What was found
(CAN) DURING DECENT IN ICING CONDITIONS AND MODERATE ICE BUILD UP, DEICE PRESSURE CAUTION LIGHT CAME ON, QRH APPLIED, ICING CONDITIONS WAS EXITED AT VMO. BOOT INFLATION WAS VISUAL INSPECTED ON GROUND NR 2 OUTER LT BOOT DID NOT LIGHT UP IN AUTOMATIC MODE AND DID TURN ON DEICE PRESSURE CAUTION LIGHT. IN MANUAL MODE BOOT LIGHT WAS INTERMITTENT WITHOUT ANY CAUTION LIGHT. RETURN FLIGHT CANCELLED. DDV (VALVE) CHANGED AND FERRY FLOWN TO BASE NEXT DAY. THIS IS THE SECOND EVENT IN TWO DAYS WHERE THE APPLIED CB/02/45 HAS TAKEN CARE OF THE DEICE PRESSURE CAUTION LIGHT, WHERE A DDVIN CORRESPONDING BOOT HAS FAILED, AND SUBSEQUENT GROUND CHECK OF SYSTEM HAS DISCOVERED A TECHNICAL MALFUNCTION. DDV WAS REPLACED.