The EVAP (Evaporative Emissions Control System) is designed to stop fuel vapors before they are released into the atmosphere. A vented tank known as a canister is used to store these excess vapors in this system until they can be completely burned off in the proper condition.
The components of the EVAP System are the charcoal canister, pressure sensor, purge valve or solenoid, vent valve or solenoid. Besides that, there are some tubes and hoses that are routed from the fuel tank to the engine. The Evaporative Emissions Control System uses an engine vacuum to take fuel vapors to the intake manifold. These vapors are burned there so they cannot be expelled into the environment.
The EVAP Pressure Sensor that monitors system pressure is usually located in the fuel tank and is built into the fuel pump housing itself. If the tank or EVAP system pressure is out of the established limits for more than the allowed time, the P0450 OBDII diagnostic code will be set.