As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PACK MODE L LEFT PACK AIR CYCLE MACHINE HAS FAILED, OR LEFT ECONOMY COOLING VALVE FAILED OPEN, OR BOTH LEFT CONDENSOR INLET TEMP SENSORS FAILED. LEFT PACK IS OPERATING IN A NON-NORMAL MODE (HEAT EXCHANGER ONLY COOLING MODE). ADVISORY CREW COMMENTS: PACK MODE LEFT. SUSPECT FAULTY CABIN TEMPERATURE CONTROLLER SOFTWARE. REPLACED LT CABIN TEMPERATURE CONTROLLER SOFTWARE IAW 21-61-01 OP CHECKED GOOD. AC OK FOR SERVICE.