As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT REVERSER ISOLATION VALVE LIGHT, UPPER EICAS DISPLAYED MOMENTARILY DURING LT REVERSER STOW FOLLOWED BY LATCHED STATUS MESSAGE. SUSPECT PRESSURE SWITCH S858 PCN 481-1961 OR M1987 MODULE PCN 563-3874 NIS DENVER. REPLACED S858, NO HELP. REPLACED RELAYS K26 & K2155 REF MM, ALSO NO HELP.