What was found
CREW REPORTED AC WILL NOT PRESSURIZE, OUTFLOW VALVE WILL NOT OPERATE IN ANY MODE. AC RETURNED TO DEPARTURE AND LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT PRESSURIZATION AND RERACKED THE CABIN PRESSURE CONTROLLER AND ACCOMPLISHED A FUNCTIONAL TEST OF THE CABIN PRESSURIZATION SYSTEM IAW MM, SYSTEM TESTED GOOD. THE AC WAS RETURNED TO SERVICE AND DISPATCHED TO THE INTENDED DESTINATION WITHOUT FURTHER INCIDENT. (K)