Error P0457 – how to fix?

Diagnostic Trouble Code (DTC): P0457

Code definition P0457

When the PCM (Powertrain Control Module) detects a leak in the evaporative emission control system, a code P0457 is stored and the Check Engine light illuminates.

What does the code P0457 mean

The evaporative emission system is designed to prevent fuel vapors from escaping into the surrounding air and causing pollution. If there is a vacuum leak in this system, code P0455, P0456, and / or P0457 will be detected and stored by the PCM. These codes are very similar but vary in severity of the leak. The P0457 code refers to the most severe emission leak, while the P0455 code refers to the minor leak.

What causes the code P0457?

Since P0457 is only stored when there is a large leak, many minor problems can be ruled out that could cause P0455 or P0456. In most cases, the P0457 code is stored because of:

• Missing, cracked or loose fuel cap.
• Cracked or rotten hose
• Cracked vacuum cleaner container
• As this system is protected from the elements, the P0457 code is not usually caused by the aging of the system parts and instrumentation.

What are the symptoms of the P0457 code?

In general, P0457 will not be affected by vehicle performance and driveability, although in some cases a decrease in fuel efficiency may be noticed if the fuel leakage is large enough. In most cases, however, the only indicator that the driver or owner of the vehicle will get will be the Check Engine light illuminating.

How can a mechanic diagnose the P0457 code?

Since the P0457 code usually shows no symptoms other than the Check Engine light being on, it is imperative that the mechanic use an OBD-II scanner to detect what type of code is causing the light to come on. Once the P0457 code is identified, the mechanic will begin a visual inspection starting with the fuel cap.

If the fuel cap is missing, worn, cracked, or has any foreign objects in the threads that prevent a good seal, a mechanic will replace it, clear the code and test the car to make sure the code is not stored again. If the problem is not a fuel cap, the mechanic will continue to check the rest of the Evaporative Emission Control System.

The most common errors when diagnosing the P0457 code

Sometimes this problem occurs simply because the fuel cap is not properly tightened, which can lead the vehicle owner and / or mechanic to believe that some part of the evaporative emissions control system needs to be replaced.

How serious is the P0457 code?

The P0457 code is the most serious leakage code associated with the Evaporative Emission Control System. This can increase your vehicle’s emissions and reduce fuel consumption. Depending on the problem, this can lead to even more fuel leaks on the road, which can be more costly and can paralyze the vehicle pending repair.

What repairs can remove the P0457 code?

The most common repair for this code is to make sure the fuel cap is tight or to replace it. Other repairs include:

1. Replace one or more evaporative emission control system vacuum hoses.
2. Make sure the intake manifold connection is tight and free from cracks, and replace if damaged.
3. Replace the charcoal element if it shows signs of cracking.

Additional notes regarding code P0457

The P0457 code should be fairly simple to address and solve. It is important, however, to make a careful visual inspection because overlooking a fuel cap problem could result in the replacement of perfectly good components in the evaporative emission control system, resulting in a more expensive repair than necessary.