P0440 minor

Evaporative Emission Control System Malfunction

What does P0440 mean?

The P0440 code means the vehicle's onboard diagnostic system has detected: Evaporative Emission Control System Malfunction. This is a minor severity code.

Common Symptoms

  • Check Engine Light on
  • Fuel odor near the vehicle
  • No drivability issues

Probable Causes (Ranked by Likelihood)

  • Loose or faulty gas cap Very High
  • Leaking EVAP hoses or connections High
  • Failed purge solenoid valve Moderate
  • Faulty vent control valve Moderate
  • Cracked charcoal canister Low

Step-by-Step Diagnostic Procedure

  1. Inspect and tighten or replace the gas cap as the first step.

  2. Visually inspect all EVAP system hoses for cracks or disconnection.

  3. Test purge solenoid with a scan tool by commanding it open and closed.

  4. Perform a smoke test to locate leaks in the sealed EVAP system.

Frequently Asked Questions

Is P0440 serious?

No. P0440 is a generic EVAP system malfunction with no drivability impact. The most common cause is a loose gas cap. It will cause an emissions test failure if not addressed.

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