RE: 2001 740IL with 60,000 miles
Need help on the the above codes which triggered the Service Engine soon (SES)! I bought this BMW with the SES on and the OBD detected the following:

1) P1158 (Manufacturer controlled fuel and air meter)
2) P0171 (System too lean in bank 1.
3) P0174 (System too learn bank 2
4) P0345 ( Camshaft position sensor.

After the diagnosis, I erase the codes and the drove for few hours then the SES light came on. When i tested P0171 & P0174 were the first to show up. The other codes did show up after two days.

What need to be fixed? Can the failure of one sensor cause the others to fail?
I checked the air intack for leakage and it was okay.

Please help

Someone will have to chime in here but i believe ive heard the CPS (camshaft position sensor) can possibly cause all there errors. But wait until someone else verifies.

Replace the CPS's first, it's the cheapest part [unless you clean the MAF and it works], then troube shoot further if needed. Don't be surprised if the CPS's clear it up!

Replacement Doc, (http://www.bimmerboard.com/forums/posts/63877) always re-check part numbers with your supplier.

The only other thing is maybe the MAF, you could also try cleaning it. Search for directions.

I have the same P0171 code and I believe that replacing the pre-cat sensor from bank 1 will fix this. That is the code that triggered my ses. I have also heard others that say the new o2 sensor fixed this problem. As for the others I'm not sure... Be sure to let us know if you figure it out.

Does the engine struggle to maintain idle when cold....if so, there is a MAF problem. If the car seems to run all right, but the SES light flickers, or comes on full (sometimes going off, but eventually coming back on)....you're looking at classic CPS symptoms.

This is an easy and relatively cheap DIY. Search e38.org for installation procedures. I believe there are 'O' rings which must be replaced as well.

O2 sensors would be my last look. First: CPS. Second: MAF or air leaks. Last: O2 sensors....go from least expensive to most expensive, easiest to most difficult. Sometimes the crank position sensor is the problem, but usually the car will not start if this is the problem.

jake