As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING APU BITE 49-60 TASK 801 CURRENT STATUS MESSAGE SHOWS. 49-71147 EGT 1 THERMOCOUPLE SHOWS OPEN CIRCUIT. ACFT GROUNDED. REMOVED AND REPLACED APU WIRING HARNESS IAW AMM 49-11-01-400-802, AND NR 1 EGT THERMOCOUPLE IAW AMM 49-71-21. APU OPERATIONAL TEST AND BITE TEST GOOD, WITH NO CURRENT FAULTS NOTED.