As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW RECEIVED A ANVX MAU 1B FAIL MESSAGE ALONG WITH A SPOILER FAULT MESSAGE. CREW RAN QRH AND CONTACTED MAINTENANCE. CREW DECLARED AN EMERGENCY AND LANDED AT DCA WITHOUT INCIDENT. MAINTENANCE RESET MAU 1 AND PERFORMED RETURN TO SERVICE TEST IAW AMM AND OPS CHECKED GOOD.