As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE AIRCRAFT RETURNED TO THE GATE FOLLOWING A LEFT HAND PROPELLER OVERSPEED TEST FAILURE. MAINTENANCE INSPECTED AND CLEANED THE CANNON PLUG ON THE LEFT HAND PROPELLER OVERSPEED GOVERNOR, IN ACCORDANCE WITH DORNIER MAINTENANCE MANUAL 61-21-01. OPERATIONAL CHECKS WERE COMLETED, AND THE AIRCRAFT WAS RETURNED TO SERVICE.