I have 06 4.4, and ses came on while I was still running on dealer filled tank. I came back to Shelly BMW, and they accused me not closing fuel cap correctly. They did reset the light, and it was off for a while. at about 700 miles, same thing happened. At 1500 miles, SES came on again. This time this dealer in Ontario kept my car for about 2 days, and they finally found problem. They told me that there is charcoal filter, and sensor behind it. They are not supposed to be soaked with fuel, but mine was. They replaced sensor & charcoal filter. I don't know exact part that was replaced. Sorry. However, this solved problem, and I haven't seen SES.