ML 250 Bluetec - Throttle Actuator Control (issues)
Recently the car started running rough at idle and a few days ago went into limp mode.
Initially scanned with a cheap ebay obd reader and received P2101 - cleared this and was out of limp mode, but the car still idling rough.
Today it went back into limp mode and after a scan I had P2101 and P0638. Was able to clear the codes to get out of limp mode but car still idling rough.
The car feels like it has bad engine mounts at idle i.e. the dash vibrates.
Based on the codes above, I have done some googling but not able to find much for these codes specific to this model; however, the limited information I found is pointing me towards a faulty Throttle Actuator Control unit.
Would any experts care to weigh in?
If so, how do I find the exact part number to order a replacement?
Also, how difficult is it to replace? Seems like it's tucked way under the EGR and intake pipe.
Last edited by rimes; Dec 8, 2025 at 05:21 AM.


