As the title states I'm throwing a code - "P210B Throttle Actuator B Control Motor Circuit"

Otherwise the car drives fine - maybe a little aggressive downshift from 3-4 that I notice when decelerating but other than that it isn't sluggish, isn't misfiring, isn't out of the ordinary.

I had just replaced the driver’s side airmatic strut about 2 days prior and had the battery unplugged for a few hours while that was happening. Did I reset something or potentially trigger some electrical issue that caused it to freak out?

I haven't seen this anywhere else across the W211 community so it doesn't seem to be a prevalent issue, I just wasn't sure if I should reset the code and see if it comes back or if anyone advised against it.

It’s been a busy 7 months - I've racked up about $7K in maintenance since I've owned the car to include a complete headbolt job / lifters / gaskets, struts, and other random odds and ends (on what was a Mercedes with an immaculate MB Dealer Service History!).

Feeling a little defeated to be honest. Any help would be greatly appreciated.

 

When mine did this there was water in the connector on the front of the engine.

 

I would reset it first and see if it comes back especially since you are saying the car is driving fine. Also might check the TB plug and make sure there is no corrosion in there.

 

Thanks for the advice guys. I went out of town over the 4th of July holiday and figured I would dig into the issue when I got home...

...I got home and started it up after it sat for about a week and the check engine light was gone. Didn't reset it...it just went away?

Scratching my head and I'll probably take a peak at all the wiring around the TB anyway so I don't have the problem re-emerge but its just weird.

 

 

I never figured out what happened. Keep me updated and I’ll do the same if I ever figure it out or if the problem re-emerges.