As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PIT - FLT 740 - ON CLIMB-OUT FROM PIT, CREW RECEIVED THE EICAS MESSAGE -L ENG FUEL FILT-. FLIGHT RETURNED TO PIT AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE CHANGED THE FUEL FILTER AND IT APPEARED CLEAN. THE DIFFERENTIAL PRESSURE SWITCH WAS THEN CHANGED. (M)