As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT 16,800` CABIN DOOR ANNUNCIATOR & RED CABIN ALTITUDE WARNING ILLUMINATED. CABIN ALTITUDE CLIMBED TO 12,600’. FOLLOWED EMER CHECKLIST, DECLARED AN EMER TO FACILITATE DESCENT TO 10,000’. ACFT DIVERTED & LANDING WAS UNEVENTFUL. MX TROUBLE SHOT THE DISCREPANCY TO A FAULTY VENT DOOR PROX SWITCH & SOLENOID. OPERATIONAL & PRESSURIZATION CHECK ACCOMPLISHED WITH NO DEFECTS NOTED. ACFT WAS RETURNED TO SERVICE.