As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RIGHT A/C PACK AUTO FAIL MESSAGE AND RIGHT TEMP 99C DURING TAXI, CREW ALSO REPORTED SMOKE IN THE CABIN. THE AIRCRAFT RETURNED TO GATE WITHOUT INCIDENT. MAINTENANCE FOUND RIGHT ACM DIFFICULT TO ROTATE. MAINTENANCE REMOVED AND REPLACED RIGHT ACM AND PERFORMED CHECKS IAW AMM. THE AIRCRAFT WAS RELEASED FOR SERVICE.