A method of authenticating an automotive device connected to an engine control system that stores an authentication code in memory of the automotive device that is generated by an encryption algorithm using an identification code of the automotive device as a seed value. The engine controller determines a verification code using a complementary encryption algorithm that also uses the identification code received from the automotive device as a seed value. The engine controller compares the authentication code to the verification code, and indicates that the automotive device is not authentic if the authentication code does not correspond to the verification code. Advantageously, authenticating the automotive device will be done autonomously by the engine controller without prompting by a technician using special equipment such as a laptop computer.