As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
L TRIM AIR VALVE WILL NOT OPEN. TRIM AIR L 1) OVERHEAT IN ZONE SUPPLY DUCT, OR 2) LEFT TRIM PRSOV FAILED CLOSED, OR 3) LEFT TRIM AIR SWITCH COMMANDED OFF. ADVISORY MSG-2124201 INACTV ER MODE. L TRIM AIR VALVE WILL NOT OPEN. CABIN TEMP CONTROL REQUIRES SO MUCH ATTENTION THAT IT IS UNSAFE. REPLACED LEFT TRIM AIR PRSOV AND CKS GOOD.