What was found
OVERSPEED ILLUMINATED DURING APU START ATTEMPT. GROUNDED - YES. PERFORMED APU BITE REF B737-900 FIM 49-60 TASK 801, FAULT HISTORY SHOWS APU OVERSPEED MSG 49-31014 AND MAINT MSG 49-61262 ON CORRESPONDING PREVIOUS STARTS 0,24,136. PERFORMED FIM 49-60 TASK 817, NO DEFECTS FOUND ON APU HARNESS, NO METAL FOUND ON MAG CHIP PLUG, REMOVED AND REPLACED APU SPEED SENSOR REF B737-900 AMM 49-61-21, OPS AND LEAK CHECK GOOD, PERFORMED APU BITE REF FIM 49-60 TASK 801, NO CURRENT FAULTS ON 3 STARTS MADE AFTER SPEED SENSOR REMOVAL AND REPLACEMENT, THIS CLEARS MEL 49-1B.