2008 335i Check Engine Running Rough

[knaber0902]

I am hoping to get help diagnosing a current problem I am having with my 2008 335i from someone who may have had a similar issue. I upgraded to this car a few months ago from a e46 323ci so I still have a lot to learn on the e90s. Tonight I was pulling out from a stop sign and the half engine yellow light came on, shortly followed by the upper yellow "check engine soon" light. The radiator fan then started blowing at full speed, but I never smelled coolant. I raised the hood with it running and didn't hear anything abnormal besides the fan. I was a couple miles from home, so I limped it back to get my OBD2 reader. The whole way it was jerking and surging, especially below 2500 RPM. The code reader found 3 codes, but just displayed them as "N/A". I will try to borrow a better reader from a friend, but in the mean time trying to find some answers. I erased the codes and restarted the car and both lights immediately came back on. Any suggestions/advice would be greatly appreciated!

[gmu525i]

That's a crappy end to your drive! Sounds a bit like a massive vacuum leak, but that probably wouldn't have come on that suddenly...

Three questions:
- What kind of reader do you have? Not all OBD-2 readers are the same and I suspect the e90s are CANBUS cars.
- Does your reader show the numerical fault codes with a description of "N/A", or really nothing at all?
- Were the codes marked as Pending/Confirmed/Permanent?

Depending on where you are and if you don't get it figured out any other way, I have a CANBUS reader you could use.

Stephen

[jhm5]

As mentioned above, you need a code reader that sees BMW codes, not just generic OBD codes. Was your oil temp high? Do you have adequate coolant? Could be a lot of things, including vanos sensors, coils, high pressure fuel pump. I would not limp that car along if it's jerking and surging. Limp mode usually just dramatically limits power, but it should not jerk and surge.

Good luck.

John