TM 55-1520-240-T 15-6.3 APU STARTING SEQUENCE FAILURE AND ESU P.C. BOARDS FAILURE TABLES 15-6.3 TABLE NO. 15-6.2 APU STARTING SEQUENCE FAILURES APU BITE DECODED STARTING No. SYMPTOM INDICATION BITE TASK SEQUENCE INFORMATION PRE START 1 APU DOES NOT MOTOR ESU Bite indicates NO TEMP DATA 15-2.10 MOTORING 2 APU MOTORS BUT DOES NOT START ESU Bite indicates NO SPEED DATA 15-6.11 3 APU MOTORS BUT DOES NOT START ESU Bite indicates or then FAILURE TO START 15-6.12 4 APU MOTORS BUT DOES NOT START ESU Bite indicates then FAILURE TO START 15-6.13 STARTING 5 APU STARTS BUT SHUTS DOWN ESU Bite indicates OVERSPEED 15-6.14 6 APU STARTS BUT SHUTS DOWN ESU Bite indicates UNDERSPEED 15-6.15 7 APU STARTS BUT SHUTS DOWN OPEN ESU Bite indicates THERMOCOUPLE 15-6.18 HOT START 8 APU STARTS BUT SHUTS DOWN ESU Bite indicates OVERTEMPERATURE 15-6.17 STARTS AND RUNS 9 APU STARTS AND RUNS but SHORTED THERMO. ESU Bite indicates PROBE (warning) 15-6.19 TABLE NO. 15-6.3 ESU PRINTED CIRCUIT BOARD FAILURES - BITE INDICATION TABLE BITE BITE INDICATION INFORMATION PROCESSOR BOARD FAILURE. SENSOR/DATA BOARD FAILURE. PROCESSOR SEQUENCE FAIL Change 8  15-109