As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW HAD SEVERAL INTERMITTENT NR 2 AHRS FAIL INDICATIONS. TROUBLESHOOTING COULD NOT DUPLICATE FAULT. NR 2 AHRS UNIT REPLACED. UNIT CAUSED FAILURE OF HEADING AND REF WITH ASSOCIATED FAILURE OF AUTOPILOT. EVENT CODES INDICATE LOSS OF YAW DAMPENER AND COMPARATOR FAILURE. UNIT WAS REPLACED WITH SATISFACTORY FUNCTIONAL CHECKS. THE ACFT WAS RETURNED TO SERVICE.