As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
#1 OIL PRESSURE RAPIDLY FLUCTUATING FREQUENTLY HITTING 72 PSI AND TURNING YELLOW. RETURNED TO FIELD. LANDING UNEVENTFUL. REMOVED FROM SERVICE. INSPECTED AND CLEANED #1 ENGINE OIL PRESSURE TRANSDUCER CONNECTOR, GROUND RAN ENGINE, NO FLUCTUATION OF INDICATION NOTED PER Q400 AMM 71-00-00-780-801. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.