As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB, DUCT PRESSURES DISPLAYED A SPLIT, LEFT 22, RIGHT 44. MATCHED DURING CRUISE. ACFT GROUNDED. REMOVED AND REPLACED THE PRE-COOLER CONTROL VALVE IAW AMM 36-12-02-000-801 AND AMM 36-12-02-400-801. REMOVED AND REPLACED THE HIGH STAGE VALVE IAW AMM 36-11-06-000-801 AND AMM 36-11-06-400-801.