As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MOMENTARY 1-2 MINUTE LOSS OF BOTH FMCS CDU DISPLAY AS WELL AS LNAV-VNAV DISENGAGING. NO SPECIFIC QRH FOR THIS PROBLEM, SYSTEMS RETURNED TO NORMAL AFTER 2 MINUTES. NAV DISPLAYS ON BOTH CAPT & F/O FINE DURING PROBLEM. ACFT GROUNDED. PULLED AND RESET NR 1 AND 2 FMCS COMPUTER C/B AND PERFORMED FMCS SYS OPS TEST. ALL TESTS PASS IAW MM 34-61-00.