What was found
ETOPS - BEFORE TOW OPERATIONS, ATTEMPTED TO START APU, "APU AUTO SHUT SHUTDOWN" MESSAGE SHOWN ON ECAM. APU GRANDSCAN CONFIRMS "OIL FILTER SWITCHES" FAULT. CLEAN CONNECTORS P5 & P9 IAW TSM 49-90-00-810-812-A. APU START NOT SUCCESSFUL. REMOVED & INSPECTED PRESSURE SWITCHES IAW AMM 49-91-14. NO DEFECTS NOTED. REINSTALLED- APU START NOT SUCCESSFUL. REMOVED & REPLACED OIL FILTERS IAW AMM 49-91-41. APU START NOT SUCCESSFUL. REMOVED & REPLACED IGNITION EXCITERIAW AMM 49-4-38-400-003-A. REMOVED & REPLACED BOTH OIL FILTER SWITCHES IAW AMM 49-91-14400-002-A. OPS CK GOOD. APU GROUNDSCAN-NO FAULT DETECTED. A/C OK FOR SVC