The use of the term ECU may be used to refer to an Engine Control Unit, however ECU also refers to an Electronic Control Unit, which is a component of any automotive mechatronic system, not just for the control of an engine. In the Automotive industry, the term ECU often refers to an Engine Control Unit (ECU), or an Engine Control Module (ECM). If this unit controls both an engine and a transmission, it is often described as a Powertrain Control Module (PCM). For the purposes of this article, we will discuss the ECU as an Engine Control Unit.