As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SUP- FLIGHT 397 - AIRCRAFT DIVERTED WHEN THE CREW WAS UNABLE TO PRESSURIZE OVER 1.0. MAINTENANCE INSPECTED THE AIRCRAFT AND REPLACED THE ELECTRONIC CONTROL UNIT AND THE ENVIRONMENTAL CONTROL SYSTEM CONTROLLER. OPERATIONAL CHECKS WERE PERFORMED AND CHECKED GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.