No Acceleration on 2000 ML320
 

Last week my kids left the key in the ignition with ignition ON all night. Next morning I had to jump start it because battery was low. It started, but I realised that there is no acceleration. It runs only at idle. I unpluged the battery (assumed to reset the computer), but no luck. I am afraid to bring it to a mercedez dealership, because they will be a big hit on my wallet..Please help ...Thanks

Is the CEL lit?

If so, what is the code?