Originally Posted by Mike75

Same thing happened to me last month with my 3.5d. Engine light came on, stayed on for a few days, then went off, and then went on again. Turns out it was a defective air temp sensor, which needed to be shipped from Germany. Took about 2 weeks to replace, as the first sensor they got was broken in transit. Got a 535ix as a loaner, which made things a bit more bearable.