Mazda 3 Code Diagnosis

The most frequent trouble code with the Mazda3 The Code P0455. The trouble code refers to a number you receive when your 3 is plugged into an OBDII scanner. The code P0455 indicates that there are a few problems. Large leak It is part of the evaporative emission controller system. This code is often found with or related to P0420,P0441 and, very frequently, P0440.

Your 3.'s drive-ability is usually not at risk from P0455. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though. It may also be accompanied with P0442. More information is available at Mazda 3 OBDII Code P0442.

Mazda 3 P0455 Definition

P0455 refers to a general OBDII trouble code. The code can be used regardless of the make and model of the vehicle. Technically speaking, this code refers to:

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 Mazda 3’s EVAP system, it will throw the P0455 OBDII Code.

Mazda 3 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. It is possible to notice a slight dip in fuel economy.

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

Fuel vapors are dealt with directly by the EVAP. If these vapors are leaking from the system, you’ll often smell them faintly while operating the vehicle.

3 P0455 Trouble Code Reasons

Many things can trigger the P0455 code in Mazda3. The most frequent problems that can trigger the P0455 trouble code in your Mazda 3 are:

• Hose of the 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. You should look for a hole or a tear in the code. 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. 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. The gasket may dry out especially if the vehicle is in dry conditions. When it dries out, the fuel tank can’t hold pressure anymore.

Mazda 3. P0455 Diagnoses

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

• The 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.
• Once the mechanic has determined the trouble codes associated with P0455, he or she will usually Take a look at the EVAP system. It includes the purge valve and line as well as the canister.
• 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.
• Following the inspections and repairs, the mechanic will conduct two more tests.
• 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 Mazda 3, 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 the 3 most popular P0455 solutions:

• Replacement of 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 most cost-effective and easiest to replace.

Here’s a great video on How to check your gas cap.

It's a good idea to try and figure out why your Mazda 3 is throwing the P0455 code. We trust this helped. Please feel free to add anything below.

Are P0455 Serious Concerns?

While P0455 is not going to cause the 3’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.