As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOI - RECEIVED A LEFT ENGINE DEGRADE CAUTION MESSAGE IN FLIGHT. RETURNED TO THE FIELD. MAINTENANCE FOUND THE LEFT FADEC HAD A INTERNAL FAULT AND REPLACED THE FADEC. AS A PRECAUTION ALSO REPLACED THE K19 AND K21 RELAYS AS A PRECAUTION. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.