As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT DUCT PRESSURE VARIED IN CLIMB FROM 20PSI TO 5PSI. AT LEVEL OFF STABILIZED AT 5PSI. RIGHT DUCT PRESSURE STABLE AT 42PSI ENTIRE FLT. FOUND BROKEN SENSE LINE FROM INTERSTAGE DUCT TO BLEED AIR REGULATOR, REMOVED LINE. REPLACED SENSE LINE IAW AMM 36-11-03-400-801 D.(4). LEAK CHECKS GOOD.