A device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an active noise reduction system input signal that is related to the vehicle engine operation, and where the active noise reduction system comprises one or more adaptive filters that output noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise. The engine harmonic noise level is estimated from the input signal that is related to the vehicle engine operation, and the output of the transducers is limited based on the estimate of the engine harmonic noise level.