As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ECU TEST, LEFT OIL PRESSURE LOW ANNUNCIATOR DISPLAYED. OIL TEMP REMAINED IN THE GREEN AND SAME WITH RIGHT ENGINE. LEFT ENGINE OPERATING WITHOUT ANY SIGNS OF DEFECT OR OIL SPILL. INVESTIGATION REVEALED THAT THE CIRPLIP (P/N-DIN_472-28 X 1.2) WAS DISLOGED FROM IT'S MACHINED GROOVE ALLOWING THE OIL PUMP CLOSE OUT PLUG TO FALL OUT CAUSE A COMPLETE LOSS OF OIL PRESSURE.