What is P0455 DTC? Common Symptoms, Causes, and Solution
EVAP is an important component of your vehicle that prevents the evaporation of fuel particles into the atmosphere. However, the gas cap or other components can become faulty with time, allowing the fuel particles to evaporate. In this case, P0455 DTC will occur.
The following are the key takeaways from this article:
P0455 is a low to intermediate intensity DTC indicating a leak in the EVAP system.
The common causes of this DTC include a loosened fuel cap, defected valve control solenoid, and defected carbon canister.
The common symptoms of this DTC include a decrease in fuel mileage, fuel smell from turning off the vehicle, rough idle engine, and check engine light.
The solutions of this DTC include replacing the faulty EVAP, gas cap, solenoid, and rubber lining around the solenoid.
This DTC can range from $20 in case of a faulty gas cap to $600 to replace the faulty gas tank/EVAP.
Introduction
Gasoline is a highly volatile substance that can evaporate at normal temperatures. Automotive manufacturers know this fact and have introduced EVAP systems in vehicles that comprise vent control valve mechanisms (1). The vent control valve usually opens when the engine is on, and the purge control valve is usually closed. However, ECM opens the purge control valve when it is ready to purge the fuel vapors into the cylinder from the charcoal canister. Along with the control of the purge control valve, ECM also performs leak tests to analyze the working of EVAP (4). During the leak test, the vehicle is turned off, and the ECM closes the vent control to seal the EVAP system. The EVAP needs to maintain a specific pressure to illustrate proper seal condition.
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If EVAP does not maintain the particular pressure, then ECM recognizes a leak condition. The DTC, in this case, would be P0455 which indicates a large leak in the EVAP system.
This article will shed light on the causes, symptoms, and possible solutions of P0455 DTC.
How to Read P0455 DTC
The following table has read every character of P0455 DTC (2):
Number of Character
Specific Character
What does it Signify
First
P
The problem lies within the powertrain part of the vehicle. This means that the engine, transmission, or fuel system can malfunction.
Second
0
This means that the code is standardized, so the SAE manual can be used further to interpret the code instead of the instruction manual.
Third
4
This number illustrates that the problem lies within the vehicle’s emission system.
Fourth and Fifth
55
The specific fault index is 55, indicating system gross leak evaporative system malfunction.
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P0455 means that the DTC code is an SAE-standardized code, and the problem lies within the vehicle’s emission system. Furthermore, the third, fourth, and fifth characters illustrate gross leak evaporative system malfunction in the vehicle.
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Causes of P0455 DTC
Loosened Fuel Cap
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The major cause of the engine code P0455 is the loose fuel cap. Due to the loose fuel cap, dirt and germs will enter the engine system, clogging the filter.
Thus, it badly affects the performance of the engine. Due to the dirty engine, the fuel injectors will get damaged, and the cylinders will not be supplied with fuel on time. There are chances that misfires can occur in the engine as the air-to-fuel ratio will be disturbed because of the irregular supply of fuel from the injector (3). Thus, the revolution per minute of the vehicle will be immediately reduced, the car will start shaking, and acceleration will slow down. Other than it, due to the space in the cap, the fuel vapors will find enough space to escape into the air (1). These vapors will create problems for the engine’s emission system, and the fuel vapors are released into the air, producing the fuel smell in the environment. Hence, the engine check light is turned on to indicate to avoid accidents.
Defected Vent Control Valve
The other major cause of the engine code P0455 is the defective vent control valves. The vent control valves play an essential role in the emission system. The purpose of the vent control valve is to control the flow of air through the charcoal canister.
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The vehicle’s electronic control module handles the vent control valve. The valve remains open and immediately closes when the ECU system detects the leakage in the evaporation system (4). Sometimes due to corrosion in the vent control valve, dirt will get deposited into the valve if it fails to close. As a result, the performance of the engine is impacted. Due to the defective vent control valve, the illuminated engine light indicates issues with the evaporation emission system.
Defected Purge Control Valve and Carbon Canister
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The other major reason for the engine code P0455 is the defective purge control valve. The purge control valve is present in the vacuum system, and the purpose of the purge valve is to flow air into the engine.
Thus, due to the damaged purge control valve, the exact amount of air will not be predicted by the engine’s electronic control unit. As a result, an unbalanced amount of air will enter the engine system, which disturbs the air-to-fuel ratio. It impacts the combustion process, and the engine will fail to accelerate, and noises from the engine will be observed (2).
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Furthermore, the other major symptom of the engine code P0455 is the defective carbon canisters. The carbon canisters play a vital role in the engine system. The purpose of the carbon canister is to store the harmful substances that are waste products of fuel and do not allow to release into the air.
Due to the damaged carbon canister, these harmful fuel vapors will be released into the air, and the fuel smell will spread into the environment (3). Thus, the engine check light will illuminate due to the increased emission process, indicating the error code P0455.
Symptoms of P0455 DTC
Decreased Fuel Efficiency
The major symptom of the engine code P0455 is that the engine will start consuming a large amount of fuel than the requirement. This indicates that fuel is being evaporated due to the defective engine parts.
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This symptom indicates the problem of the loosened fuel cap. Thus due to the loosened cap, the fuel vapors start to evaporate in the air, and a large amount of fuel is evaporated instead of reaching the combustion chamber (1). Thus, a large amount of fuel is utilized due to the evaporation of fuel, which indicates the issue with the evaporation system and engine code P0455.
