As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENG SPEED CARD MESSAGE DURING TAXI. AC RETUREND TO GATE MAINTENANCE GROUNDED AC AND RANG OUT N2 SPEED SENSOR IAW WDM 73-21-18 AND 77-12-12 FOUND LEFT T41 N2 SPEED SENSOR SHORTED TO GROUND INTERNALLY. REMOVED AND REPLACED SAME IAW B767 AMM 77-12-02. OPS, BITE AND LEAK CHECK GOOD. A/C REMAINS ETOPS 180 AND RETURNED AC TO SERVICE