Ford F250 P0455: EVAP System → Leak Detected (Large)

This is one of the most commonly encountered trouble codes for the Ford F250 The Code P0455. This code is used to refer to the trouble code for your F250. The P0455 code indicates that an emission problem exists. Large leak In the evaporative emissions control 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 F250's driveability. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though.

Ford F250 Definition P0455

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 can mean the exact same thing (F250). Technically the code is:

System Gross Leak Evaporative Emission System

The EVAP system collects fuel vapor from fuel tanks and then sends it to the intake to ignite the engine in normal combustion. When there is a large leak in the Ford F250’s EVAP system, it will throw the P0455 OBDII Code.

Ford F250 OBDII code Symptoms

The P0455 code is usually not accompanied with any other symptoms than those listed. Smells like gas And the service engine soon light. The slightest drop in fuel economy may also be noticeable.

Particular attention should be paid to the fuel tank or fuel filler tube smell.

The EVAP process deals with fuel vapors directly. If these vapors are leaking from the system, you’ll often smell them faintly while operating the vehicle.

F250 P0455 Trouble code Causes

P0455 code can be triggered in Ford F250 by many factors. The most frequent problems that trigger this code are:

• Evap Hose– The hose that carries the fuel vapor from the fuel tank to the intake manifold can begin to leak. This can lead to the P0455 code. You should look for a hole or a tear in the code. This is one of most frequent causes for the 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. You'll need to identify and remove a few clips.
• 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.
• Fuel Cap– 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. It may be worth your time to get that message and a P0455 to ensure you don't waste any 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 F250 Diagnosis - P0455

The mechanic will have a lot of different tools at his disposal in order to determine the cause of P0455 on your Ford F250. 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.
• Monitor and check the pressure in your fuel tank.
• 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 F250, the actual leak will most likely still look rather small. The “large” really is referring to how much pressure is being lost.

The Most Popular P0455 Fixes

Below are the top F250 P0455 solutions:

• Replacing the gas cap
• Replacing EVAP lines
• Replace charcoal canister
• Change the fuel tank

It is best to begin with the gas cap, and then work your way up to the fuel tanks. The gas cap is the most difficult and cost-effective item to replace.

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

It's a good idea to try and figure out why your Ford F250 is throwing the P0455 error code. We trust this helped. Please feel free to add anything below.

Do you consider P0455 to be a serious concern?

While P0455 is not going to cause the F250’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. You should immediately take it in for repair or replacement.