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P0442

Evaporative emission system leak detected (small leak)

The ECU has detected a small leak in the sealed evaporative-emissions system.

What this code means

The ECU has detected a small leak in the sealed evaporative-emissions system.

Possible causes

  • Loose or damaged fuel cap
  • Cracked EVAP hose
  • Leaking purge or vent valve
  • Damaged charcoal canister
  • Small leak in EVAP pipework

Common symptoms

  • Check engine light
  • Usually no obvious driveability symptoms
  • Possible fuel vapour smell in some cases

Checks to make

  1. Check that the fuel cap is fitted correctly and its seal is undamaged
  2. Inspect accessible EVAP hoses
  3. Check purge and vent valves according to manufacturer procedures
  4. Smoke-test the EVAP system if appropriate

Safety

  • Fuel vapour is flammable. Avoid sparks, flames and smoking when inspecting the EVAP or fuel system.

Model notes

A smoke test is often useful for locating small EVAP leaks.