What was found
OPEN - ETOPS SIGNIFICANT SYS - APU SHUTDOWN WHILE PUSHING BACK. RETURNED TO GATE. T/S IAW FIM49-11-00 FG 110, REM OIL COOLER IAW AMM 49-27-09-004-001 REM OIL COOLER BYPASS VLV IAW AMM 49-27-10-004-001 DISCONNECTED ELEC CONN FROM APU OIL TEMP SENSOR IAW AMM 49-94-01-004-001. INSTALLED OIL COOLER, OIL COOLER BYPASS VLV AND APU OIL TEMP SENSOR IAW AMM 49-27-09 AND 49-94-01 OPS AND LEAK CK GOOD.