The simplest and most common reason for the BAS/ESP lights to come on is a battery voltage failure. This causes the steering angle sensor to get viewed without it being properly adapted. Because that happened the instant the car was turned on with a unadapted sensor the fault is set. the first time the steering wheel goes lock to lock the steering angle gets adapted but the code that was set stays, unless you disconnect the battery. But of course if you disconnect the battery you start the process over.

I'm not sure why sometimes you can disconnect the battery without this problem but it is real common to set the code just changing the battery.

Lots of other posibilities, and AZ ain't gonna have a clue about any MB codes they can't set with a generic OBDII scanner, which won't touch anything but the motor. There are atleast 7 other controllers on an ML that AZ can't do squat about. You might want to try a real technician, but if you have no better attitude than Ethan you are likely to get screwed.

I sure have no interest in dealing with anyone that don't trust me. They can get THEIR car worked on somewhere else. Ya see I can spot jerks just as easily as he finds crooked technicians. Just why would I fix a jerks car, when there are real customers to deal with. Real technicians don't go begging for work, mind ya.

I'd go somewhere free and see if they can help you with Ethan's attitude. AZ is a good place to start.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician