[jc2078]

Just wanted to post this information in case it helps someone in the future

After changing my valve cover gasket and oil filter housing gasket, which is a common failure on the N54, my car would barely run. Very rough idle and near immediate limp mode with half engine.

After reading the codes with ISTA i had 2a7a and 3100.

The 2a7a code is often referenced as an "unknown" vanos code. the more common vanos codes are 2A82 and 2A87. ISTA refers to 2a7a as an exhaust camshaft sensor error or possibly exhaust vanos solenoid

Anyhow I found that some one else also had this problem after valve cover gasket and oil filter gasket replacement. i replaced both vanos solenoid with aftermarket Gates units with complete resolution. Bought from ECSTuning for 79 dollars each

so to me it appears that part of the gasket in the oil filter may ruin the vanos during replacement

Just a heads up for anyone else with this issue