kingsalami

Long time lurker with just a few posts...I hope I'm posting in the correct forum here.
I used Carista to pull a couple fault codes on my wife's 2012 Q5 3.2. It showed a bad side marker bulb and this fault for the engine controller:
P2857 Clutch A Pressure Engagement Performance

I reset the code twice, but this one keeps popping back up. I Googled the code exhaustively, but wasn't able to find any information on it.

I initially thought it was a transmission fault, so I engaged Sport mode and hammered on it a few times to see how it operated. No indications of any problems with the engine or tranny. Everything seemed to work just fine. Anybody got any ideas or hear of this before?

Thanks!

Don Keener

Certainly sounds like a transmission problem. If you have a friend with a VCDS Id suggest pulling the logs with it. Much likely more information there.

Redd

I would guess that means the ECU is seeing an incorrect hydraulic fluid pressure on the "A" clutch. Sort of like a low tire pressure warning: It will still keep working, but it is outside of normal range and failing. (Or, as usual, a sensor might be defective.)

Even on an old-fashioned manual clutch, it will keep working "just fine" for a long time, but when you see how the new replacement bites...big difference between "just fine" and "correct".