P0457 Code (Symptoms, Causes, and Fixes)

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When you notice a drop in the performance of your car, one of the foremost things you’d likely do is use an OBDII scanner to troubleshoot the car computer to find out what could be the cause. But portable troubleshooting devices display errors in codes, which can be pretty confusing.

If you got the P0457 code on your troubleshooting device, it signifies that your car’s Evaporative Emission (EVAP) Control System is not functioning as expected.

Actually, issues with the EVAP system can trigger P0455, P0456, or P0457 error codes. This article explains the causes, symptoms, and fixes to apply when faced with these codes.

What Does the P0457 Code Signify?

P0457 is a Diagnostic Trouble Code (DTC) that indicates there’s an issue with your car’s EVAP system. The technical description of this error code is Evaporative Emission System Leak Detected (Fuel Cap Loose/Off).

When you get this error code on your troubleshooting device, it means your car’s computer – the Powertrain Control Module (PCM) – detected a huge leak in the EVAP system. Typically, the leak is caused due to loose or broken fuel cap; there are other reasons too.

What is the EVAP System?

The Evaporative Emission Control System, shortened as EVAP, is crucial in modern cars. Its function is to prevent fuel vapor from escaping into the atmosphere.

Apparently, we all understand that fuel can evaporate if not covered. The EVAP system typically comprises the following components:

  • Fuel tank
  • The gas cap
  • A charcoal canister
  • Pressure sensors
  • Purge valve
  • Vent valve
  • Hoses and lines that connect the components

While all these components are pretty important, the charcoal canister is practically the major component of the EVAP system. The canister stores fuel vapors when the engine is off.

In contrast, when the engine is running, the purge valve is engaged by the PCM to allow fuel vapors to be drawn into the engine for combustion to take place.

Symptoms of the P0457 Code

If you start noticing any of these symptoms, you’d most definitely get the P0457 code when you check your car with an OBD2 scanner.

  • You always smell fuel when close to the car
  • Check engine light is on
  • Fuel finishes faster

These are the three commonest symptoms that depict your car would throw up the P0457 code when troubleshoot-ed.

Causes of P0457 Error Code

Hereunder are the commonest reasons why your car is throwing a P0457 error code.

1. Serious Fuel Leak

Your vehicle would output this error code when checked with an OBDII scanner if the central computer detects a serious fuel leak.

The leak could be due to a crack on the delivery lines or host; it could also occur if you forget to put back the fuel cap after a refill.

2. Physically Damaged Fuel Cap

When there’s a crack on the fuel cap, it would cause fuel to evaporate; thus, leading to the P0457 error code showing up when you trouble the car’s computer.

3. Rot on the Lines Due to Aging

Over time, regular exposure to the components of the EVP system or sheer age can cause the hose’s material to loosen, crack, or rot. When this happens, you’d get the P0457 code when you troubleshoot.

How to Fix the P0457 Error Code

There are a couple of ways to fix this error code without having to involve a technician. However, when you try out these fixes and the code persists, get a technician to take it up from there.

1. Troubleshoot for Other Codes

The first thing to check when you get this DTC is to check for other DTCs; are there other error codes that appeared with the code? That way, you can know exactly where to look out for possible issues with your vehicle.

2. Check the Fuel/Gas Cap

If the fuel/gas cap is loosened, crack, or missing, that’s the cause. So, simply tighten the cap, replace it (if broken), or find where it fell off (if missing). once this is done, clear the code and you’re good to go.

3. Inspect the EVAP System

When you check the fuel cap and it’s looking all good, then you should inspect other components of the EVAP system, which includes the vacuum hose, lines, and charcoal canister.

If there’s a crack or physical damage on any of these components, get the component replaced and clear the code. 

4. Check For Leaks

The P0457 code main indicates there’s a leak somewhere in the EVAP system; so, you should physically check for the leaky component and fix it immediately. There are two ways to look out for leaks in the EVAP system:

First, hook a smoke tester inline at the EVAP hose’s intake manifold junction; you should be seeing smoke billowing from the leaky spot – take note of the spot and fix the issue. Secondly, you could use a vacuum tester to carry out the same test.

What More?

The P0457 code simply indicates a leak in the EVAP system; once you can detect where the leak is coming from and replace the bad component(s), this error would be cleared. It is not really a severe situation to be worried about. Mostly, it’s just your fuel cap that you forget to tighten after refilling fuel.

However, if the error code persists, or other error codes that appeared alongside, get a professional auto technician to handle the situation. There are other codes you should know about: the P0106 code of faulty MAP sensor, and many others.

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