P0455 Code Symptoms and Causes | How to Fix P0455 Code?

Every vehicle has the Diagnostic Trouble Code (DTC) codes that are generated by the vehicle’s computer when it faces any problem with any of its parts. P0455 code triggers when your powertrain control module (PCM) observes a large gasoline vapor leak or absence of purge flow in the evaporative emission (EVAP) control system of your car. This article mainly explains the P0455 code symptoms and causes.

What does the P0455 Code Mean?

The P0455 code warns that the powertrain control module of your vehicle notices a large fuel leakage in your EVAP control system. 

P0455 code

The evaporation system of your car helps in stopping the fuel vapors from mixing with the outer atmosphere.

Modern automobiles have an integrated evaporative emission system to collect the typical evaporation of the fuel vapors. These vapors are then collected in an EVAP canister before being returned to the engine’s intake through a purge valve and hoses.

The engine vacuum is passed through the canister to purge solenoids to move air into the canister. The collected fuel vapors in the intake manifold are transferred towards the combustion chamber as part of the fuel-air mixture.

The trouble code P0455 acts as a leakage indicator. This is indicative of a leak within Your EVAP system. This leak is identified by aberrant pressure sensor readings, which are then read by the PCM. The system generates a P0455 code as a result of the fluctuating readings, and the check engine light illuminates.

Symptoms of the P0455 Code

Trouble code P0455 is entirely emissions-related; hence your vehicle will be unable to display any further symptoms other than the illumination of a check engine light.

Below are the most common symptoms of the P0455 code:

  1. A strong odor of gasoline fuel at the filling or tank region.
  2. Check engine light illumination.
  3. The odor might potentially go from the evaporative pipes to the engine intake system.

Read More: Symptoms and Causes of P0453

Causes of the P0455 Code

The most prevalent causes of the P0455 trouble code are as follows:

  1. The gas cap is lost, open, or poorly fastened.
  2. Cracks, leaks, or breaks in EVAP hoses
  3. The EVAP vent solenoid is broken or jammed open.
  4. Faulty or cracked charcoal EVAP canister
  5. A gas cap that is faulty or defective
  6. System pressure sensor failure
  7. Fault in gas tank fuel filler neck
  8. EVAP purge valve failure
  9. Fuel tank crack
  10. Fault in PCM
  11. Vent valve solenoid failure

Read More: Symptoms and Causes of P0017

How to Fix the P0455 Code

Follow the below-given steps to diagnose or repair the P0455 trouble code:

1) Check for Additional Codes

Always check if there are some additional trouble codes before starting the diagnostics. For this process, use an OBD-II scanner. Run an in-depth scan to find all the existing codes.  

2) Examine the Gas Cap

The loose or broken gas cap of your fuel tank is one of the most common causes of the P0455 code. Hence, thoroughly inspecting your vehicle’s gas cap is a great spot to begin the diagnostic procedure.

Ensure the tightness of the gas cap. If the error occurs due to a damaged or broken gas cap, replace your gas cap with a cap of OEM equivalency. Before a test drive, don’t forget to clear the trouble code using an OBD-II scanner.

3) Examine the Hoses and Filler Neck

Examine all connected hoses for signs of wear if the DTC P0455 appears again. If this code returns, you should now inspect all hoses connected to the EVAP system for signs of deterioration. The occurrence of visible flaws will need repair. Similarly, the EVAP canister and gasoline tank filler neck of the vehicle should be examined.

4) Perform Smoke Test

If the code appears again and you have not reached the root cause, then the smoke test is the best option to find leaks and hidden issues in the system. Put the shop-grade smoke machine into the evaporative emission system of your vehicle. You can now notice the smoke from any tinny leakage as well.

5) Carry out System Functionality Tests

Now, after the smoke test, if no leakage is detected, the complete system functionality test should be conducted using the bidirectional scanning tool. Typically, such testing will confirm the existence of a defective purge valve or solenoid.

