As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CABIN PRESSURIZATION CONTROLLER FAILED. AIRCRAFT DESCENDED EARLY TO FL 240. WHEN TROUBLESHOOTING TO DETERMINE THE CAUSE OF THE CABIN PRESSURIZATION CONTROLLER FAILURE, BOTH AUTO PRESSURE CONTROLLERS WERE BITE TESTED AND THE OUTFLOW VALVE WAS OPERATED. OPERATIONS CHECK NORMAL. NO FAULTS FOUND. THERE HAVE BEEN NO FURTHER DISCREPANCIES INDICATED.