P0496 Code: Meaning, Causes, and Symptoms | OBD2 Codes

P0496 – Evaporative Emission System High Purge Flow

 

P0496 Possible Symptoms

 

Engine Light ON (or Service Engine Soon Warning Light),Engine misfire,Engine hard start

 

P0496 Possible Causes

 

Faulty EVAP Canister Vent Valve,Faulty EVAP Canister Purge valve,Plugged EVAP canister condition,Faulty EVAP Pressure Sensor,EVAP Canister Vent Valve harness is open or shorted,EVAP Canister Vent Valve circuit poor electrical connection

 

P0496 Description

 

The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the PCM will command the EVAP purge valve open, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent valve open, fresh air will be drawn through the valve and vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge valve into the intake manifold to be consumed during normal combustion. The EVAP system requires the PCM be able to detect a leak as small as 0.040 inch in the EVAP system. The PCM uses several tests to determine if the EVAP system is leaking.