P0496 - EVAPORATION FLOW DURING NON-PURGE CONDITIONS

The diagnostic code P0496 refers to the EVAP system (Evaporative Emission Control System). The PCM (Powertrain Control Module) closes the EVAP system (The evaporative emission control system) through the purge valve. At the right time, the PCM commands the purge valve to open, allowing engine vacuum to be applied to the EVAP vessel. When this valve is open, fresh air is drawn through the vessel, resulting in the extraction of fuel vapors to the carbon.

Likewise, the PCM (Powertrain Control Module) monitors the FTP sensor (Fuel Tank Pressure Sensor) to determine if the EVAP system is taking on vacuum. If the vacuum taken from the EVAP exceeds the default value in a predetermined time, the DTC code P0496 OBD2 is set.

• The Check Engine light is activated.
• Problems when starting up.
• The engine can run rich.

The reasons why the fault code P0496 OBD II can be set are:

• The ventilation valve may be defective.
• The EVAP system vessel may be blocked.
• Error in the Evaporative Emission Control System caused by a faulty FTP sensor.
• Leaky Evaporative Emission Control System (EVAP) hose.

When faced with the code P0496, you can do the following for correct repair:

• With the key in the ignition position and the engine off, using the preference scanner, it seals the Evaporative Emission Control System (EVAP) through the purge seal function. Watch the Fuel Tank Pressure (FTP) sensor reading when the purge is turned off. Compare the result with the manufacturer's specifications and if they are not within the expected parameter, change the EVAP container purge solenoid valve.
• If you do not have access to a scan tool, disconnect the vacuum line at the purge valve that has a return to the carbon canister. Disconnect the electrical connector from the bleed valve. Start the engine and you can put a finger on the valve, at the point where you disconnected the vacuum line. If you feel a vacuum, you must change the bleed valve.
• Also, to check the condition of the bleed valve, you can simply remove it and blow it out. It should be closed, that is if air passes it has to be replaced.
• If the tests before the bleed valve have been successful, the problem may be in the Fuel Tank Pressure Sensor (FTP). To check it, you must use a high-end scanner and monitor the tank pressure with the gas cap removed. If this test shows a vacuum, the fuel cap should be removed. If the sensor shows a vacuum while the cap is removed, the problem is with the FTP sensor, you can change it.