I replaced front wheels bearings in my 2003 e320 as they where making noise wt highway speeds only. They didn't make noise when spinning tire by hand or have any play at all. Upon investigating further and removing hub I found the front outer bearings started to bronze. The inner bearings looked like they had a dry condition and started to scuff. I had two sets of bearings one was national brand other was some Chinese brand ( don't know name). Left side was replaced with national and have no issues at all. After replacing the bearings and started to drive car my abs light came on along with a bas, esp, and break fault. The car had only one actual code stored and current and that was a OEM enhanced code wheel rpm implausible can bus. (Transmission code) Everything was fine with systems before replacement and only happened after. I checked the wheel speed sensor and it was clean and in proper position. I thought maybe I need to use a all system scan tool to delete codes as the regular scan tool isn't capable of deleting codes fully. After thinking about it for a little I decided to get a better set of bearings, my thinking was the bearings are slightly off and hub isn't proper distance from the sensor. After replacing with new bearings and deleting codes everything works fine. It was in deed the bearings. The Chinese ones where ever so  slightly smaller in diameter and was preventing hub from setting properly.  This is just a heads up if you ever run into issues likes these. After actions report, Codes need to be cleared with a bi directional or all systems scan tool as basic scan tool can't clear the whole system. Bearings have to be a name brand along with seals( doesn't have to be OEM but should) Cheap bearings can be a very small amount smaller or bigger causing issues. It's very finicky with the tolerances and the smallest amount of can cause issues. Issues that may happen. Abs system stops working or malfunctions, traction control fault or  malfunctions, wheel speed sensor malfunction causing skipping, bucking and even limp mode. System malfunction of breaks and bas.  This doesn't just apply to Mercedes. This may effect of there German cars or anything else with a similar set up.... Also parts 2 of the stp ceramic oil additive will be done soon. I included 2 other cars in my testing to compare to my results. Parts 2 of testing should be up in a few weeks. I'll include link to old test when posted. I know it's all subjective and doesn't have much meaning since I'm not in a controlled setting. If i can find a climate controled area with a Dyno and alot of testing equipment I'll do part 3.