What was found
PHX - FOLLOWING GEAR UP SELECTION, GEAR DISAGREE WARNING CAME ON ACCOMPANIED BY PROX SYSTEM 1 FAULT STATUS MESSAGE. MAINTENANCE INTERROGATED THE MAINTENANCE DIAGNOSTICS COMPUTER AND THERE WERE NO CURRENT FAULTS. THE MAIN LANDING GEAR SELECTOR VALVE AND PROX SENSORS WERE CHECKED WITH NO DEFECTS NOTED. THE LANDING GEAR WAS CYCLED SEVERAL TIMES WITH NO DEFECTS NOTED. THE PSEU WAS REPLACED AS A PRECAUTIONARY PROCEDURE AND OPERATIONAL CHECKS WERE PERFORMED AGAIN AND CHECKED GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.