P0455 EVAP System Large Leak Detected

What Is an EVAP System?

Your vehicle’s EVAP system helps reduce your emissions and prevent harmful fuel vapor leaks into the environment. While your vehicle is at rest, vapors are being released from your fuel tank. Without a proper seal, these vapors could easily escape.

Instead, your EVAP system creates a sealed system that channels your fuel vapors through a series of hoses into a charcoal filter canister. Once you start your engine, a purge valve opens and an intake vacuum siphons the vapors into your engine to be burned. So, what does the code P0455 mean? A sensor has noted a large leak somewhere in the system so that a vacuum cannot be created.

While an EVAP system isn’t required to start an engine, it’s an essential protective system. This system protects the environment from harmful emissions, so it’s important to get it repaired as soon as possible. A large leak diagnostic trouble code is related to, and could also cause, these additional trouble codes:

• P0440
• P0441
• P0442
• P0444
• P0445
• And more

Many of these EVAP trouble codes are from a series of sensors that measure different areas for air leaks. A major leak could affect more than one area, causing multiple trouble codes. Inspect the causes and find the solutions of error code P0455 before you clear the code and see if any other code is still present.

What are the Symptoms of a Large Leak?

Because your EVAP system only handles emissions, you won’t likely see any decrease in the overall performance of your vehicle. Over time, you may notice a slight decrease in fuel economy. When stored in a garage or closed space, you may smell fuel vapors. The worst symptom, however, is increased emissions polluting your environment.

What are the Causes of Error Code P0455?

Because the entire fuel and EVAP system need to be completely sealed in order for the EVAP system to work effectively, even a slight hole or crack in a single component could trigger the error code. You’ll need to carefully inspect your entire EVAP system:

• Fuel cap
• Fuel tank and filler neck
• Charcoal canister
• EVAP hoses
• EVAP/Canister vent valve solenoid
• EVAP/Canister purge valve

A common cause is a missing or loose gas cap. This easy-to-fix solution could be all you need to restore your EVAP system. However, minor tears, or rotten spots in your EVAP hose could also be the culprit.

Your filter canister may also be cracked. This can happen if you attempt to pressurize your EVAP system with air, so don’t use this as a strategy for finding the air leak. Another component that could be damaged is your purge valve solenoid or canister vent valve solenoid. Over time, these part may wear out.

Repair Solutions

Whether you’ve found the cause or not, replacing the damaged component in your EVAP system should restore the seal and keep your fuel vapors contained. Check the easiest solution first by tightening or replacing your fuel cap. After you’ve cleared your error code, code P0455 will return if this wasn’t the source of the air leak.

Next, replacing a section of hose is the next most common issue. While general use shouldn’t damage your EVAP hose, this material can be affected by severe weather or temperature. Finally, if these solutions aren’t effective at solving your error code problem, test the vent valve solenoid and purge valve solenoid. Replace the failing component and clear the trouble codes (proper procedure requires a code reader or scan tool with such a capability).You can get the parts you need at your local AutoZone Store.
If the job is too big for you, seek out one of our Preferred Shops to help you do the job.