As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 2002. PRESN AUTO FAULT ADVISORY MESSAGE DISPLAYED ON EICAS. ELECTED TO RETURN TO THE FIELD AND ACCOMPLISHED A UNEVENTFUL LANDING. PLACED ON MEL 21-31-01A. RETURNED TO SERVICE. MEL CLEARED 10/01. DUE TO RECENT A/C HISTORY FOR FAULT CODE 21311009CPC BEING FOUND TRANSITORY, REPLACED OUTFLOW VALVE REF FIM TASK 21-31-00-81-819-A STEPS 6 K-L. OPS TEST GOOD. PLACARDS REMOVED. CLEAR MEL. RETURNED TO SERVICE.