As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENROUTE, RIGHT PRESSURE SHOWS 45 PSI AND LEFT SHOWS 25 PSI (FL340). ACFT GROUNDED. R & R THE NR 1 ENGINE PRE-COOLER CONTROL VALVE, IAW AMM 36-12-02-000-801 AND 36-12-02-400-801. LEAK & OPS CHECKED GOOD. ACCOMPLISHED NR 1 ENGINE BLEED AIR SYS HEALTH CHECK IAW TC NG-36WC-00001. OPS CHECKED GOOD.