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P0455 Code: Meaning, Symptoms, Causes, and Fixes 

  • Cars Explained
  • Silas Smith
  • 5 minutes

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Car owners usually have a hard time finding what is wrong with their vehicles. Since the engine computers are always on the lookout for malfunctions, it is easy to know what is wrong with the car. But since the computer communicated in error codes it is important to know what each of these engine codes means.


The P0455 code is one such engine code that arises due to leaks in your fuel control system.  Read more about everything from what it means, causes, symptoms, and how much it costs to fix the P0455 code.  

What does error code P0455 mean? 

The P0455 OBD-II code means the engine computer has detected an Evaporative Emissions Control System (EVAP) Malfunction or to be precise a ‘Gross Leak Detected’. Basically, this means there is a large leak in the EVAP system. 

The EVAP system captures the fuel vapors evaporating from the storage system and releases them back into the combustion process. These gases are absorbed by the EVAP canister, which will purge it right back to the intake manifold when the vent control valve opens and lets fresh air inside. These fuel vapors are harmful to the atmosphere  

What are the symptoms of this engine code? 

In most cases, there will not be any P0455 symptoms that could be easily detected. But there are mainly a few common symptoms that might be related to the P0455 engine code.  

  • Fuel odor due to release of fuel vapors (usually near the tank area or filler area): These vapors may also escape through the evaporative lines that run to the intake system. 
  • Decrease in fuel economy 
  • Check Engine Light will illuminate: This is the common sign of major leaks in the EVAP system. 

Can I drive with a P0455 code? 

Before answering this question, you need to have answers to another important question- ‘is a p0455 code bad?’. Yes. It is bad not only for the environment but for your car’s fuel economy as well. So, it would be better to diagnose and find a suitable emission code P0455 fix. 

You can drive for a short distance (say 30-50 miles) with the P0455 OBD code. Unless you see there are fuel leaks or the fuel odor gets really strong, you can keep driving. But unless you find a P0455 code fix, a large leak in the EVAP system can cause major fuel economy issues. 

What causes the P0455 code? 


Since we now know that a leak in the EVAP system causes a P0455 code, let us see what are the factors that may lead to the leak. Here are some of them. 

  • Gas Cap: The error may occur if the gas cap is loose, leaking, broken, or missing. 
  • EVAP hoses: If the hoses are disconnected or damaged due to old age. 
  • Vent control valve: Stuck or defective valves can cause leaks. 
  • Purge control valve: Stuck or defective valves can cause leaks. 
  • EVAP Canister: Cracks or other damage in the canister can lead to major leaks in the system. 

How to diagnose P0455 code 

Here are a few ways to easily diagnose the P0455 code. 

  • Inspect the gas cap. 
  • Visual inspection for any obvious leaks. 
  • EVAP smoke test to look for leaks. 

A professional will first use an OBD-II scanner to diagnose this issue. The technician will reset the code and do a road test to see if the problem still exists. He also makes sure the code is not paired with other error codes like P0441, P0440or P0456. 

How to fix a P0455 code 

The first step is to see whether the gas cap is missing or damaged. With age, there are chances for the cap to get loose or deteriorate. Replacing the cap can most likely solve the problem. The Engine Check light will turn off and the code will erase after a few drive cycles. 

If this does not fix the issue, the EVAP hoses from the gas tank to the canister and from the canister to the air intake must be examined. If these are broken or disconnected, connect them back or replace them. 

In the case both the above fixes fail, a smoke test will reveal any leaks that you were not able to pick up. Both the purge valve and vent control valve has to be subjected to electrical testing and has to be replaced if any malfunction has been identified. 

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How much does this code cost to fix? 

For an EVAP system repair, the maximum cost can be up to $6000. But this arises only when there is major damage like structural instability of the EVAP system.  

On the other hand, a new gas cap will cost you between $20 and $60, given it is missing or damaged. Similarly, a vent control or purge valve can be around $150-$300 each. If the EVAP canister has to be replaced, you will have to spend between $400 and $600. Additionally, the EVAP hoses or lines can also cost somewhere between $20 and $100 each. 


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