As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED A SLAT FAIL MESSAGE ON DESCENT. CREW DIVERTED TO IAD FOLLOWED QRH AND LANDED WITH OUT INCIDENT. MAINTENANCE WAS DISPATCHED TO THE AIRCRAFT, TROUBLESHOT AND REPLACED NR 3 AND 4 SLAT SKEW SENSORS, SYSTEM OPERATIONAL CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.