Hi and welcome to Justanswer.
initially, it possibly that your foot pedal you brought have factory defect you can ask to return the foot pedal to the store you brought it. Or the foot pedal you brought is not compatible to your machine. In case that the foot pedal is compatible as per store said and try a new pedal. There is possibility that your electronic board is faulty. That is not for authorized pfaff dealer fix.
Hope this information will be helpful.
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