As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA- NR 1 AHRS SLAVE MODE ON CLIMBOUT OF SEA. HDG FAIL MESSAGE ON NR 1 PFD. SWITCHED EFIS HDG ATT SOURCE TO NR 2. DIVERTED TO PDX. LANDING WEIGHT OF 61,800 LBS. LANDING UNEVENTFUL. REMOVED AND REPLACED THE NR 1 AHRS, OP'S TEST GOOD IAW MTC 6342101. RETURNED TO SERVICE.