As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRESSURE FLUCTUATING BETWEEN 8000-8300 AT 37000 FT. FLIGHT DIVERTED. AUTO AND MANUAL PRESSURIZATION INOP COULD NOT RECOVER CONTROL W/ THE MANUAL SYSTEM PER CHECK LIST. REMOVED AND REPLACED PNEUMATIC AND ELECTRO PNEUMATIC OUTFLOW VALVES IAW 21-31-03 AND 21-31-04. COMPLIED WITH OPS CHECK IAW 21-31-00, OPS CHECK GOOD. PERFORMED TEST FLIGHT AT FL 37 NO DISCREPANCIES NOTED. AIRCRAFT RELEASED AND RETURNED TO SERVICE.