As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WITH BOTH PACKS IN AUTO AND BOTH BLEED SWITCHES ON, THE LEFT BLEED DUCT PRESSURE READS 20 PSI AND THE RIGHT READS NEAR ZERO. ACFT GROUNDED. PERFORMED PNEUMATIC SYSTEM TROUBLESHOOTING IAW AMM 36-11-00, FOUND PRSOV NOT OPERATING CORRECTLY. REMOVED AND REPLACED PRSOV IAW AMM 36-11-04, NO LEAKS NOTED. RT DUCT PRESURE NORMAL. SUCCESSFUL GROUND VERIFICATION ACCOMPLISHED.