What P0455 means
A large leak in the sealed fuel vapour system. The overwhelmingly common cause is the fuel cap.
Common causes
- Loose, cracked or wrong fuel cap
- Disconnected EVAP hose
- Cracked charcoal canister
- Stuck-open vent valve
How it is usually fixed
- 1Tighten the cap and drive several cycles before anything else
- 2Replace the cap if the seal is hardened
- 3Smoke-test the EVAP system to find the leak
Other common codes
- P0011 — Camshaft Position A – Timing Over-Advanced (Bank 1)
- P0030 — HO2S Heater Control Circuit (Bank 1, Sensor 1)
- P0101 — Mass Air Flow Circuit Range/Performance
- P0113 — Intake Air Temperature Sensor Circuit High
- P0118 — Engine Coolant Temperature Sensor Circuit High
- P0131 — O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
Code information is general guidance, not a diagnosis for a specific vehicle. Confirm with live data and manufacturer test procedures before replacing parts.