This disclosure relates to a method of configuring an engine control system for controlling the engine of a vehicle. The method involves displaying one or more graphical representations of functional elements to be performed by the engine control system and then modifying the one or more functional elements by making changes to the displayed graphical representations. This allows the engine control system to be readily reconfigured by a user. This disclosure also relates to an apparatus for configuring an engine control system and a new engine control system. A computer program product including a computer readable medium having a computer program recorded on it for configuring an engine control system is also disclosed.