Technical Definition:

Evaporative Emission System

Trouble Code: P0440
Address: 0x0440
System: Powertrain
Technical Description:

This indicates that a part of the EVAP control system is no longer fuctioning correctly. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines, carbon canister, purge valve, and other hoses

Possible Causes:
  • The gas cap is not installed or working properly
  • The purge solenoid has failed
  • The canister is plugged and not working properly

Possible Symptoms:

Evaporative Emission Control System Malfunction

Possible Solutions:
  • Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back.
  • Inspect the EVAP system for cuts/holes in tubes/hoses
  • Inspect for damaged or disconnected hoses around the Evap purge solenoid
  • Check and/or replace the sensor
  • Check and/or replace the purge valve
  • Have a professional use a smoke machine to detect leaks

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Missing or loose fuel cap
– Incorrect fuel filler cap used
– Fuel filler cap remains open or fails to close
– Foreign matter caught in fuel filler cap
– EVAP canister or fuel tank leaks
– EVAP system hose leaking
– Fuel tank leaking

Specific Makes:

– Possible a noticeable fuel odor caused by the release of fuel vapors

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