As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, RECEIVED RT OIL PRESSURE WARNING MESSAGE ACCOMPANIED WITH FLUCTUATIONS OF 25-36 PSI C/W QRH RETURNED TO DEPARTURE. ACFT RETURNED TO DEPARTURE AFTER TAKE OFF, EMERGENCY DECLARED. R & R RT ENGINE OIL PRESSURE SWITCH O-RING IAW AMM-79-31-03, LEAK CHECK GOOD.