First time getting "Service Engine Soon" light -- Help --
 

I've had my 2003 4.4i X5 for about 2 years now. With the exception of an alternator replacement I haven't had any running or driving problems. The other evening I saw that my "Service engine soon" light had come on. The vehicle seemed to be running and driving normally and nothing was displayed on the information screen in the cluster.
I scanned the computer the next day and found that it was an error for Engine running too lean at idle, Bank 2.
I cleared the code and went on my way. 2 days later the light is back.

Is anyone familiar with this fault and its usual diagnosis?
The vehicle cracked 100,000mi almost 1 week prior to this light coming on, but as I said earlier everything is operating normally.
Where should I start looking for the culprit(s)?

I suspect the MAF. It's the right mileage and sounds like the right code for it.

Would the MAF cause the code to kick down for only one bank?
and do these fail, or do they just suffer from dirt and use. I was able to see big improvements with my 93' Subaru Legacy Turbo Rally car by cleaning the MAF.

Does anyone know how to reset service engine soon light without obd scanner?

I'm pretty sure you can not reset the light without a scanner. You have to go into the computer and clear the code. The good news is that even if you don't have a scanner your local autoparts store does and most of them will loan it to you, or walk out to your car with you to use it.

It will run OK as it is emissions related. The first and easiest thing to check (you may have done it already) it to check the connectors of the O2 sensors. The engine running lean could be a bunch of fuel related things including Fuel Filter, Fuel pressure regulator, O2 sensors, etc. The engine is just not getting the appropriate amount of gasoline for the amount of Air in the chamber.

I thought so too but I just came from autozone and they told me it was company policy not to reset them. He said maybe unplug battery or it should reset itself after a certain number of cycles. Any truth to this?

Yes, a MAF issue can only affect a single bank. My 2000 4.4i set the Bank 1 Fuel Trim Too Lean code. Replacing the MAF solved the problem. Unfortunately they're not the lowest cost part out there.

As for cleaning if there are MAF specific cleaners. I'm not a big fan of cleaning as more times than not cleaning doesn't help. It won't hurt and only costs a few bucks for the cleaning spray.

Hmm!!! I am really curious on how the single MAF setup can affect only one bank. Also how a faulty MAF can produce a Lean condition instead of a Rich condition.

Check for intake leaks after the MAF, particularly rubber bits that often crack. That's the most common reason for a "too lean" code.