How do I fix P0456?

Alton Alexander
By Alton AlexanderUpdated on June 4th, 2022

The p0456 code is a generic OBD-II code that indicates a small leak in the evaporative emission control system (EVAP). The EVAP system captures and recirculates fuel vapors from the fuel tank and engine. This code may be caused by a loose or damaged gas cap, a faulty canister purge solenoid, a faulty canister vent solenoid, or a faulty canister.

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1. Check the gas cap to make sure it is on correctly and tight

  1. Open the hood of the car and locate the gas cap.
  2. Remove the gas cap.
  3. Check the gas seal on the cap. If it is damaged, replace the gas cap.
  4. Reconnect the gas cap to the gas tank.
  5. Close the hood of the car.
  6. Start the car and check for leaks.

2. Inspect the EVAP system for leaks

  1. Verify the proper system operation by checking the air/fuel ratio, engine temperature and fuel pressure.
  2. Check for any fluid leaks by using a scan tool and checking for leaks at the air intake, air cleaner, fuel rail, and injectors.
  3. If possible, remove the fuel rail and injectors for inspection.
  4. Check for any fluid leaks at the coolant reservoir, radiator, and engine.
  5. If necessary, replace any faulty parts.

3. Check for any loose or damaged hoses or components in the EVAP system

  1. Remove the front bumper and unscrew the Phillips head screws that hold the front fascia on.
  2. Remove the front grille.
  3. Remove the four screws that hold the evaporator duct in place.
  4. Lift the evaporator duct out of the way.
  5. Check for any loose or damaged hoses or components. If there are any problems, replace the damaged hoses or components.

4. Have the EVAP system tested for leaks

  1. Remove the air ducts.
  2. Inspect the EVAP system for any leaks.
  3. Replace any leaking parts.
  4. Reinstall the fuel tank and air ducts.

5. Replace any damaged or leaking parts in the EVAP system

  1. Remove the EVAP system cover.
  2. Remove the EVAP system pan.
  3. Remove the EVAP system hose.
  4. Remove the EVAP system valve.
  5. Replace any damaged or leaking parts.
  6. Reinstall the EVAP system cover, pan, hose, and valve.