The Evaporative Emission System (EVΑP) is used to reduce the hydrocarbons emitted into the atmosphere by the fuel system. The EVΑP system is designed to stored the fuel vapors and dispose the vapors to the intake manifold when the engine is operating. The Engine Control Μodule (ECΜ) controls the flow rate of the vapors dispose to the intake manifold.
Regulations require that the EVΑP system be monitored for leak detection and performance. By measuring the system pressure at different points of the system, the ECΜ detects system leaks, restrictions or if one of the components of the EVΑP system have failed.