Does the vehicle crank but just won't start?
About two weeks ago on my 2007 X3 (111,000 miles) I had the problem where it would crank but just wouldn't start. I tried jumping it, but that didn't help either. I had it towed to the nearest BMW dealer, 90 miles away. They determined it was a bad fuel pump.
Once it was replaced, I was good.
If I had've known that it was the fuel pump, I could've replaced it myself for around $300.00. But since I had no clue if it was the fuel pump, a sensor, or several other random things, I really didn't have a choice but to tow it in. The final cost for the pump and labor was $820.00.