The Evaporative Emissions Control System (EVAP) is designed to capture fuel vapors and send them to the engine, where they can be burned. This system has an activated carbon canister where the vapors are stored, a pipe that connects the canister to the fuel tank, and an engine inlet. Two valves control the storage and flow of the vapors.
Monitoring and controlling the EVAP system is the Engine Control Module (ECM). If the ECM finds a malfunction in the vent valve circuit, it will set the diagnostic code P0498 OBDII.