The engine of vehicles with an Evaporative Emission Control System (EVAP) extracts excess fuel vapors. The vapors are extracted from the fuel tank, otherwise, they can be released into the atmosphere. These vapors are directed into the engine inlet through a vacuum line. When they reach the engine inlet, the purge valve that is controlled by the Powertrain Control Module (PCM) measures the number of fuel vapors.
The Powertrain Control Module (PCM) constantly monitors the purge control valve and when it observes that there is no change in voltage concerning the valve, the fault code P0444 OBD2 is established. It can also be set if the readings obtained from the EVAP system are not under the manufacturer’s parameters.