What was found
EICAS MSG: LT ISL BLD VALVE ON ENG START. CONTACTED DISPATCH TOLD TO RETURN TO BLOCKS. REMOVED AND REPLACED NR 1 ENG ISOLATION VALVE ASSY IAW AMM 36-11-04, OPS CHECKS GOOD.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
EICAS MSG: LT ISL BLD VALVE ON ENG START. CONTACTED DISPATCH TOLD TO RETURN TO BLOCKS. REMOVED AND REPLACED NR 1 ENG ISOLATION VALVE ASSY IAW AMM 36-11-04, OPS CHECKS GOOD.