[dAng! E90]

Hello everyone, I recently bought a used 335i. Today we took a trip to visit family and the "Service Engine Soon" light came on solid. I waited till I got home and put my scan tool on it. I am getting two 0174 codes which is lean on bank 1 and 2. I just need to know if there is something that I need to check or look at. I will take it to the dealer if need be, but I have always been a do it yourself kind of guy.

p.s. It did it while I had cruise control set at 70 mph.

UPDATE: I took it to the dealer two weeks ago and they told me that I needed a new valve cover gasket. They replaced that and checked over the entire car and found no problems. The car spent 4 days at the dealership. Now I have had the car back for two weeks and all was going great until today. The light came back on and I went by the dealership again to find out it is the same code. I have to drop the car off on Tuesday and pick up a loaner car. Now my question, is there something I should check or give them an idea of what to look at? I have owned this car for about a month now and it has spent half the time at the dealership...(I know...Welcome to BMW), but I don't want to have to go through this again. Someone please give me some insight!!!!

Update: BMW just called me and has told me some disturbing news. THEY CAN'T FIND THE ISSUE WITH ME CAR!!! The service adviser has told me the next step would be to pull the intake manifold and clean the valves...a $700 procedure that is not covered under my CPO warranty. He also told me that this procedure might not fix my problem. This issue is getting really old and I would like someone to shed some light on the problem. Tell me what I should do at this point. I just want to enjoy my new to me car, I haven't been able to do that yet.

[enrita]

Are you 100% stock? NO tune, downpipes etc?

If you answer yes than could be bad 02 sensors but i would look in the ecu anyway to make sure there is no tune connected.

[dAng! E90]

Update!!! Please Help!!!

[blisstik]

Do what Enrita says, check on the o2 sensors.

[dAng! E90]

Thanks for the response, but does anyone have another answer. Something else that could cause this SES light?

[dAng! E90]

Ok, thanks. I sure am stressed about this. It's so annoying!!! I ran my scanner on it again yesterday and when the code came on, my scanner was data logging. It showed fuel pressure sky rocket to 74,745psi. I know this is not normal and I don't know if this is just a glitch in the ECU or if pressure shot up. I will tell the dealership about this on Tuesday.

[dAng! E90]

UPDATE!!!

[Jeff@TopGearSolutions]

Carbon build up wouldnt cause a lean burn, if anything you would run rich because you are not getting as much air flow as you normally would.

Faulty fuel bits (injectors or fuel pump) or a misreading/failing o2 sensor would.

A generic scanner wont show you all the codes you need. BMW has what are known as shadow codes that can only be read by BMW or Bavarian technic tool. You may have other codes stored that you cannot see.

[khodo]

I got the same code today on my 335i. I was wondering if this will be covered under the CPO warranty or if I should just fix it myself.

Thanks!