As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ATB DUE TO NO DUCT PRESSURE FROM LEFT ENGINE AND LEFT PACK WOULD NOT COME ON LINE. OPERATED WITH RIGHT ENGINE AND PACK AND DUCT PRESSURE NORMAL. FOUND CONNECTOR ON PRV CONTROLLER LOOSE. TIGHTENED SAME. RAN ENGINE AND PRESSURE CAME UP. A/C RTS.