What was found
DURING TAXI FOR TAKEOFF, FLIGHT CREW RECEIVED A 'APU INLET/EXHAUST DOOR ALERT', FAIL TO CLOSE INDICATION. DUE TO MEL RESTRICTIONS, FLIGHT CREW ELECTED TO RETURN TO GATE FOR MAINTENANCE ACTION. AIRCRAFT RETURNED TO GATE WITHOUT FURTHER INCIDENT. MAINTENANCE REP COMPLIED WITH MEL PROCEDURES AND ASSIGNED DEFERRAL TO APU INLET/EXHAUST DORS INOPERATIVE. INITIAL INDICATIONS ARE THAT APU DOOR ACTUATOR HAS FAILED. AIRCRAFT RETURNED TO SERVICE. (M)