As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU CT5ATP EGT HAS HISTORY OF INDICATING LOW AND ERRONEOUS. INDICATION ERRORS ARE SUSPECT. REPLACED APU INLET TEMP SENSOR PER MM 49 61 31 000 801 / MM 49 61 31 400 801. PERF APU BITE PER MM 49 61 00 700 801 NO FAULTS. PRIOR TO SENSOR REPLACEMENT INPUT MONITORING SHOWED APU INLET TEMP TO BE 10 DEGREES HIGHER THAN AMBIENT. AFTER REPLACEMENT INLET TEMP WAS WITHIN LESS THAN 1 DEGREE OF AMBIENT.