As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYS - ATB - AT TOP OF CLIMB FUEL TOTALIZER SHOWED A 3400 LB DIFFERENCE THAN FUEL CALCULATED. PERFORMED FQTS BITE TEST, FOUND D1 FAULT. R & R LT MAIN TANK DENSITOMETER IAW AMM 28-41-03-401. OPS CHECK GOOD. OK FOR SERVICE.