Hello and thanks for reading, this is my first of many posts here hopefully. I’ve researched a bit and couldn’t find what I needed so here I go.

So I bought a 2009 528i with 214k miles for $3500... it has impeccable service records and was a 2 owner car before me, leased then locally owned and dealer serviced religiously. Risky, I know, but what the hell. I drove it for about 1k miles and it ran beautifully.. felt like a new ride still.. and then it went into limp mode... ugh.

I purchased a Foxwell nt510 to diagnose what’s the problem. Under the engine I get a code of 2A94, crankshaft sensor, signal. Under transmission it comes up
51 A6 EGS Engine signal.

I can clear the codes and it runs perfect again. Shut it down and it reverts back. Bought a new Crankshaft Position Sensor, o-ring, and bolt... swapped ‘em out and to my dismay nothing changed.

Not sure where to go from here.. maybe the harness has a bad wire in it.. In hindsight, I didn’t clean out the connector before plugging the new one in... maybe corrosion in there? Fuse?

Other than a long start and limp mode, after I clear the codes it runs smoothly. Doesn’t idle so bad even before clearing the codes. Anyone have a similar experience?

Skol!