P0440low severityPowertrain

Evaporative Emission Control System Malfunction

on 2014 GMC Terrain 2.4L I4 · FWD

What this code means

General EVAP system malfunction. The EVAP system captures fuel vapors and prevents them from escaping to the atmosphere.

Symptoms

  • Check Engine Light
  • Fuel smell
  • Failed emissions test

Common causes

  • Loose or missing gas cap (most common)
  • Cracked EVAP hose
  • Faulty purge valve
  • Faulty vent valve
  • Charcoal canister saturated
  • Leak in fuel tank or filler neck

Diagnostic steps

  1. Check gas cap seal and tighten
  2. Perform EVAP smoke test
  3. Test purge valve
  4. Test vent valve
  5. Check EVAP hoses
  6. Inspect charcoal canister

Repair notes

Start with gas cap - tighten and clear code. If returns, smoke test the EVAP system.

Other Powertrain codes on this vehicle

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