Nissan Altima P0455 Code Diagnosis

This is one of the most commonly encountered trouble codes for the Nissan Altima The Code P0455. This code is used to refer to the number given when your Altima goes into an OBDII scanner. If there's a problem, P0455 means that it is. Leakage large In the evaporative emissions control system. This code is often found with or related to P0420,P0441 and, very frequently, P0440.

Your Altima’s drive-ability is usually not affected by P0455. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though. It often comes with the P0442. More information is available at Nissan Altima P0442 OBDII Cod.

Nissan Altima P0455 Definition

P0455 refers to a general OBDII trouble code. It means that no matter what make or model vehicle you have, this code will always mean the exact same thing. Technically, the code stands for:

System Gross Leak – Evaporative Emission System

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

Nissan Altima P0455 OBDII Code Symptoms

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

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

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.

Altima Trouble Code P0455

Many things can lead to the P0455 code being triggered in your Nissan Altima. The most frequent problems that trigger this code are:

• 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 main problem that can cause 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. 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. This could cause a drop in tank pressure which can throw off 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. 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.

P0455 Diagnosis- Nissan Altima

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

• You will be asked by the mechanic to check for additional 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. These include the line and purge valve.
• A mechanic will examine the gas cap and verify that it is able to withstand high pressure. 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 Nissan Altima, 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

These are some of the most popular Altima P0455 fix:

• Replacement of gas cap
• Replacing EVAP lines
• Replace charcoal canister
• Replacing 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 check your gas cap.

You will need to solve the problem quickly. We trust this helped. You can add any additional information by leaving a comment.

Do you consider P0455 to be a serious concern?

While P0455 is not going to cause the Altima’s engine to stop running, it should not be treated lightly. Fuel leaks could be a problem. Check your tank regularly to make sure there is no fuel leaking. It is best to have it checked and/or dealt with immediately.