The present invention relates to a method and an apparatus for detecting a failure of a sensor device during operation of the sensor device. A test signal is generated in a first frequency band that is above a signal frequency band of the sensor device and fed into a sensor element of the sensor device. A set of samples is obtained, and a magnitude value is derived from said at least two consecutive samples at the first frequency band. The magnitude value is compared to a magnitude threshold value that defines a minimum for the magnitude value and if the magnitude value is below the magnitude threshold value, it is determined that an error has occurred in the sensor device.