As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 FQIS FAILS SYSTEM TEST AT 401.7 PF AND LEFT MAIN TANK READS 300 LBS EMPTY. GROUNDED-YES. REPLACED TANK UNITS 3, 5, 8, AND 10, PER B737-800 AMM 28-41-21/401. VALUES NOW WITHIN LIMITS PER AMM 28-41-21/501. LEAK CHECKS GOOD. GROUND VERIFICATION SUCCESSFUL.