What was found
AFTER TAKEOFF, RECEIVED A MASTER WARNING FUSELAGE DOOR SWITH LIGHT. RAN CHECK LIST, RETURNED TO FIELD. NO PRESSURE PROBLEMS NOTED. AFT CARGO DOOR RED LIGHT ON MFD ASSOCIATED WITH MASTER WARNING. REMOVED FROM SERVICE. PSEU INDICATES ABDRLK FAULT UNRSNABLE FAR IN FAULT HISTORY. ADJUSTED INDUCTANCE CHECK OF ABDRLK PROXIMITY SENSOR TO NOMINAL NEAR RIGGING GAP TOLERANCE IAW AMM 32-61-00-280-801, GAP M/H STARTED AT 8.164, ENDED AT 8.675. OPS TEST GOOD. RETURNED TO SERVICE.