As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOW MGB OIL PRESSURE WARNING LIGHT ILLUMINATES DURING GROUND IDLE OF THE AC. SWITCH WAS FOUND OUT OF TOLERANCE. SWITCH WAS REPLACED WITH A SERVICEABLE PART WITH NO FURTHER DISCREPANCY NOTED. THIS IS NOT AN UNCOMMON FAULT FOR THIS PART. SUGGEST IMPROVED DESIGN OR BETTER QC FOR INTERNAL PARTS AS PERHAPS ON A THIRD OF THESE SWITCHES FAIL IN SERVICE. (K)