Subaru Outback Code Diagnosis

The most frequent trouble code with the Subaru Outback Is the Code P0455. This code is used to refer to the number given when your Outback goes into an OBDII scanner. If there's a P0455, it means that there are a 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.

The P0455 issue is not usually a threat to your Outback's driveability. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though. It's often associated with P0442. More information is available at Subaru Outback OBDII Code P0442

Subaru Outback Definition P0455

The universal OBDII code P0455 can be used to diagnose any problem. It means that no matter what make or model vehicle you have, this code can mean the exact same thing. Technically speaking, it stands for:

System Gross Leak – Evaporative Emission System

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

Subaru Outback OBDII Codes Symptoms

A P0455 Code will usually not cause any symptoms except the ones listed below. The smell of gas The service engine soon light. It is possible to notice a slight dip in fuel economy.

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

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.

Outback P0455 Troublecode Causes

The Subaru Outback's P0455 Trouble Code can be triggered by many factors. These are some of the more common issues that can trigger the P0455 code.

• Evap Hose– 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 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.
• The Faulty Charcoal Caister– 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. 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.

Subaru Outback Diagnosis - P0455

The mechanic will have a lot of different tools at his disposal in order to determine the cause of your Subaru Outback P0455. These are some of the common diagnostics that can be done for the code

• A mechanic will often check to make sure there are no other codes. A mechanic will usually check for additional trouble codes to help diagnose the problem. 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. These include the line and purge valve.
• 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 Subaru Outback, the actual leak will most likely still look rather small. The “large” really is referring to how much pressure is being lost.

Most common P0455 fixes

Below are the top Outback P0455 fix options:

• Replacing the gas cap
• Replacement for EVAP Line
• Replace charcoal canister
• Replacing 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.

We wish you all the best in finding out why your Subaru Outback is throwing the code P0455. This should help. 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 Outback’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. You should immediately take it in for repair or replacement.