As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DEPARTURE, NR 1 PNEUMATIC TEMPERATURE LIGHT ILLUMINATED. FOLLOWED COCKPIT OPERATING MANUAL PROCEDURE. UNABLE TO DEPRESSURIZE DUCT. REDUCED THROTTLE AND BROUGHT TEMPERATURE DOWN. FLIGHT RETURNED TO MSP AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED PNEUMATIC PRESSURE REGULATOR VALVE, OPERATIONAL CHECK OK.