As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LT PACK FLOW CONTROL VALVE (BUT NOT BOTH) OF THE TWO LEFT PACK FLOW CONTROL VALVES ARE NOT IN THE COMMANDED POSITION. STATUS MSG-2124001 LATCHD ER MODE MSG-2124001 LATCHD ER MODE. FOUND CONTROLLER TO BE FAULTY. REPLACED CABIN PRESSURE CONTROLLER. RESET AND OPS GOOD.