As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OVERSPEED FAIL 3 TIMES IN 15 MINUTES DURING RUN-UP. DURING TROUBLESHOOTING, WHEN MEASURING THE #1 OVERSPEED SENSOR BETWEEN PINS 2 AND 3 IT READ 42 OHMS, WHICH IS OUT OF TOLERANCE. INSTALLED NEW #1 SIDE ENGINE OVERSPEED SENSOR IAW ENGINE MANUAL 77-14-00-900-802-A01. MOC SUCCESSFULLY COMPLETED.