Diagnostic Trouble Code (DTC): P0457
Definition of the P0457 code
When the PCM (powertrain control module) detects a leak in the evaporative emission control system, the P0457 code is stored and the Check Engine light comes on.
What the P0457 code means
The fuel vapor emission system is designed to prevent fuel vapor 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 differ in the severity of the leak. The P0457 code refers to the most severe leak, while the P0455 code refers to a minor leak.
What causes code P0457 to occur?
Since the P0457 code is only recorded when there is a major leak, many minor problems that can cause a P0455 or P0456 code can be ruled out. In most cases, the P0457 code is recorded because of this:
- Missing, cracked or loose fuel cap.
- Cracked or rotten hose
- Cracked vacuum cleaner container
- Since this system is protected from the elements, code P0457 is not normally caused by aging system parts and instrumentation.
What are the symptoms of the P0457 code?
In general, the performance and driveability of the vehicle will not be affected by P0457, although in some cases a drop in fuel efficiency may be noticed if the fuel leak is large enough. In most cases, however, the only indicator the driver or vehicle owner will receive will be the check engine light coming on.
How can a mechanic diagnose the P0457 code?
Since the P0457 code usually produces no symptoms other than the Check Engine light coming on, it is necessary for the mechanic to 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, the 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 the fuel cap, the mechanic will proceed to check the rest of the fuel vapor emission control system.
Most common errors in the diagnosis of P0457 code
Sometimes this problem occurs simply because the fuel cap is not properly tightened, which may lead the vehicle owner and/or mechanic to 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 serious code related to a leak in the evaporative emission control system. This can increase your vehicle’s emissions and fuel economy. Depending on the problem, it can lead to even more fuel leaks on the road, which can be more costly and can cripple your vehicle until it is repaired.
What repairs can clear a P0457 code?
The most common repair for this code is to make sure the fuel cap is tight or replace it. Other repairs include:
- Replacement of one or more vacuum hoses of the fuel vapor emission control system.
- Ensure that the intake manifold connector is tight and free of cracks, and replace if damaged.
- Replace the charcoal cartridge if it shows signs of cracking.
Additional notes on code P0457
The P0457 code should be fairly simple to address and resolve. However, it is important to perform a thorough visual inspection, as ignoring a fuel cap problem can result in the replacement of perfectly good fuel vapor emission control system components, resulting in a more costly repair than necessary.
