qwe4565

My key battery died so I couldnt open the door with the remote.. but the car started up fine.. and when I got home I have brand new spare key and that key didnt work either.. also check engine light popped up.. Check engine light was on couple weeks ago and went away by it self and came back on.. what could that be?

taurran

Go to Autozone or Advance Auto Parts. They will pull the codes for free.

03'55AMG

Or try to find somebody local to you that has a STAR setup they can use on your 55. Personally, I don't think the CEL has anything to do with the key fob. And although the batterys may be dead, the ignition provides its own power to the key.

qwe4565

I replaced my key battery and still cant unlock/lock but car starts up fine.. sigh...