As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU HAS HISTORY OF MULTIPLE CSS ATTEMPTS WITH FAULT LIGHT PRI: 2ETOPS SIGNIFICANT SYSTEM INSTALLATION TASK AFFECTS APU ON DEMAND IN-FLIGHT START CAPABILITY. UPON COMPLETION, CONTACT MAINTENANCE CONTROL AND REPORT THAT THIS TASK HAS AFFECTED APU IN-FLIGHT START CAPABILITY. GROUNDED - YES. REMOVED AND REPLACED APU LUBE MODULE REF B737-800 AMM 49-91-11. OPS AND LEAK CHECK GOOD.