As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON THE FIRST FLIGHT AFTER A TORRENTIAL DOWNPOUR, DURING TAKEOFF FROM A SCENCE CALL THE PILOT NOTICED A LOSS IN OIL PRESSURE INDICATION, THE PILOT IMMEDIATLY PERFORMED A NORMAL LANDING AT THE ORIGIN OF THE FLIGHT WITH OUT INCIDENT. THE MX WAS DISPATCHED AND AFTER INSPECTING THE ACFT, HE FOUND MOISTURE IN THE OIL PRESSURE TRANSMITTER CONNECTOR PLUG, THE MOISTURE WAS REMOVED AND THE ACFT WAS RUN FOR 10 MINUTES WITHOUT ANY FURTHER DEFECTS NOTED.