What was found
DURING 1ST CSS START ATTEMPT, A FAULT LIGHT ILLUMINATED AT FL370. QRH ACCOMPLISHED, TURNED APU OFF, FAULT LIGHT EXTINGUISHED. SUCCESSFUL SECOND START ATTEMPT. ACFT GROUNDED. APU BITE MAINTENANCE HISTORY SHOWS MAINT MSG 49-94226, LOW OIL PRESSURE SWITCH SHOWS OPEN CIRCUIT, SEVERAL PAST OCCURRENCES. R & R THE APU OIL PRESSURE SWITCH AFTER INSPECTION OF THE CONNECTOR, REF AMM 49-94-22-00-801 AND 49-94-22-400-801 AND FIM TASK 49-90 TASK 805. APU BITE FAULT HISTORY SHOWS MAINT MSG 49-41010, NO ACCELERATION SHUTDOWN, OCCURRED 1 TIME. CHECKED CURRENT STATUS , FAULT IS NOT ACTIVE. STARTED APU SEVERAL TIMES WITHOUT FAULT REOCCURRENCE. APU STARTS NORMALLY, REF FIM TASK 49-40, TASK 801.