0804122

Flash: Amplifier (AMP) Diagnostic and System Updates This bulletin involves reprogramming the AMP with the latest available software. Customers may experience the following:Active Noise Cancellation (ANC) drone noise at 950 between 1,000 RPM, during a start up.The AMP may set B221F-00 (Amplifier Internal) erroneously, it does not affect Active Noise Cancelation (ANC) performance. If B221F-00 is a stored fault update the AMP with appropriate software. If fault is active, follow normal DTC diagnostics.