What was found
AFTER PUSHBACK ON ENGINE START THE APU FAILED BEFORE STATER CUT OUT NO APPARENT ENGINE PARAMETERS EXCEEDED. OBSERVED A CDS FAULT ON CAPTAIN EHSI ATTEMPTED RESTART OF APU WHICH WAS SUCCESSFUL. APU BITE PER FIM 49 60 00 810 801 SHOWED FAULT CODE 49 91007 "LOW OIL PRESS SHUTDOWN" IN FAULT HISTORY. INIT EVAL FOR FAULT 49 91007 PER FIM 49 90 00 810 803 DID NOT CONFIRM FAULT. DUE TO HISTORY RECOMMEND FAULT ISOLATION PER FIM 49 90 00 810 803. REPLACED LOW OIL PRESSURE SWITCH. REF AMM 49 94 22 000 801. OPS CHECK GOOD.