How to Reset the P0456 on a Ford (with Video)

P0456 is a diagnostic trouble code pertaining to leaks in the vehicles fuel vapor management system. The code is often set by failure to properly seal the gas cap after filling the tank, or from leaving the engine running while filling up at the gas station. The code can also be caused by a damaged fuel vapor line, a bad seal in the evaporative emissions system, a leak at the purge valve or a leak in the vapor canister. After you have determined the cause of failure and corrected it, you can clear the code out.

1. Connect the scan tool to the Ford’s diagnostic port

Connect the scan tool to the Ford’s diagnostic port, located next to the steering column under the driver’s side of the dashboard. The port will have a small cover over it with the letters “DTC” embossed on the face of the cover. Pull that cover off to access the port.

You can purchase a scan tool at your neighborhood auto parts store. Make sure the scan tool you are interested in buying works with Ford vehicles.

2. Run a self test on the system

Run a self test on the system by following the directions in your scan tools specific owner’s manual. When the codes are read, make sure the P0456 is the only code present before erasing the codes. If another code is present, you will need to have it diagnosed and corrected before you clear the codes.

3. Erase the code when prompted to do so

Erase the code when prompted to do so by the scan tool. Complete the self test and disconnect the scan tool. Replace the diagnostic port cover.

Video Demonstration

Tips and Warnings

If you pull a P0456 when reading codes, the first thing you should do is make sure your gas cap is on securely. If it isn’t, tighten it down properly and clear the code out. If the light returns within the next hundred miles of driving, you should have the code diagnosed by a certified driveability technician.

Never leave your engine running when filling your tank. This can cause the power train control module to assume it is detecting any of several malfunctions due to the lost pressure in the fuel vapor system and the upward mobility of the fuel level sensor. Additionally, never top off the gas tank after the station’s pump clicks off. The additional gas you pump in can flow into the evaporative fuel system and cause damage which will cost you far more than the price of a tank of gasoline to repair.