As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ASH 7065 IAD-EWR. CREW DECLARED AN EMERGENCY AND RETURNED TO THE FIELD DUE TO A LAV SMOKE WARNING. MX FOUND LAV FAN C/B POPPED, RESET C/B AND FAN OPS NORMAL. MX PERFORMED POWER RUNS WHILE ISOLATING PACKS AND OPERATING LAV FAN. NO SMELL OR VISUAL SMOKE PRESENT.