6) Check the Pressure Sensor

Now, if you can’t find a noticeable fault, then there may be an issue with the pressure sensor. You can check the pressure sensor with the help of a digital multimeter by following the steps mentioned in the user manual.

Common diagnostic mistakes of the P0455 Code

  1. The most common diagnostic mistake for trouble code P0455 is to start a detailed diagnosis.
  2. To replace the new part without checking them. Sometimes the new parts can be defective.
  3. This error code usually triggers when you do not shut off the car when filling up at a gas station or when there is a problem with the gas cap.  

How serious is the P0455 code?

Commonly, the P0455 code is not considered a serious trouble code. This code is not too harmful and does not create any hindrance while driving. This code represents a large leak in your system that may create an excessive loss and consumption of fuel that will result in spending some extra money on fuel.

It is critical to understand that code P0455 deals with emissions, and the vehicle with this code may fail the emission test. Tests of this nature often involve scanning a vehicle’s OBD-II system for active emissions codes. You can’t achieve the best efficiency of your vehicle with this code.   

How Simple Is It to diagnose a P0455 Code?

The OBD2 scanner is the proper tool for the diagnostic of leaks. Then record all the codes and freeze frame data. Now they will reset the code and notice if, after a test drive, the code disappears or not.

This test requires a fuel level of 15 to 85 percent in most vehicles. If the fault code appears again, the mechanic should analyze your car and look for the source of the leak.

Additionally, a smoke test can be conducted for confirmation if no obvious leaks are found. Your mechanic will use a series of smoke tests to detect the leaks in the vacuum hose. This test tells you about the leak in the vacuum system. If you couldn’t find any leak, then the issue is with the sensor. To check the issue with the sensor, examine the sensor using the manufacturer’s instruction book.

P0455 Code Repair Cost

The repair cost of the P0455 code varies according to the repair type and the vehicle model. The below-given table shows the estimated repair cost of the P0455 code according to the repair of each part:

Vacuum Hose Replacement5$ to 60$
EVAP Vent Control Valve$50 to $210
Gas Cap replacement$18 to $70

FAQ Section

What repairs can fix the P0455 code?

Here are some important fixes of P0455:

  • If the gas cap does not tighten or seal, replace it
  • Replace or repair the faulty vent valve solenoid
  • Check the fuel filler neck, and replace it in case of any damage
  • The damaged fuel tank must be repaired or replaced
  • Repair the issues related to the hoses.
  • Replace the malfunctioning system pressure sensor
  • Repairing faulty connections and wirings

What causes the P0455 code?

  1. Loose gas cap
  2. Cracks or breaks in EVAP hoses
  3. The EVAP vent solenoid is broken or jammed open.
  4. Faulty or cracked charcoal EVAP canister
  5. A gas cap that is faulty or defective
  6. System pressure sensor failure
  7. Fault in gas tank fuel filler neck
  8. EVAP purge valve failure
  9. Fuel tank crack
  10. Fault in PCM
  11. Vent valve solenoid failure

How to clear code P0455?

To clear the P0455 code, you should use an OBD2 scanner. Just connect the diagnostic scanner, clear the codes, and take your car for a test drive.

Can I drive with code P0455?

Yes, you can drive your vehicle with the P0455 trouble code unless the smell of fumes is very strong or there is a serious fuel leak. In such a condition, you should contact a mechanic to fix this code and prevent your car from severe damage.  

Can I drive with an EVAP leak?

Yes, you can drive your vehicle safely. The main function of the evaporative emission control system is to stop fuel vapors from escaping the fuel tank system into the air to control greenhouse gas emissions.

What would cause a large EVAP leak?

The loose or missing gas cap is one of the most common causes of EVAP leaks. Restore your EVAP system with this easy-to-repair solution. However, small cracks or rotten spots in the EVAP hose may also lead to lead.  

Can an exhaust leak cause a P0455 code?

The code P0455 indicates a large leak in your vehicle’s EVAP system, and fuel vapors are not being captured and retained as expected.

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