As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB UP TO FL340 #1 BLEED DUCT PRESSURE INDICATED 70-74 PSI #2 BLEED DUCT PRESSURE INDICATED 40-45 PSI. BOTH INDICATED 35 PSI AFTER POWER REDUCTION IN CRUISE FLT. GROUNDED - YES. MANUALLY TESTED OPERATION OF PRSOV REF B737-9 AMM 36-00-00 AND VALVE FAILED TO STAY OPEN WITH PNEUMATIC PRESSURE APPLIED. #1 ENGINE PRSOV REMOVED AND REPLACED W/SERVICEABLE UNIT PER B737-9 AMM 36-11-04.