The Initial Diagnosis

The next business day, I received a call from the BMW service department.  The caller said "your car is throwing a vanos failure code."  I asked what a "vanos" was, and the caller said "it's the system that controls the opening and closing of your valves."  The caller said they wanted to do some more diagnostics and they would call me back.  The next day I received a call from the service manager (he has since moved on to another dealer).  The first thing I noticed was a panicked tone in his voice.  At that point, I began to suspect something serious was awry.  He basically told me that the "vanos" needed to be replaced and that it cost in the neighborhood of $5000.00 and if BMW would not pay for it, he could not do anything to help me further.  I said, "why would BMW not pay for it?".  He replied, "because you have a supercharger installed on the car -- you see, BMW has a policy of "voiding the warranty" when customers install non-BMW parts on their vehicle."  I told him that I was familiar with the Magnusson Moss Warranty Act and knew that it prohibited such "tying" practices (i.e. tying warranty coverage to the use of manufacturer parts).  I also told him that under Magnusson Moss, BMW could not "void the warranty" and furthermore had the burden to prove that the aftermarket parts caused the failure of the "vanos" before denying a warranty claim.  I told him, the more plausible cause would have been his own technician's negligence in adjusting the valves, which are of course connected to and right next to the "vanos."  When I said that, I realized the cause for the panic in his voice.  He was worried that his dealer would be liable for the repair.  What I did not realize is that there was even more reason for his panic.