As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT NR 6457 - EWR-IAD - DURING TAXI, AIRCRAFT RETURNED TO GATE WITH NO FURTHER INCIDENTS DUE TO SMOKE COMING FROM AIR CONDITIONING ACCESS VENT. MAINTENANCE INSPECTED AIR CONDITIONER AND FERRIED AIRCRAFT TO LYH. MAINTENANCE REMOVED AND REPLACED FREON MOTOR, OPS CHECK OK. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)