Hello, I ask my question first: Does anyone know what is wrong with the car when the CEL keeps coming on? Now the background: I purchased this car about 3.5 months ago with a bit over 16K miles on it. The car is fully loaded (except cold weather package). I love the twin turbo diesel engine, the quick takeoff, the over 400 pounds of power, and all the bells and whistles. The production date is 12/2009. After driving the car for about a month, the DEF warning light came on. I took it to the local BMW dealer and was told when the original dealer performed the first service apparently they never topped off the DEF - I was told it would cost around $185. I complained that this has nothing to do with me and it is not in any way my fault. I called the BMWNA Customer Service and after going back and forth with them was told that I had to pay this dealer and if I had any complains I had to pursue it with the dealer that performed the original maintenance service. After about a month of driving, the yellow CEL came on. I took the car to the local dealer. They ran some tests, didn't find any problems, cleared the fault, drove the car for eight miles, and the light didn't come on again - I hesitantly picked up the car. Three weeks later, the CEL came on again. I took it back to dealer. This time the tech found that the SCR injector bore was completely clogged with white soot. They remove it, cleaned it, installed it back, drove the car for 30 miles and all was OK. Three weeks later, the CEL light came on. I called for an appointment but when I got into the car to drive it down to the dealer, the light was not on anymore so I canceled the appointment. A week later, the CEL came on again, made another appointment, took the car to the dealer and now it has been with them for a few days, they can't find the fault, the SA told me they have called BMW engineers and are now waiting for resolution.