Bought this car few weeks ago, and it ran perfect. The only problem was the key fob wouldn't unlock/lock the doors. The key just had to do lock/unlock which was fine for me. Then my mom thought it was a good idea to to try to replace the batteries in the key fob.. then the car just gave me a start error every time tried to start with every lifht lighting up on dash. I ordered a new key fob and tried putting the key into that, with no avail. I've tried reprogramming, checked the battery, etc. I don't live anywhere close to a Mercedes dealership, so any help would be much appreciated.