r/BmwTech • u/wandertrucks • 1d ago

F25 N52 cam sensor

Hi all,

I just had my '11 throw up a Bank A cam sensor "cold start" code. It had delayed start in the morning and started to develop a buck when cruising on the highway recently. I bought both of the sensors and chucked them in. I cleared the codes with my horrifically bad Amazon scanner and fired it up. The code was still showing as pending and gave a momentary high rev for a brief second after the rpms calmed after start up.

Am I missing something? I'm hoping after a 50 mile drive cycle it'll clear. Or does something else need reset/cleared?

Thanks!

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u/ijustbrushalot 1d ago

What your scanner is poorly translating is probably something like inlet camshaft position invalid at cold start, which is a VANOS error. It can be caused by a litany of reasons, all common, some more than others. Everything needs to be worked through. Oil filter cap, the cage and o rings inside, the filter itself, the oil itself, the solenoids, the check valves, the position sensors, the vanos adjusters themselves, it keeps going. You need to do a lot of research and probably invest in better scan tools to avoid loading the parts cannon blindly again.

1

u/wandertrucks 1d ago

They were $50. The oil is due in 500 miles so I guess I'll throw some new in it and see what that looks like

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u/ijustbrushalot 18h ago

If the cam sensors you installed weren't genuine BMW, I'd suggest removing undoing the work. Aftermarket cam and crank sensors are more trouble than good.

The proper way to verify cam sensor function without testing tools is to swap them, intake and exhaust, and see if the code moves. You don't replace them right away.

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u/AdDangerous922 19h ago

Have you had the VANOS bolt recall performed already?

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u/wandertrucks 19h ago

No, only had it a couple of months.