OBD-II code · Powertrain (generic)
P0457 Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
The EVAP system detected a large leak that strongly correlates with a missing or improperly closed fuel filler cap. After re-tightening the cap, the code clears once the readiness monitor completes.
Is it safe to drive with P0457?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyFuel cap loose, missing, or worn seal
- Less likelyFiller neck damaged
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0–0.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Fuel Filler Cap, Evap Lines
Related codes
- P0454EVAP System Pressure Sensor/Switch A Circuit Intermittent
- P0455Evaporative Emission System Leak Detected (Large Leak)
- P0456Evaporative Emission System Leak Detected (Very Small Leak)
- P0458EVAP System Purge Control Valve A Circuit Low
- P0459EVAP System Purge Control Valve A Circuit High
- P045AEGR B Control Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.