What was found
BTB - ON TAXI OUT “ENG L SYS FAIL” ALERT ILLUMINATED, ACFT RETURN TO THE GATE // PERFORM DUAL ENG RUN AT IDLE PER FIM 73-22 TASK 806 AND RESET FCC1 AND FCC2, VIA1,VIA2 NO FAULTS OR FAIL NOTED. PERFORMED 2ND ENGINE RUNS #S 1&2 ENG RUN NORMAL. AS A PRECAUTIONARY. MAINTENANCE REPLACED #1 FCC. RTS CHECK GOOD. AIRCRAFT RELEASE FOR SERVICE.