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P0455

Evaporative emission system gross leak detected

The ECU has detected a large leak or inability to seal the EVAP system.

What this code means

The ECU has detected a large leak or inability to seal the EVAP system.

Possible causes

  • Fuel cap missing or not sealing
  • Disconnected EVAP hose
  • Large cracked hose
  • Stuck vent or purge valve
  • Damaged canister

Common symptoms

  • Check engine light
  • Possible fuel-vapour smell
  • Usually no major driveability symptom

Checks to make

  1. Check fuel cap first
  2. Inspect EVAP hoses and connections
  3. Check purge/vent valves
  4. Use smoke testing to locate a large leak

Safety

  • Do not replace parts from the code alone. Confirm the fault with live data, wiring checks and manufacturer procedures. Keep clear of hot or moving engine components.

Model notes

The code definition is generic; exact diagnostic thresholds, component locations and repair procedures vary by vehicle.