Abstract: A method of controlling a vehicle engine system is described. The method involves sensing a pressure in the engine; generating a signal indicative of the sensed pressure; encrypting the signal to generate an encrypted data message containing information indicative of the sensed pressure; transmitting the encrypted data message to an engine control means; decrypting the encrypted data message to obtain the information indicative of the sensed pressure; and controlling the vehicle engine system in dependence upon the information contained in the encrypted data message. A pressure sensor for use in the method, and a suitably programmed electronic control unit are also described.