As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT, LOST ALL VNAV ABILITY AND INFORMATION FROM 8000 TO TOP OF CLIMB. AT LEVEL OFF, TOC, MCDUS IN IN LEGS PAGES FLASHED AND VNAV RETURNED AND FUNCTIONED PROPERLY FOR REMAINDER OF FLIGHT. ACFT GROUNDED. PERFORMED DFCS BITE CHECK AND MOD CONTROL PANEL INSTALLATION TEST REF AMM 22-11-34-740-801. TEST PASSED. NO HISTORY FOR 90 DAYS. OPS CHECKED GOOD.