As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAW CREW VERBAL, CREW COULD NOT PRESSURIZE AND RETURNED TO DEPARTURE. PRESSURIZED OK OFF APU. PACK/ZONE TEMP CONTROLLER BITE SHOWS SRADA EXHAUST FAULT. R & R RAM AIR EXHAUST ACTUATOR. BITE TEST PASSES AND OPS CHECKED RT PACK NORMAL. REF AMM 21-51-27. EVALUATION FLIGHT SET UP DUE HISTORY OF PACK FAULTS.