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P0457 OBD-II Trouble Code: Evaporative Emission Control System Leak Detected

Check Engine Light

Diagnostic Trouble Code (DTC): P0457

P0457 code definition

When the PCM (powertrain control module) detects a leak in the evaporative emission control system, the P0457 code will be stored and the Check Engine Light will be illuminated.

What the P0457 code means

The evaporative emission system is designed to keep fuel vapor from leaking out into the surrounding air and causing pollution. If there’s a vacuum leak in this system, a P0455, P0456, and/or P0457 code will be detected and stored by the PCM. These codes are very similar, but they differ in how severe the leak is. The P0457 code refers to the most severe emissions leak, while the P0455 code refers to a lesser leak.

What causes the P0457 code?

Because the P0457 code is only stored when there is a large leak, you can rule out a number of smaller problems that might result in a P0455 or a P0456 code. In most cases, a P0457 code is stored due to:

Because this system is protected from the elements, a P0457 code will generally not be caused by weathering or aging of system parts and instruments.

What are the symptoms of the P0457 code?

In general, the vehicle’s performance and drivability will not be affected by a P0457, though in some cases you may notice a decrease in fuel efficiency if the fuel leak is large enough. In most instances, though, the only indicator that the driver or vehicle owner will get will be the illuminated Check Engine Light.

How does a mechanic diagnose the P0457 code?

Because the P0457 code doesn’t generally present any symptoms other than an illuminated Check Engine Light, it’s necessary for a mechanic to use an OBD-II scanner to detect what kind of code is causing the light to turn on. Once the P0457 code is identified, the mechanic will begin a visual inspection, starting with the gas cap.

If the gas cap is missing, worn, cracked, or has some foreign object in the threads preventing it from getting a good seal, the mechanic will replace it, clear the code, and test drive the car to ensure that the code doesn’t get stored again. If the issue is not with the gas cap, the mechanic will move on to inspect the rest of the evaporative emission control system.

Common mistakes when diagnosing the P0457 code

Sometimes this problem occurs simply because the gas cap isn’t tightened properly, which can make the vehicle owner and/or mechanic believe that some component of the evaporative emission control system needs to be replaced.

How serious is the P0457 code?

The P0457 code is the most severe code related to leaks in the evaporative emission control system. It can increase your vehicle’s fuel emissions while decreasing your fuel economy. Depending on the problem, it could lead to even larger fuel leaks later on, which could be more expensive and could cripple your vehicle until you get them resolved.

What repairs can fix the P0457 code?

The most common repair for this code is to either ensure that the gas cap is tightened properly or to replace it. Other repairs include:

Additional comments for consideration regarding the P0457 code

The P0457 code should be fairly simple to address and resolve. It’s important to do a thorough visual inspection, though, as missing a problem with the gas cap could result in replacing perfectly good components of the evaporative emission control system, resulting in a more expensive repair than necessary.

Need help with a P0457 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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