As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB THE AIRCREW GOT A WING ANTI-ICE FAIL MESSAGE. AIRCRAFT RETURNED TO IAD. MAINTENANCE INSPECTED, TROUBLESHOT THE SYSTEMS, AND HAD AIRCRAFT FLY A TEST FLIGHT DURING WHICH EQUIPMENT WAS CONNECTED TO TEST THE ANTI-ICE SYSTEMS IN FLIGHT. MAINTENANCE REMOVED AND REPLACED THE LOW PRESSURE SWITCH. SYSTEM CHECKED GOOD.