As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE TAXING FOR TAKEOFF THE CREW RECEIVED AN ASYMMETRY WARNING WHEN TAKEOFF FLAPS WERE SELECTED. THE ACFT RETURNED TO THE GATE & MAINTENANCE WAS NOTIFIED. MX PERFORMED A SYS RESET & REMOVED THE FLAP CONTROL UNIT & INSPECTED CONNECTOR PINS. REINSTALLED CONTROL UNIT & PERFORMED A SYS OPERATIONAL TEST WITH NO PROBLEMS FOUND. ACFT WAS RETURNED TO SERVICE.