As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX- NR 2 ENGINE OIL PRESSURE FLUX BETWEEN 50 - 60 PSI IN CRUISE AT 20,000 FEET. NR 2 ENGINE OIL PRESSURE MASTER WARNING OCCASIONALLY FLASHING. ALL OTHER ENGINE INDICATION NORMAL. FLIGHT DIVERTED BACK TO PDX. LANDED WITHOUT INCIDENT. REMOVED AND REPLACED NR 2 ENGINE. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.