As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) PILOTS REPORTED LEFT WING DE-ICER BOOT NOT VERY EFFICIENT WHEN NEEDED. TESTING EVENTUALLY FOUND HOSE P/N 82371-106 FROM FIREWALL TO DUAL REGULATOR LEAKING IF AIRCRAFT ROCKED DURING TEST. THE HOSE WAS HARDENED. THE LOW PRESSURE VALVE WAS NOT OPERATING CORRECTLY IF AIR PRESSURE APPLIED. SUBMITTER SUSPECTS PLUNGER MISSING FROM VALVE.