2006 Cayenne Titanium S started losing voltage from not driving..replaced battery under seat...Car was sitting for 2 years...No aux battery in trunk.Car starts runs fine with new battery.. but..Car has blank PCM screen..radio is very muffled sounding and quiet,only can change radio from steering wheel not blank PCM..,cd player in PCM works but like radio very low sound..rear hatch does not open or click..ac /heat blower not working and its blank too..Key batterys were dead..replaced both batt