P0497 - EVAPORATIVE EMISSION (EVAP) SYSTEM - LOW PURGE FLOW

The DTC code P0497 OBDII is configured when the PCM (Powertrain Control Module) finds a purge flow rate of the EVAP (Evaporative Emissions Control System) system which is lower than expected.

The EVAP system captures and contains the fuel vapors, then it sends them to the engine to be burned before they escape into the atmosphere. This system is sealed by the fuel filler cap, a venting valve that allows air to enter so that the fuel vapors are displaced to the engine by a purge valve that allows the vapors to pass into the engine.

The fuel vapors remain in the coal can until a certain pressure is reached which has already been established by the manufacturer. When pressure is reached, the PCM orders the opening of the ventilation valve on or near the carbon canister to bring in the fresh air, at which time the fuel vapors are sucked by the engine out of the activated carbon filter. The actual flow rate with the expected flow rate is compared by the PCM to control both the opening and closing of the bleed valve, thus allowing the flow rate values to match. If the PCM determines that the flow rate required to purge the system is less than expected, this code is set and the Check Engine light is illuminated.

• Engine malfunction light (MIL) on.
• Lowers fuel efficiency.
• Problems when the engine slows down.

The reasons for setting the fault code P0497 OBD2 are:

• There may be cracked vacuum hose lines.
• Solenoid related cables may be defective causing a short in the circuit.
• The bleed valve solenoid may be in bad condition.
• Perhaps the EVAP pressure sensor is damaged.

To correctly solve the defects caused by the diagnostic code P0497 OBDII, you must do the following:

• Consult the TSB (Technical Service Bulletins).
• Visually inspect all cables and connectors that are related to the system. Also, check vacuum lines and hoses. You should repair or replace any of these components if you find defects.
• If there is carbon residue when inspecting the vacuum lines, a cartridge may be defective. Change the cartridge, then delete the code.
• If the code returns, you should check the EVAP bleed valve solenoid. Refer to the service manual for the specifications of that solenoid. Then, use a scanner to activate the solenoid and check the vacuum flow while the engine is running. If the solenoid does not open when activated, check the system voltage and ground signals and compare them to the manufacturer's specifications. If everything is right, the solenoid may be defective, you should replace it.
• If there are problems in the system circuits, you should test them with a digital multimeter. Repair circuits that indicate a short.