The engine is fitted with an engine management system (3) as well as a security system (6). The two systems are linked by a data line (5) which provides data to enable the engine to be started if the security release has been accepted ie. if the user has provided the ID code when starting the engine. The direct data link provides a more rapid release of the engine starting procedure as well as providing a more secure protection for the vehicle. The two systems operate to a preset protocol.
