2006 Toyota Avalon XLS

This car was my father in-law that recently pass away and we don't have use for it. Car runs great since is a Toyota and the last service the car got at the end of last year they did new breaks, sway bar links (is a part on the suspension of the car), replaced the oil and took it to get professionally detailed and sanitized as courtesy to the new owner. Since the car was just seating on the garage (about 6 months or so) when we drove it to get it detailed the check engine light came on and