As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ATB - DUE TO 4L DOOR UNLOCKED INDICATION. CORRECTIVE ACTION: INSPECTED LOCKING MECHANISM AND PERFORMED CABIN PRESSURE TEST. FWD TO MEL AS PRECAUTIONARY. THEN R/R PROX SENSOR 3MJ AND CLEANED, LUBED, AND RIGGED DOOR LOCK MECHANISM. OK FOR SERVICE.