As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RIGHT MAIN TANK FUEL QTY & TOTAL WENT BLANK ONCE AIRBORNE. CAME BACK ONCE WE LANDED. GROUNDED - YES. AIR TURNBACK. REMOVED AND REPLACED FUEL TANK UNITS 7, 8, 3, 10 REF B737-900 AMM 28-41-21/401. #2 FQIS SYSTEM TEST GOOD AT 397.2 PICO FARADS REF AMM 28-41-00-730-801.