Originally Posted by zero2sixtyZ
Walnut blasting is definitely good. I've heard the best intervals are around 35-40k. It's definitely considered maintenance on these cars because of the direct injection, since fuel doesn't help clean the valves. I've heard the BMS OCC will help with some blowby / carbon, but not all.
2A87 Outlet-Vanos variable cam control test + 3100 boost-pressure control, deactivation
Basically, the VANOS sensors get clogged or dirty, if not fail, and need to be cleaned/replaced. Happens under WOT and it won't allow the turbos to spool until you restart the car.
Been happening more frequently at 77k. It's a quick fix but I haven't had the time yet. I've purchased new bolts and O-rings just in case I can get away with cleaning them.
Here's the DIY:
FWIW my BMS OCC is always bone dry, I guess maybe a light coating on the walls. If anything it's just a pain to get the bottom 1/2 on and off when I do oil changes.
At least cleaning/replacing the vanos looks quick and easy to do!