What was found
TAKEOFF WARNING HORN ON TAKEOFF ROLL. ALL ITEMS IN PROPER CONFIGURATION MAX AIRSPEED 48 KNOTS WITH LIGHT BRAKING FLAPS AT 15 DEGREES SLOWING TO 10 KNOTS WE GOT A PROP DE-ICE CAUTION. AFTER CLEARING THE RUNWAY AND JOINING THE TAXIWAY THE PROP DE-ICE CAUTION WENT OUT. PERFORMED FUNCTIONAL TEST OF THE TAKEOFF AND WARNING SYS. REF AMM 31-52-00-720-801. SYS OPERATES AS DESCRIBED. FUNCTIONAL TEST OF T/O WARN SYS GOOD. PERFORMED THE FUNCTIONAL TEST OF THE PROP DE-ICE SYS. SYSTEM OPERATES AS DESCRIBED. FUNCTIONAL CHECK GOOD. REF AMM 30-61-00-720-801. PROP DEICE CAUTION DID NOT RETURN. NO FURTHER DEFECTS NOTED. RETURNED TO SERVICE.