As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE LNAV AND VNAV DISENGAGED AND WOULD NOT RE-ENGAGE FOR ABOUT ONE MINUTE. NO OTHER INDICATIONS OR FLAGS FMS, IRS AND GPS POSITION WERE ALL NORMAL. GROUNDED - YES. PERFORMED FMC BITE CKED L&R SENSOR INFLIGHT STATUS FAULT AND NO FAULTS NOTED REF B737-900 FIM 34-61 TASK 801. AND ALSO PERFORMED BITE CKED ON ADIRS IFLIGHT FAULTS AND NO FAULTS NOTED REF FIM 34-21 TASK 801.