[ChaosRogue]

So, I had the check engine idiot light come on in my E46 330 Ci. I got a reader, checked the codes, and got these back: P0171 (System Too Lean); P0174 (System Too Lean); and P0369 (Camshaft Position Sensor "B" Circuit Intermittent). I'm guessing these are all related, and that the easiest thing will be to change Camshaft Position Sensor "B." Has anyone done this before? How difficult is it, and is there anything special I'll need to have/do in order to take care of the job?

I'm guessing this won't be an overly difficult thing, but I have been wrong (so very wrong) before.

Thanks!

[Jazzbass]

P0369 is probably exactly what you think it is.

P0171 and P0174 are Bank 1 and Bank 2 lean conditions. If you're getting both codes at the same time it usually indicates a vacuum leak somewhere in the intake system. How to fix them? Short answer: find the leak and fix it. Long answer: Start reading on page 7 of this thread. Probably a leak in a vacuum hose, intake boot, or CCV tube. E46s are famous for their intake leaks.

[HughA44s]

DO what Jazz said first. After that, is on to the MAF and O-Sensors. You did not mention the mileage but if your up into the 120k range, I would also include that in your thinking. If it were me, I would change the Crankshaft Position Sensor, actually there are two of them and then reset the codes. I like to do this a few times to make sure the BMW OBD is really serious about the codes it is sending or just fxxking with you. The previous comment applies to a car that is basically running ok.

[HughA44s]

Also, resist the temptation to hunt down and replace a single part if you have over 120k on the car. With 3 .e46s, I have come to realize, I do stuff in groups. Let us know what you find.

[SRG]

Agree w/ all of the above.

I've been through most of this w/ our '01 325 wagon. To answer your question on how difficult the cam sensors are to replace - dead easy. The MAF sensor is easy too.

[ChaosRogue]

Actually, I'm around 82K, but they're all still good things to check out. Thanks!