If it isn't the gas cap, then I am back to my original second choice, a sensor. Could be a vacuum line or something similar, but in any case, it is time to take it to the dealer. I wouldn't reset it, I would leave it latched so there is something for the dealer to look into.

I had an intermittent SES light on my new 535i. I reset it by restarting the engine each time. It came back several more times. Booked it into the dealer. They found a vacuum line that was collapsing with high vacuum. I asked how they located it; there was a TIB on that specific vacuum line. I would never have found it by poking around. I was just glad it wasn't a fuel pump or something major. Sometimes it is just better to let the dealer do their thing. It is under warranty, just take it in.

Just my $0.02

I know most generic OBDII readers can't read the BMW specific codes. I'm wondering if the scanner is not correctly reading the code???

The thing that puzzels me is, if the fault was a constant one why doesn't it come back as soon as I reset it or at least a few minutes after I reset it? It appears to happen right after I filled the gas tank (about a day later or so). A 2007 X3 with a collapsed vacuum line?.....could happen but very odd.

You gotta just take it in for service and drive a loaner!

Just wondering, how do you know that? The one that I have gets updated via downloads from their site. I would think the software is pretty much up to date.

I agree but I also like to learn about BMW's X3 issues. Sometimes the dealers could reset the light and send you on your way based on the work load that they have or can even screw something else up so you keep bringing the car in for service. Unfortunally, I hate to take the car in to the dealers. Last time I took it in they confused it for one of their loaners and even lost my license plate. They got me a new one, but it was a pain in the ass. On top of that the car had a flat tire when I got it. That was another issue. They gave me back the car with a plugged-in tire and I had to take it back for them to fix the flat correctly. They are very unprofessional. They are nice until you buy them the car. But the idiots that I have dealt with at the service dept. at the dealer where I purchased the car are very unprofessional.

:iagree: I know what your saying Skimo100. Dealing with dealers is a painful process :banghead:

I have purchased, previously, a ford explorer 1998, a honda civic 2002, a ford truck F150 2007 all brand new from the dealers. I never took them in for service. I did all the maintenance. Never had any issues. Sold the explorer and the honda last year and got myself the X3. I still have the F150 and have no issues with it. I'm sure they must have some honest guys working at the dealers, but so far I've had no luck with them.

It isn't a constant fault, that is the point.

A collapsed vacuum line is just as possible on a 2007 X3 as it is on a 2008 535 (for which there is a published fix). I am not saying that it is a vacuum line, just that you are very unlikely to be able to diagnose the problem with an aftermarket code reader. It isn't an F150 (not that there is anything wrong with F150s, just that they aren't as complex IMO).

OBDII is a standard all manufacturers use but they are allowed to go outside that with their own codes as well. OBDII was standardized primarily for emissions and it helps smaller shops diagnose most cars without a different code reader for every manufacturer. The generic readers work great for most domestic and non luxury brands. BMW dealers for example use the GT-1 computer to retrieve every code imaginable from their cars. Take active steering for example.... There isn't a standard OBD code relating to that function of the car so BMW has their own which requires their own diagnostic tool to read.

http://www.peakeresearch.com/

This company makes some great diagnostic tools but as usual they are a few years behind because BMW does not legally have to give up their proprietary info for a period of time.