What was found
APU APUC DETECTED FAULT THAT WOULD CAUSE AUTOMATIC SHUTDOWN OF APU IN UNATTENDED MODE OPERATION, OR COMPLETE LOSS OF APUC BUS ACTIVITY (BOTH L AND R 629) FOR 3 SECONDS AFTER THE APU MASTER CONTROL SWITCH HAS BEEN IN THE ON POSITION FOR TEN SECONDS. STATUS CREW COMMENTS: MOMENTARY APU LIMIT EICAS MSG DURING NORMAL SHUTDOWN. MSG-4910270 INACTV PO MODE. -MAT MSG 49-12970. REPLACED LOW OIL PRESSURE SWITCH. RAN APU, NO LEAKS NOTED. NO MSG PRESENT. REMOVED AND REINSTALLED GEN BYPASS SWITCH. NO LEAKS NOTED. SECURED SWITCH. NO LEAKS NOTED.