Is it normal that the check engine light should come on when the diesel exhaust fluid warning appears? A few weeks ago, we got the Diesel Exhaust Fluid countdown procedure warning that the car would not start in xxx miles. I made the appt at BMW for an oil and exhaust fluid change.Just days before the appointment, the check engine light came on. While I assumed it was related to the exhaust fluid issue, I called BMW and asked that they check out the the check engine light. I was told that that would add another hours labor ($142) to check the code. I asked that they not check the code until after the service was complete as that service might cause the engine light to go out. I was told it did not go out, that they did the code diagnosis and the exhaust fluid tank was the problem, repair would be $1100.00. I said I'd have to think about that. When I picked it up I was told that the check engine light was out at the moment but would likely come back on. It hasn't lit back up after several hundred miles, all seems well. Should they have known that the check engine light was related to the diesel exhaust fluid? Might seasoned diagnosticians not have done the check engine code diagnosis?