As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PREFLIGHT CHECKS BY THE MAINTENANCE TEAM IT WAS DISCOVERED THE LEFT ENGINE OIL FILTER BYPASS ANNUNCIATOR WAS ILLUMINATED. IT WAS DISCOVERED THAT THE LEFT ENGINE OIL FILTER BYPASS PRESSURE SWITCH WAS DEFECTIVE. IT WAS REPLACED WITH A SERVICEABLE UNIT. OPS CHECKS WERE SATISFACTORY AND THE AIRCRAFT WAS RETURNED TO SERVICE