What was found
PDX FLIGHT NR 2311: AFTER PUSH BACK AND PRIOR TO TAXING, WHEN THE PROPS WERE TAKEN OUT OF FEATHER, THE PROP DEICE CAUTION LIGHT ILLUMINATED. AFTER RETURNING TO THE GATE AND PUTTING THE PROPS TO FEATHER, THE LIGHT WENT OUT. MAINTENANCE FOUND NO FAULTS NOTED IN CDS. STARTED AIRCRAFT UNDER SAME CONDITIONS AS DESCRIBED ABOVE AND PROP DEICE CAUTION LIGHT DID NOT ILLUMINATE. NO DEFECTS NOTED. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.