As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER LANDING, APU FAILED TO START. APU FAULT ILLUMINATED. GROUNDED - YES. FOUND FAULT 49-41254 ACTIVE BEFORE START SUCCESSFUL. FOUND FAULT 49-41012 REPEAT INSTANCES. CW B737-9 IFIM 49-40-00-810-805 AND 49-40-00-810-818. REMOVED AND REPLACED START CONVERTER UNIT GROUND VERIFICATION CHECK GOOD REF B737-9 AMM 49-41-61-400-801.