As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED THAT THE LEFT THRUST REVERSER DID NOT DEPLOY UPON LANDING - THE ARM ANNUNCIATOR ILLUMINATED. THE MAINTENANCE STAFF TROUBLESHOT AND DETERMINED THE LEFT CONTROL VALVE WAS AT FAULT. THE CONTROL VALVE WAS REMOVED AND A SERVICEABLE VALVE WAS INSTALLED. OPS CHECKS WERE SATISFACTORY AND THE AIRCRAFT WAS RETURNED TO SERVICE.