P0455 – Evaporative Emission (EVAP) System Leak Detected


The gas cap is held responsible for a P0455 code flashing on the car’s computer once the scan tool is attached to determine the cause. We try our best to repair or replace gas caps which isn’t the root cause of the issue. The problem is something else, and a mechanic inspection would help you determine the reasons behind it. Let us unveil the underlying reasons, diagnosis, and ways to fix the p0455 engine code.

What Does Error Code P0455 Mean?

The P0455 code means that a large leak has been suspected in the Evaporation Emission System present in the car. The computer would flash the leak, which signifies a leak in the car’s emission system. Even the branded car models flash this error, including the Chevrolet, Ford, Dodge, Jeep, and Nissan. Note that different manufacturers have a different definition related to the P0455 code so ensure that the manufacturer’s manual or database is thoroughly checked for inspection.

What Causes Leak in the Evaporation Emission System?

The leak doesn’t occur due to a single reason, as many of them are responsible for it. At times it’s the missing fuel filler or isn’t installed properly. Sometimes, the top of the filler neck is damaged and needs attention. Hose leaks are another prominent leak cause in the Evaporation Emission System. As time goes, the hose starts aging, especially the large connecting hose attached to the filler on the tank. The cars with a charcoal filter on their evaporative systems need to be checked for cracks, damages, or leaks. Sometimes it’s the leak in the fuel tank or gasket where the fuel level sensor, pressure sensor, and fuel pick connect with each other. The code reveals that the leak is large, but it is too small, so get the p0455 evap code diagnosed from the qualified technician.

What are the Signs of the P0455 Code?

Illuminating check engine light

An illuminating check engine light generally accompanies a P0455 code. You would also suspect a fuel smell in the tank or filler area. Sometimes the bad odour comes from the evaporative lines of the engine intake system.

What Not to Do While Diagnosing a P0455 Evap Error?

Not following proper procedure while diagnosing the P0455 error code is one of the biggest mistakes. Investing in a car part without having an accurate estimate of its cost is futile. A fuel cap generally costs $30, while replacing the evaporation emission system is quite costly. Save money by getting the estimates of the evaporation emission system cost, watching the DIY videos, and fixing the issues yourself.

How Severe is the P0455 Code?

P0455 code won’t become an impediment in the working of your car. If the fuel odors are strong or have leaks, taking them to a qualified mechanic is the best action. You would end up adding more fuel to the cars when the leaks are suspected. In case there are no issues, a reset is performed, and the car is tested again. While testing, the quantity of fuel should be between 1/4 to ¾. Sometimes the OBD system reset will resolve the issues in no time.

What are Some of the Ways to Fix a P0455 Code?

  1. Try a gas cap replacement or tighten the seal.
  2. Get a new fuel filler neck in case it’s damaged or has any other issue; you can seal it using the cap.
  3. Fix hose issues, if any.

Significant Considerations to be Kept in Mind

  • Once the vehicle has covered 100,000 miles, the sensor problems start or stress the drive train.
  • Despite an illuminating check engine light, the car runs normally. After resetting it, the issues might pop up again.
  • Diagnose code p0455 before performing replacements to fix the issues.

How Much Does Fixing a P0455 Code Cost?

Multiple reasons can be held responsible for a P0455 code. Diagnosis from the mechanic can determine the cause that triggered the code. A qualified mechanic would charge $114.99 that could burn a hole in your pocket. You can save money with a new Evaporative Emission System and watch the DIY videos to fix the problem.

The Bottom Line

Cracks or leaks in the Evaporative Emission Systems mustn’t be taken lightly. A qualified mechanic must be consulted or carry out a step-by-step replacement process to fix the issues.

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