P0455 Code (Symptoms, Causes, and Fixes)

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Okay, so you’ve been noticing some unusual symptoms and decided to troubleshoot your car, now you’re faced with a P0455 error code on your troubleshooting device?

The P0455 code is a Diagnostic Trouble Code (DTC) that signifies there’s a serious leak in your car’s EVAP system.

EVAP – Evaporative Emissions System – is an important system in modern vehicles. It comprises a number of components required for its function. The function of this system is to ensure that fuel/gas vapor does not escape into thin air, which could cause fire hazards and environmental pollution.

One of the symptoms of this DTC is a drastic decline in fuel consumption; there are other symptoms too.

What Does P0455 Code Mean?

Technically, the definition of this code is “Evaporative Emissions System – Large Leak Detected.”

If your OBDII scanner pops up this error code, it means a serious leak was detected by the car computer. Every modern car comes with a central computer that scans and reports errors as digital codes known as Diagnostic Trouble Code (DTCs).

You need to know about these codes and what they signify; that way, you would know how to fix most issues with your car without needing a mechanic to charge you for minor works.

Talking about the P0455 DTC and its relation with the Evaporative Emissions System (EVAP). This DTC needs to be cleared as soon as possible so that your car can run smoothly as designed. However, clearing this error means fixing the EVAP component that is causing the detected leak.

Function of the EVAP System

Modern vehicles utilize integrated EVAP systems to trap fuel vapors. These vapors are retained in the canister, before being sent back to the engine through a purge valve and a set of hoses for combustion to occur.

Any damage to the EVAP system components is a big issue that needs to be taken seriously and fixed as early as possible. The components that made up the EVAP system are:

What Causes the P0455 Code to Appear?

Due to the locations of the EVAP components, they are subject to physical damage and excessive wear; they fail easily.

When any of these components fail, which would lead to a leak within the system, your car’s check engine light would come on, and when you troubleshoot, you’d most likely get the P0455 DTC. Below are the common causes:

  • Broken or malfunctioning purge vent valve
  • Faulty system pressure sensor
  • Cracked or missing fuel cap
  • Leaky EVAP hose
  • Fuel tank damage
  • Faulty canister valve
  • Damaged charcoal canister

Symptoms of P0456 DTC

The symptom is the same as that of P0457 and P0456 DTCs because they all talk about leaks within the EVAP.

  • Check Engine Light is On: Apparently, there are many reasons why the check engine icon/light would illuminate. Notwithstanding, a fault in the EVAP system can also trigger the illumination.
  • Increase in Fuel Usage: The moment it appears like your car uses excessive fuel than it has ever done, it could be that one of the EVAP components is badly damage; hence, a huge leaky spot is created and fuel goes out through the spot, as vapors.
  • Gaseous Smell: The EVAP system constrains fuel vapor; so, any leak within the system would cause the vapors to escape and get into the atmosphere, which is unhealthy and poses fire hazard.

How Serious is the P0455 Code?

It is quite a serious one because the technical definition of this code reads: “Evaporative Emissions System – Large Leak Detected.” So, the error means that you’ve got a “Large” leak to deal with – that’s what makes it a serious issue. Nevertheless, you can fix this code by yourself.

How To Fix P0455 Error Code

Here are some safe troubleshooting tips on how to fix the P0455 error code by yourself. However, if it appears you need to replace a leaky component, it is best to engage a mechanic.

1. Scan for Other Codes

You should check if there are other codes detected by your car’s computer, or it’s just the P0456 DTC. If there are other codes, it means you’ve got additional steps to take, but if it’s just the P0455 code, proceed below.

2. Run a Smoke Test

Get a smoke tester and connect it to the EVAP hose’s intake manifold junction; after a while, check if you’re seeing smoke coming out from a spot – if you do, that’s the leaky spot. Fix the leaky spot or change the component.

3. Check The Purge Valve and Hoses

Inspect the vapor purge valve, hoses, and connectors for leaks. Wherever you spot a leak, change the affected component. Also, check to see if the hoses are clogged or blocked – so you can unclog them.

4. Inspect the Entire EVAP System

The fuel tank, gas cap, canister, filter neck, all the components that make up the EVAP system, have all of them checked for leaky spots and physical cracks. Replace any faulty one.

5. Clear the Code

After trying out the steps above, use the OBDII scanner to clear the P90455 DTC and drive on. It would cost you around $200 – $300 to fix the P0455 error. The cost is majorly the cost of replaced components and diagnostics fees.

What More?

The P0455 code means there’s a huge leak in the Evaporative Emissions System that needs to be taken care of. Fixing this issue isn’t too expensive and it’s something you can do on your own.

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