Hi, try this, with the car in off position press and hold the SERVICE button tan turn on 
ignition to on position( do not start engine),when display reads   se rvice in ?? Miles or 
service! Than release service button and press and hold the odometer reset button 
until service in miles ,days or service is shown,turn ignition off and the reset is 
complete, sometimes this can only be done with audi compatible scan tool,because 
there is no manual reset procedure for this model.