As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU TREND DATA SHOWS CT5ATP TEMP IS AT OR ABOVE THE THRESHOLD 605 DEGREES GROUNDED - YES. NO RECENT RELATED MTX MESSAGES IN APU HISTORY. NO BLOCKAGE IN AIR INLET OR COMPRESSOR INLET PLENUM. REMOVED INLET TEMP SENSOR & FOUND IT TO BE CORRODED & DIRTY. CLEANED CONNECTOR & REPLACED INLET TEMP SENSOR REF AMM 49-61-31. OPS TESTS GOOD REF FIM 49-40 TASK 825 PARA C & D STEPS 1 & 2.