As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DEN - ON FLIGHT 4191, RETURNED TO GATE. RIGHT PACK FAULT STATUS MESSAGE. MAINTENANCE INTERROGATED MDC, CURRENT FAULT RIGHT PACK COMP TEMP SENSOR CH-B INOP. REMOVED AND REPLACED PACK COMP TEMP SENSOR. RIGHT PACK FAULT CLEARED. AIRCRAFT RETURNED TO SERVICE.