As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 526 - KJP-MIA - FLIGHT RETURNED TO KJP, ON CLIMB-OUT OF KJP, AIRCRAFT WOULD NOT PRESSURIZE. OUTFLOW VALVE WOULD NOT CLOSE. REMOVED PRESSURE CONTROLLER, INSPECTED AND CLEANED CONNECTOR, REINSTALLED PRESSURE CONTROLLER. PERFORMED OPERATIONAL TEST PER BOEING MM 21-31-0. SYSTEM OPS CHECK NORMAL. (M)