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ENRUDEPLES

P0440 — Evaporative Emission Control System Malfunction

minor

What it means

A general fault in the EVAP system, which collects fuel vapour from the tank in a charcoal canister and feeds it into the intake to be burned. The ECM runs a self-test by sealing the system and applying vacuum or pressure; when the tank pressure sensor shows that the system neither holds nor purges as expected, the generic P0440 is stored. Symptoms are usually limited to the check engine light and sometimes a fuel smell around the rear of the car.

Likely causes (most common first)

  1. Loose, wrong or damaged fuel filler cap, worn cap seal
  2. Cracked or disconnected EVAP hoses between tank, canister and purge valve
  3. Leaking or stuck purge valve on the intake side
  4. Faulty vent valve or blocked canister filter
  5. Cracked charcoal canister or damaged filler neck
  6. Faulty fuel tank pressure sensor or its wiring

Can you drive with it?

Safe to drive: the fault affects fuel vapour emissions, not engine operation.

This is the generic meaning. What about your car?

The same code has different typical culprits on different engines. Tell the AI your make, model and year — it will rank the causes for your exact car and give you a check order.

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