As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SPLIT IN DUCT PRESSURE BETWEEN LEFT AND RIGHT DUCT. GROUNDED - YES. CREW OBSERVATION LH 5PSI AND RH 20PSI. IAW B737-900 FIM 36-10 TASK 804 FOUND HIGH STAGE VALVE VALVE STICKING. REMOVED AND REPLACED ENG #1 HIGH STAGE VALVE IAW B737-900 AMM 36-11-06. NO LEAK CHECKS NOTED DURING LEAK CHECK. RAN BOTH ENGINES, NO DUCT SPLIT NOTED.