As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB, PASSING FL290, NOTICED DUCT SPLIT 45L 15R PSI. AFTER LEVEL OFF SPLIT WENT AWAY 41 PSI L/R. NO SPLIT DURING REMAINDER OF FLIGHT NOTED. ACFT GROUNDED. R & R NR 2 ENG PRECOOLER CONTROL VALVE REF MM 36-12-02-000-801 AND 36-12-02-400-801. OPS CHECKED GOOD. COMPLIED WITH ENGINE BLEED AIR CROSSOVER OPS TEST IAW MM 36-11-00-710-801. OPS CHECKED OK.