As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON APPROXIMATELY AT APPROXIMATELY 5000' AGL AND AFTER SELECTING FLAPS TO 5 DEGREES, BOTH ND'S SHOWED "FMC DISAGREE" WITH A CDU MESSAGE INDICATING THE SAME. AFTER APPROXIMATELY 30 SECS BOTH MESSAGES WENT AWAY. NO QRH PROCEDURE WAS FOLLOWED. ACFT GROUNDED. ACCOMPLISHED FMCS OPS TEST, OPS TEST NORMAL IAW AMM 34-61-00. NO MSG DISPLAYED, NO 90 DAY HISTORY.