As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INITIAL CLIMB RECEIVED A DEICE CAUTION LIGHT. FLIGHT WAS HEADING INTO ICING CONDITIONS, RETURNED TO IAD. OHMED OUT THE LOWER DUCT AND UPPER DUCT. ALL READINGS GOOD. MX HAS NOT BEEN ABLE TO GET THE INTAKE HEAT TO FAIL SINCE TAKING AIRCRAFT FROM LINE. MX PERFORMED AIRCRAFT RUNS, SYSTEM OPS CHECKED GOOD. NO DISCREPANCY NOTED.