As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BZN FLIGHT NR 2328: AFTER ADDING POWER FOR TAXI, FLAP DRIVE CAUTION LIGHT ILLUMINATED AND STAYED ON. DIVERTED FLIGHT BACK TO BZN. AFTER PARKING (AND SHUTDOWN), THE LIGHT CYCLED ON AND OFF SEVERAL TIMES. AIRCRAFT WAS FERRIED TO PDX. MAINTENANCE REMOVED AND REPLACED FLAP POWER UNIT IAW Q400 AMM TASK 27-52-01-000-801 AND 27-52-01-400-801. OPS CHECK GOOD. NO DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.