I'll crack open the RCM and look at re-soldering the air pump relay. The car runs fine I just dont like engine lights, and what if one day that light could mean something else I would know unless I planned on pulling the code one a week.

Thanks for the suggestions, if all else fails I'll shell out a few hundred and buy a new one which is what MB wants anyway. I knew what I was getting into when I bought the thing. Its a German car, if anything goes bad expect to pay big bucks to fix it, I have an audi a6 avant, and an older S Class so its no biggie. I just want to try as many things first, before just saying eff it, new RCM. Thanks.