As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNWANTED TRANSFER. ACCOMPLISHED MM 28-21-00-720-004-A TEST OF CENTER TANK FUEL PUMP CANISTER CHECK VALVE. LEFT CENTER FUEL PUMP FAILED. NEXT STEP IS PARA 4.A. IN TSM 28-21-810-840-A. REF LOG 1. REPLACED THE CENTER TANK LEFT BOOST PUMP CHECK VALVE, CHECKS NORMAL.