new to us ML320

[E150GT]

Hello all,

My girlfriend just bought a 2001 ML320 with 55k on the ticker. It was formerly her parents car,and I noticed that the BAS/ESP and the ETS lights are constatly on as well as intermitant check engine light. Her dad had said something about it just recieving an oil change and the guys forgot to reset the lights. According to the computer it has a 9500 on the little screen with a wrench next to it. I guess its counting down maybe? I was just wondering if what her dad said is true and there is nothing wrong with the car or if maybe the brake light switch is bad like Ive been reading about. Im used to my w126 and know nothing about these newer mercs. By the way what does BAS/ESP mean? As well as ETS? One more quick one. When we go to lock the car, the rear hatch does not lock along with the rest of the doors, but when you open the door the alarm goes off. To lock the rear hatch you have to manually lock it and then shut the door.
Whats up with that? Thanks for any replies in advance.