As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN PRESSURIZATION CONTINUES TO CLIMB AFTER LEVEL OFF AT 100-200 FEET PER MINUTE. MANUAL AND AUTO MODES FAIL TO CONTROL CABIN RISE. AIR TURN BACK TO BGY. CLEANED OUTFLOW VALVES, WIPED DOWN SEALS. GRUOND TEST OK FOR SERVICE IAW MM 21-30. (M)