Odd Problem Looking For Help
 

I tried the search button and it did not work.

Fault Code 235 only

Thanks in advance. I have a 2006 x5 3.0 121K miles, that is giving me, what I believe, is a phantom fault code.
235 - Pre-Cat Bank 1, Fuel Trim
SAV runs great 19-21 MPG no issues at all, other than the SES light.
I only get 235 bank 1, there is no 236 (bank 2) or any other codes to go with it.
I have replaced the following with all new parts in this order:
All 4 o2 sensors
Mass Air Flow
Fuel filter
Fuel pump
Intake boots upper lower
CCV and related hoses (cold weather)
Valve cover gasket
Dipstick o-ring
Oil filter housing gasket
Spark Plugs
Catalytic Converter

No gaskets were leaking, just thought maybe?
The only thing that was odd when I bought this thing the exhaust was cut off at the muffler on bank 1. I took it off and welded it back with no leaks. I also checked the rest of the and there are no leaks. Also replaced all gaskets when I did the cat.

Live data for o2's look great, short and long fuel trim are good.
I did notice that it comes on while I am at and the light will go off on its own after 2 drive cycles and stay off for weeks them come back for 2 drive cycles.

The only thing I am thinking that is left, injector O-rings?
Any help would be appreciated.
Thanks

It's possible that the problem is your DME. There were issues with DME's generating SES lights that pointed to a O2 sensor issue, even when the O2 sensors were replaced with new ones. The fix is to have your DME updated with the latest software that's available to fix the issue. It looks like you've done just about everything you can to remedy the problem, so the DME might be the actual cause.

Thanks for the reply Eric. I also forgot to add that I did a smoke test and found nothing.
I will check when I get a chance to see what version of software I am running.

If I need an update is that something that has to be done by the dealer?
Thanks

Due to cost, I would find a good independent BMW shop to perform the update. A well equipped one should have the tools and software necessary to perform the update.

Now if you're tech savvy, it is possible to perform the upgrade yourself. With a Windows based laptop, the proper USB-OBD2 cable, and the right software you can do it yourself. I won't go into all of that here...you'll need to do some searching on some other forums for that. If you go to E46fanatics.com, there is a DIY coding forum where you can learn all you want to know about updating the DME. I am pretty certain there is information available that will explain how to update the DME software on your own. I've personally re-flashed an MS43 DME that I purchased used off of ebay to replace one in an '01 330i.

Thanks for the replies.
I just wanted to update everyone on this situation.
I have been extremely busy since I posted on here and did not have time to do anything with the X5 and I will say this:
I have not done anything to her and the SES light has been off for 2 months and 4k miles.
Just as it has come, it has gone with no explanation. SO I have no real incite as to what the problem is but have come to the conclusion BMW's are special vehicles they fix themselves. ;)

You should list what scanner you are using to scan the X. The code that you listed is not a P-code so I'm assuming it is not a generic scanner. If the 02 sensors are working as designed per your live data then it must be something else. You said that the long term and short term fuel trim are ok. It would help if you listed the number for each.

Does your scanner do freeze frame? It would help to know what the engine was doing when the error light was set.

I am using a Snap-on Modis.
Yeah sorry I did not post those numbers, but I figure for now I will run'er and see what happens?