As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED AN ACS LOW FLOW FAULT. THE MAINTENANCE TEAM TROUBLESHOT AND DETERMINED A FAULTY OVERPRESSURE SWITCH. THE DEFECTIVE SWITCH WAS REMOVED AND A NEW SWITCH WAS INSTALLED. OPS CHECKS WERE SATISFACTORY AND THE AIRCRAFT WAS RETURNED TO SERVICE