Rough and Idle Engine Performance
The other major symptom of the engine code P0455 is the rough and idle performance of the engine. The engine’s performance becomes idle and weak due to the damaged components of the engine.
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Due to the defective vent control valves, an unbalance amount of air is entered the combustion chamber, which becomes the hurdle in the ignition of the spark (2). Thus, due to the disturbed air-to-fuel ratio, the spark’s ignition is delayed, and the acceleration process is slowed. As a result, the engine becomes idle and produces noisy sounds.
Fuel Odor
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The fuel odor is another symptom indicating the issue with the engine code P0455. Due to the loosened gas gap and defective charcoal canister, the fuel vapors are directly emitted into the air, spreading the fuel smell.
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Thus, this symptom indicates an issue with the car emission system, and the engine’s performance is becoming idle.
Solutions of P0455 DTC
Following are a few common solutions of P0455 DTC:
Replace the Gas Cap
A defective gas cap is the most common problem causing DTC P0455. The gas cap is located inside the gas lid that can be placed at the front or back of the car. In normal sedans, it is placed at the right or left backside of the car. While in cars such as Porsche, the gas cap can be located at the front right or left side (2). The gas cap has an ‘O-seal’ that helps tighten it. With time, this ‘O-seal’ wears out, resulting in a loose gas cap. You can check the ‘O-seal’ visually or check the tightening of the gas cap yourself. If the gas cap is loose, it is better to order it from online platforms (5). You can consult the instruction manual to further check the specifications of the gas cap before ordering.
Replace the Faulty EVAP Line
Another solution for DTC P0455 is to replace the faulty EVAP line. These lines can deteriorate due to vibration and engine heat, due to which the rubber lining will collapse or fall off the vacuum system. This impacts not only the vacuum but also the connection with the solenoid. So, it is recommended to check the rubber lining for cracks and tears up to the vacuum control solenoid (4). The solenoid’s location can be detected using the vehicle’s instruction manual. Usually, it is mounted near the fender or the vehicle’s intake manifold. The damaged rubber lining can be replaced at home, but ensure that you have ordered the rubber lining according to the manufacturer’s specifications.
Replace the Faulty Valve Control Solenoid
Another solution for DTC P0455 is to replace the faulty control valve. A failed solenoid would not close the plunger, resulting in the evaporation of the gasoline fumes. The solenoid can be tested by grounding it and supplying a 12V power supply (2). A click sound in the solenoid illustrates that it is working fine. On the other hand, a solenoid not producing a click sound has gone bad and needs replacement. Replacing a solenoid is difficult and might require professional supervision. Therefore, it is recommended to take the car to a professional mechanic to get the faulty solenoid replaced.
Reset the DTC and Test Drive
The most common solution for this DTC is to reset the DTC and test drive the vehicle. In some cases, ECU sends the wrong code due to an error. For example, suppose you are not observing any signs of fuel evaporation. In that case, it is recommended to reset the DTC by connecting a hand-code reader (3). But, first, test drives the vehicle for a few miles to ensure that the DTC/warning light does not occur again.
Common Cost to Resolve the Issue
The following table illustrates the cost required to resolve P0455 DTC:
Common Issues
Critical Level
Cost Required to Resolve the Issue
Damaged Tank Filler Cap
Low: You can drive for long distances with this problem. However, there will be a decrease in the fuel economy as the fuel will evaporate when the cap is loose.
$20-70, depending upon the model of the vehicle, to replace the fuel cap.
Damaged Tank
Intermediate: It is risky to drive with a damaged tank, as leaking fuel can cause a fire in the vehicle.
$400-600 to replace the damaged fuel tank.
EVAP Canister
Low: There are no driving risks, but the car would not pass the emission tests with damaged components.
$150-400 to replace the faulty EVAP Canister.
Carbon Canisters
Low: You can drive for long distances with this problem. However, there will be a decrease in the fuel economy as the fuel will evaporate when carbon canisters are damaged.
$150-600 to replace the carbon canister.
Labor Cost
–
$20-200 to replace the faulty components.
Conclusion
To conclude, P0455 is a low-intensity warning indicating a leak in the EVAP. The check engine light indicates this DTC, decreased fuel mileage, and fuel smell from the turned-off vehicle. The OBDII module will sense the problem and turn on the check engine light so the driver knows about the malfunction. Although you can drive your vehicle for an intermediate distance, the evaporative valve might malfunction to reduce your fuel mileage.
It is easy to check the gas cap condition. You can always open the fuel lid to rotate the gas cap. If the gas cap loosens while tightening, it is a clear sign that the gas cap is faulty. Similarly, you can visually analyze the ‘O-seal’ below the gas cap. If the ‘O-seal’ has worn out, it is time to replace the faulty gas cap.
The position of the valve control solenoid can differ depending on your vehicle’s model and manufacturer. It can also be placed at the side of the fender or between the intake manifold. You can check the solenoid by connecting it to a 12V power source. If the solenoid makes a click sound, it works correctly, and vice versa.
A decrease in fuel mileage is only sometimes a sign of defective EVAP. The fuel mileage can also decrease due to different engine fault codes such as P0100, P0153, P0290, etc. These fault codes indicate a problem in the engine components, turbocharger, etc. But suppose you are smelling fuel from a turned-off vehicle. In that case, it is a sign that the EVAP system is malfunctioning and the fuel fumes are evaporating.
