Ford F150 P0455: EVAP System → Leak Detected (Large)

This is one of the most commonly encountered trouble codes for the Ford F150 The Code P0455. The trouble code refers to a number you receive when your F150 is plugged into an OBD2 scanner. It has to do the emission system. If there are any problems, P0455 indicates they have been fixed. Large leak It is part of the evaporative emission management system (EVAP). It is frequently found alongside, or closely related to, other codes like P0420/P0430/P0441 and most often, P0440.

P0455: EVAP System → Leak Detected (Large)

The P0455 issue is not usually a threat to your F150's driveability. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though.

Ford F150 P0455 Description

The universal OBDII code P0455 can be used to diagnose trouble codes. It means that no matter what make or model vehicle you have, this code will be the same (F150). Technically, the code stands for:

System Gross Leak Evaporative Emission System

The EVAP captures any fuel vapor in the fuel tank. They are then sent to the intake of the engine to start the combustion process. When there is a large leak in the Ford F150’s EVAP system, it will throw the P0455 OBDII Code.

Ford F150 OBDII Code Symptoms

A P0455 Code will usually not cause any symptoms except the ones listed below. Smells like gas The service engine soon light. The slightest drop in fuel economy may also be noticeable.

The fuel tank and fuel filler tubes should smell particularly strong.

The EVAP system is responsible for fuel vapors. If these vapors are leaking from the system, you’ll often smell them faintly while operating the vehicle.

F150 P0455 Trouble code Causes

P0455 Trouble code in Ford F150 can trigger by several things. These are some of the more common issues that can trigger the P0455 trouble code in your Ford F150.

• Hose for Evap System– The hose that carries the fuel vapor from the fuel tank to the intake manifold can begin to leak. The P0455 error code will be generated. It should be checked for tears or holes. This is the leading cause of code.
• Vapor Canister Purge Valve– One of the most common causes of the P0455 code is the vapor canister purge valve. It’s really easy to replace. There are some clips you will need to look for and then remove.
• A Faulty Canister of Charcoal– The charcoal canister is often the cause of P0455.
• Fuel Tank Sending Unit– It is possible for the gasket that attaches the fuel sending unit to the gas tank to go bad. It can lower the tank pressure, which could throw out the code.
• Capacity for Fuel– A bad fuel cap can cause the code to be thrown for sure. Often, you’ll get a message informing you that the fuel cap is off even when it is on. You may not get the message but a P0455. This will save you time and money.
• Fuel Filler Neck– There is often a gasket where the fuel filler neck connects with the gas tank. It is possible for this gasket to dry, particularly if vehicles spend a lot of time in dry environments. When it dries out, the fuel tank can’t hold pressure anymore.

Ford F150 Diagnosis - Page 0455

To diagnose the problem with your Ford F150's P0455, a mechanic can use a variety of tools. The most commonly used methods to diagnose this code are:

• A mechanic will usually check for any additional trouble codes. It is easier to diagnose problems if there are more codes. That’s because when they appear together in certain combinations, there will often only be only a few conditions that will throw any combination of codes at one time.
• The mechanic will normally determine what trouble codes are associated with P0455. Take a look at the EVAP system. It includes the purge valve and line as well as the canister.
• To ensure that the cap can withstand pressure, the mechanic will check it. If you are getting a warning that your gas cap is off, even when it’s on, replacing it will more than likely clear this code.
• Monitoring and checking the fuel tank pressure is a must.
• The mechanic will then perform the following tests after completing the above-mentioned checks:
• A smoke test, and they’ll use a scan tool to confirm that the EVAP solenoids and valves are operating properly.

Here’s a pretty good video on diagnosing these leaks from Scotty Kilmer, if you are interested:

While the trouble code may state that there is a “large leak” in the EVAP system of your Ford F150, the actual leak will most likely still look rather small. The “large” really is referring to how much pressure is being lost.

P0455 is the most common fix

These are some of the more common F150 P0455 repairs:

• Replacing the gas cap
• Replacement for EVAP Line
• Replace charcoal canister
• Change the fuel tank

You should start with the gas caps and move on to the fuel tanks. This is because the gas caps are the easiest to replace and the least costly.

Here’s a great video on How to test your gas tank.

You will need to find the root cause of your Ford F150 throwing the P0455 error code. This should help. Please feel free to add anything below.

Do you consider P0455 to be a serious concern?

While P0455 is not going to cause the F150’s engine to stop running, it should not be treated lightly. There could be fuel contamination. You should pay extra attention to the level of your fuel tank and ensure that you're not leaking fuel. It is best to have it checked and/or dealt with immediately.