As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 4664, CREW RECEIVED A LEFT PACK AUTO FAIL MESSAGE. MANUAL NOT WORKING. NOTICED A BURNING ODOR IN CABIN. ACFT REMOVED FROM SERVICE. REMOVED AND REPLACED LT PACK BLEED TEMPERATURE SENSOR IAW AMM 36-21-19. NO FIX. REMOVED AND REPLACED THE LEFT AIR CYCLE MACHINE IAW AMM 21-51-08. OPS CHECKED GOOD IAW AMM 21-51-00. ACRT RETURNED TO SERVICE.