A4 sitting for 4 months

The battery needs to be hooked up to a maintenance charger for that amount of time, if not it most likely won't start and it could have electronic issues afterwards. Engine oil and filter should be new and the fuel tank should be full and a fuel stabilizer put in the tank to keep moisture from building up in the fuel system. Coolant should be checked for proper protection and PH values.

Storing a car for four months is really nothing that needs special protection; I have a couple cars that often sit that long. Oil degrades and gets contaminated with each warm/cold cycle, so if unrun, there's no big deal. Fuel tank should be full to minimize moisture in the tank. But you will have electrical problems as batteries in modern cars are still electrifying functions while the car's off and they usually can't go more than three weeks without the engine being run. You should have a battery tender, a little charger plugged into an electrical outlet that keeps the charge up so there's plenty of juice for a restart. But most long-term parking doesn't have that, so check with the garage to see if they have emergency service that will give you a jump when you get back. If not, prepare yourself for someone giving you a jumpstart when you return.