As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX-RETURNED TO FIELD FOR ENGINE OIL PRESSURE INDICATOR 46 PSI THEN WENT TO 55 PSI AT FLIGHT IDLE AND REMAINED FOR REST OF FLIGHT. NO MATER CAUTION OR MASTER WARNING INDICATIONS. REPLACED #1 ENGINE OIL PRESSURE INDICATOR, NO HELP. OIL PRESSURE DROPPED TO 41 PSI. REPLACED OIL PRESSURE TRANSMITTER. INDICATIONS NORMAL AND STABILIZED. AIRCRAFT RETURNED TO SERVICE.