The EVAP system (The evaporative emission control system) ensures that the fuel system of the vehicle is sealed in such a way as to prevent the escape of vapors from the tank into the atmosphere. This system protects the atmosphere from the pollutants resulting from the vapors produced. This system has a pump, which detects internal leaks inside the tank. Once the ignition switch is turned off, a negative pressure or vacuum is created in the EVAP system.
The Powertrain Control Module (PCM) constantly checks the system for such leaks. If it determines that the pump has failed to activate as required, or that vacuum was not created as required, a DTC P2418 OBDII code will be stored.