What was found
ON TAXI IN, APU WOULD NOT START AND "FAULT" LIGHT ILLUMINATED. ACFT GROUNDED. ACCOMPLISHED APU BITE PROCEDURE IAW 49-60, TASK 801. FOUND MAINTENANCE MESSAGE 49-41011, "NO FLAME SHUTDOWN". ACCOMPLISHED FAULT, ISOLATION TASK 49-40, 802. FAULT 49-41011 WAS DISPLAY AGAIN IN MAINTENANCE MESSAGE. ACCOMPLISHED TEST APU IAW FIM TASK 49-40, TASK 802, STEP 1-G6, ITEM F. REPLACED IGNITER LEAD REF AMM 49-41-52-400-801/ 000-801 AND IGNITER PLUG REF AMM 49-41-51-000-801/ 400-801. OPS CHECK- NO HELP. WHILE T/S FOUND APU LUBE MODULE OIL FILTER INDICATOR POPPED. REPLACED LUBE FILTER ELEMENT REF AMM 49-91-12-000-802/ 400-802 AND FOUND BUTTON ON THE OIL FILTER WON'T RESET. REPLACED IGNITION UNIT IAW AMM 49-41-31-400-801, OPS CHECKS GOOD, APU STARTS AND OPERATES NORMALLY. REPLACED OIL FILTER INDICATOR. REF AMM 49-91-13-400-802. OPS CHECKS GOOD.