Powertrain fault code
P0455: Evaporative Emission System Leak Detected (Large Leak)
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Not dangerous to drive. Start with the cheapest fix: the fuel cap.
What P0455 means
The system that captures fuel vapour from the tank has a leak or a faulty valve.
Common causes
- Loose or worn fuel cap (very common)
- Cracked EVAP hose
- Faulty purge or vent valve
What to check first
- Make sure the fuel cap clicks shut and its seal isn't cracked.
- Clear the code and see whether it returns after a few drives.
- Have a smoke test done if it comes back.
P0455 on popular makes
P0455 on a Chevrolet
- Start with the fuel cap: missing, loose or a worn seal.
- On GM vehicles the EVAP vent solenoid near the charcoal canister is a commonly reported cause.
P0455 on a Toyota
- Check the fuel cap first, then the EVAP hoses.
- The charcoal canister and its vent valve are commonly reported causes on Toyotas.
P0455 on a Ford
- Check the fuel cap or capless filler neck for dirt or damage first.
- A faulty purge or vent valve and cracked EVAP hoses are common next steps.
Read your car's codes yourself, free
Plug a cheap ELM327 OBD-II adapter into the port under the dashboard and open the scan tool: Chrome or Edge on a computer with a USB adapter, or Chrome on Android with a Bluetooth LE adapter. It reads and clears codes and shows emissions readiness. It does not work on iPhone.
Open the free scan toolRelated codes
General guidance only, not a diagnosis. A qualified mechanic should confirm the cause before you replace parts.