The evaporative emission control system is also known as the EVAP system. It is usually installed in the modern vehicle models. The EVAP system helps to lower the emission of exhaust gases and prevents fuel vapors from being released into the atmosphere. The P0455 code indicates an issue with the EVAP system.
The powertrain control module (PCM) of your vehicle continuously monitors the performance of the EVAP system. When it monitors a very large evaporative emission control leak, it stores the diagnostic trouble code (DTC) P0455. This article mainly explains the P0455 code meaning, causes, symptoms, and how to fix it.
P0455 Code Definition
The P0455 code stands for “Evaporative Emission Control System Large Leak Detected.”
What does the P0455 Code Mean?
The P0455 code indicates that the powertrain control module (PCM) of your vehicle notices a large leak in the evaporative emissions (EVAP) control system.
The latest vehicle models have an integrated EVAP system. This system helps to reduce the exhaust emissions. It collects the fuel vapors that would otherwise be released from the fuel system into the environment. These vapors are then stored in an EVAP canister before being returned to the engine’s intake through a purge valve and hoses.
The PCM of your vehicle controls the operation of the vent control valve. This valve permits the air to flow through the charcoal canister. The flow of air allows the purging of fuel vapors into the air intake of the engine for combustion.
The EVAP system contains a purge valve that controls the fuel vapor’s flow from the charcoal canister to the engine’s air intake. As your engine starts operating, the vent control valve remains open while the purge volume control valve remains closed.
The PCM opens the purge volume control valve when it gets a command to discharge the stored fuel vapors from the charcoal canister. When the purge volume control valve opens, it transfers the collected fuel vapors toward the combustion chamber.
When the PCM monitors a large leak in the EVAP system, it stores a trouble code P0455.
Symptoms of the P0455 Code
Trouble code P0455 is entirely emissions-related; hence your vehicle will be unable to notice any further symptoms other than the illumination of a check engine light.
Below are the most common symptoms of the P0455 code:
- Fuel Smell
- Check engine light illumination.
- Poor fuel economy
- Hissing noise while the engine is running
- In some conditions, a large EVAP system leak may also lead to hard engine starting conditions.
Read More: Symptoms and Causes of P0453
Causes of the P0455 Code
The most common causes of the P0455 trouble code are as follows:
- Leaked or opened gas cap
- Cracked or leaked EVAP hoses
- Loose gas cap
- Faulty EVAP vent solenoid
- Faulty or cracked charcoal canister
- Faulty fuel tank pressure sensor
- Fault in gas tank fuel filler neck
- Faulty purge control valve
- Cracked or leaked fuel tank
- Fault in PCM
- Vent valve solenoid failure
Read More: Symptoms and Causes of P0017
How to diagnose 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) Test EVAP System Components
You need to properly check the connectors and wires connected to the EVAP system of your vehicle. Test the performance of different EVAP system components (such as the purge valve and vent control valve) by using a multimeter.
5) 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.
6) 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.
7) Check the Fuel Tank Pressure Sensor
Now, properly examine the fuel tank pressure sensor of your vehicle. You can check the pressure sensor with the help of a digital multimeter by following the owner’s manual instructions.
8) Clear the Codes
After making the necessary repairs, clear the P0455 code by using the OBD2 scanner. After clearing the codes, perform a test drive. If the code returns, contact a professional mechanic.
Common Diagnostic Mistakes of the P0455 Code
- Replacing the costly parts without inspecting the system thoroughly
- Installing the new parts without testing them. Sometimes the new parts can be defective.
- Overlooking other stored codes and just focusing on the P0455 code
- Ignoring the inspection of the gas cap
- Not clearing the codes after repairing the issues.
- Not using suitable tools while diagnosing the P0455 code
- Overlooking wiring and electrical issues
- Skipping the smoke test
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.
What repairs can fix the P0455 Code?
To fix P0455 code, you need to repair or replace one or more of the following parts:
- Replace or repair the damaged or leaked gas cap
- Replace or repair the faulty vent valve solenoid
- Check the fuel filler neck, and replace it in case of any damage
- Repair the damaged fuel tank
- Replace the faulty fuel tank pressure sensor
- Repair the issues related to the hoses.
- Repair the faulty connections and damaged wires
- Replace the bad purge valve
- Replace the bad purge volume control valve
- Repair the damaged EVAP lines
P0455 Code Repair Cost
The repair cost of the P0455 code varies according to the repair type and the vehicle model. The table given below shows the estimated repair cost of the P0455 code according to the repair of each part:
| Part | Cost |
|---|---|
| Vacuum Hose Replacement | 5$ to 60$ |
| EVAP Vent Control Valve | $50 to $210 |
| Gas Cap replacement | $18 to $70 |
| EVAP line repair | $20 to $120 |
How to Prevent P0455 Code?
- Ensure regular maintenance of your EVAP system according to the manufacturer’s instructions.
- Fix the issues related to the EVAP system promptly.
- Avoid overfilling the fuel tank
- Make sure your gas cap is on tight after adding fuel to the fuel tank
- Avoid to add fuel in your fuel tank when it is hot
- Replace and clean your fuel filter regularly
- It is necessary to check the condition of the gas cap after filling the fuel tank. If the gas cap is damaged, it is recommended to replace it to prevent the P0455 code from triggering.
FAQ Section
What causes the P0455 code?
- Loose gas cap
- Cracks or breaks in EVAP hoses
- The EVAP vent solenoid is broken or jammed open.
- Faulty or cracked charcoal EVAP canister
- A gas cap that is faulty or defective
- Bad fuel tank pressure sensor
- Fault in gas tank fuel filler neck
- EVAP purge valve failure
- Fault in PCM
- Vent valve solenoid failure
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.
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 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.