[doeboy6587]

Currently driving a 2008 528i with roughly 165k miles.

My engine light comes on while highway driving and goes off randomly code 2C31 - (thread title is wrong). Been doing this for 3 months now. Occasional trouble starting but just delayed like a half/quarter second longer when pushing the start button. Idle fluctuates 200-300 while in drive but not moving but seems fairly normal and is not erratic IMO.

New: Plugs, Coil Packs, Pre-Cat O2 sensor (cyl 1-3), oil filter housing gasket

This thing is driving me nuts going on and off. Any ideas besides a smoke test and replacing CCV Valve? Thanks!

 

[Jtbgonesailing]

Welcome to the forum!

For just routine maintance, your CCV system, if original, is well past its end of life cycle...

 

[doeboy6587]

Thanks! So on my E60 N52 I need to be searching oil separator right?

 

[twh]

Which one did you replace?

http://www.realoem.com/bmw/enUS/showparts?id=NU53-USA-06-2007-E60N-BMW-528i&diagId=18_0610

 

[doeboy6587]

I replaced #1. I also purchased 4 because it was on sale but haven't installed it yet.

 

[twh]

I'd replace #4 now. I haven't had this problem myself, but some Google searches show that people with 2C31 that doesn't stay gone then changed the post-cat sensor and had success after that. And, since you bought it already, just change it.

 

[doeboy6587]

I'll swap it Friday and keep you posted.

 

[doeboy6587]

Replaced the bank 1 sensor 2 post cat sensor (#4 in diagram) and manually reset the check engine light. 1k miles so far and it hasn't come back on yet.