As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DOOR 2R SQUEALS THRU 18000 FT. FOUND OUTFLOW VALVE AS THE CAUSE. OUTFLOW VALVE HAS SEAL DAMAGE AND MISSING WHERE DOORS CLOSE TOGETHER. REPLACED OUTFLOW VALVE. PRESSURIZED AC TO 6.5 PSI WITH NO NOISE. MED SEAL AND SURFACES CHECKED GOOD.