What was found
JUST BEFORE TAKEOFF "ENG 1 FIRE DET FAIL" LIGHT CAME ON EICAS 3 SEPARATE TIMES. RETURNED TO GATE. REMOVED FROM SERVICE. INTERROGATED THE CMC AND FOUND FAULTS 26110013UT1 / 26110012UT1 / 26110018UT1. PERFORMED E175 FIM 26-11-00-810-805-A ITEM 1-6B(1)(A) AND FIM 26-11-00-810-806-A ITEM 1-6B(1)(A). EICAS MESSAGE NEVER RETURNED. PERFORMED OPERATIONAL TEST OF THE ENGINE FIRE DETECTION LOOPS IAW E175 AMM 26-11-00-710-802-A. OPS CHECKED GOOD. LET AIRCRAFT SIT AFTER OPS TEST FOR APPROX 10 MINUTES. EICAS MESSAGE NEVER RETURNED. RETURNED TO SERVICE.