What Does P0457 Mean?
The EVAP system has detected a leak, and many manufacturers specifically associate this code with a fuel filler cap issue. This code is often set after the gas cap was left off, not tightened properly, or is defective. Some manufacturers differentiate this from P0455/P0456 to specifically flag the gas cap area. The driver will see a check engine light.
Common Causes
45%
Loose, missing, or improperly seated gas cap
25%
Damaged or worn gas cap seal (cracked O-ring, warped cap)
15%
Damaged fuel filler neck or filler neck seal preventing proper gas cap seating
10%
Cross-threaded or stripped gas cap threads
5%
Using an incorrect aftermarket gas cap that doesn't seal properly
Diagnostic Steps
1
Remove the gas cap and inspect the O-ring seal for cracks, deformation, or debris. Clean the filler neck sealing surface and reinstall the cap until it clicks firmly.
2
If the cap appears worn or damaged, replace it with an OEM gas cap (not aftermarket, as many aftermarket caps do not seal properly). Clear the code and drive one full EVAP monitor cycle.
3
Inspect the fuel filler neck for rust, dents, cracks, or stripped threads that could prevent the gas cap from sealing. Run a finger around the sealing surface to feel for irregularities.
4
If the cap and filler neck are good, perform a quick smoke test focused on the gas cap area and filler neck to confirm the seal integrity.
5
If replacing the gas cap does not resolve the code, expand the EVAP smoke test to the full system as the leak may be elsewhere despite the manufacturer-specific code assignment.
Estimated Repair Cost
$10 - $200
Parts + labor, varies by vehicle and location
The EVAP system has detected a leak, and many manufacturers specifically associate this code with a fuel filler cap issue. This code is often set after the gas cap was left off, not tightened properly, or is defective. Some manufacturers differentiate this from P0455/P0456 to specifically flag the g...
The most common cause of P0457 (Evaporative Emission Control System Leak Detected) is: Loose, missing, or improperly seated gas cap
Typical repair costs for P0457 range from $10 to $200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. This is essentially a gas cap issue in most cases. Tighten or replace the gas cap to resolve. No safety risk or drivability concern.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0457 to identify the root cause.
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Quick Info
Category
Powertrain
System
EVAP / Emissions System
Difficulty
Type
Generic (SAE)
Recommended Tools
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