What was found
FOR FLIGHT 3716 AFTER PUSHBACK THE AUXILLIARY POWER UNIT SHUTDOWN BY ITSELF AND SMOKE WAS REPORTED BY 2 PASSENGERS SITTING IN SEATS 18A AND 18B. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE AFT AUXILLIARY POWER UNIT REMOTE SWITCH IAW AMM 4-43-03. THE OPERATIONAL TEST FOUND THE AUXILLIARY POWER UNIT OIL WAS OVERSERVICED. SERVICED THE AUXILLIARY POWER UNIT OIL IAW AMM 12-13-49. RAN THE AUXILLIARY POWER UNIT FOR 1 HOUR WITH NO SMOKE PRESENT. THE AIRCRAFT WAS RETURNED TO SERVICE.