-- did you have it 'flushed' , with who knows what brand of fluid( even though it may have been labeled as VW compatible)? If it was aftermarket fluid , I would get it drained & filled at least twice with VW fluid , maybe that might help with the slipping.