DTC P0496: Evaporative Emission (EVAP) System High Purge Flow: General Description

The engine control module (ECM)/powertrain control module (PCM) adjusts the amount of fuel vapor sent to the engine by controlling the evaporative emission (EVAP) canister purge valve. If the EVAP canister purge valve is stuck open, engine vacuum flows into the purge line before purge control starts when starting the engine. The ECM/PCM monitors the fuel tank pressure (FTP) sensor output when purge control starts. If the FTP sensor output indicates negative pressure, the ECM/PCM detects a malfunction in the EVAP canister purge valve, and a DTC is stored.