What was found
ON TAKEOFF ROTATION, HAD INDICATED GND MODE, FPV WITH LEGS, & BRAKING ACTION INDICATOR. GEAR RETRACTED NORMALLY BUT WITH FLAP RETRACTION RECEIVED A TAKEOFF WARNING HORN. FOLLOWED QRH PROCEDURE, GROUND SENSOR FAILURE, WHICH DIRECTED RTB. CYCLED FLAPS TO VERIFY NO FAULTS. ALSO PERFORMED RTS ON EPCU AND VIA`S NO FAULTS NOTED.