Write an article based on this "Use a car scan to test the EGR valve. Locate the OBD-II data connector. Turn the ignition to the on position. Connect the scan tool to the OBD-II data link connector. Read the results."
A scan tool reads information from your On-board Diagnostics, version II (OBD-II) system. This system collects information from the sensors in your engine. If the sensor detects something wrong, it reports it as an error code to the OBD-II. A scan tool allows you to read this code. The scan tool plugs into OBD-II data link connector, which is usually located under the dash. The most common location for the OBD-II connector is under the dash by the steering wheel. The owner's manual should have the exact location if you have trouble finding it. Place your key in the ignition and turn it to on, but do not start the engine. You only want the electrical systems running. The scan tool will prompt you to fill in some information about your vehicle. It usually requires information about the make, model, engine, and year of the vehicle. Most scan tools draw power from the vehicle’s battery and do not require a separate power source. The scan tool will display any error codes the OBD-II reports. If the result is in the P0400 to PR409 range, then the EGR valve may be faulty.