What was found
APU FAULT LIGHT ILLUMINATED DURING START ATTEMPT. LIGHT EXTINGUISHED ONE MINUTE AFTER SWITCH TURNED OFF. NO SUBSEQUENT START ATTEMPTED. ACFT GROUNDED. PERFORMED APU BITE, FOUND MESSAGE 49-41012, NO ROTATION SHUTDOWN. INSPECTED MAGNETIC CHIP DETECTOR, IAW AMM 49-91-81. NO DEFECTS NOTED AT THIS TIME. PERFORMED SECOND BITE CHECK OF APU, MESSAGE 49-41012 STILL EXISTS IN FAULT AFTER PERFORMING SECOND SUCCESSFUL GROUND START. INFLIGHT APU START ATTEMPT WAS SUCCESSFUL.