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2017 Ford Explorer Limited - P0456 Evap Leak (Small) & Gas Cap Light

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Mike T. · rep 0 · May 25, 1:31 AM · 1 replies · solved · Question

Vehicle: 2017 Ford Explorer Limited

I've got a P0456 code popping up on my 2017 Ford Explorer Limited with the 3.5L V6. It's indicating a 'small evaporative emission system leak detected'. Along with the check engine light, I also get a 'Check Fuel Fill Inlet' message on the dash sometimes, which I guess is related to the capless fuel system.

I've tried cleaning the fuel fill inlet area, but the code keeps coming back after a few drive cycles. The car runs fine otherwise, no performance issues. Could it just be a faulty sensor, or is there a common weak point on these Explorers for small EVAP leaks? I'm trying to avoid a costly smoke test right away.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 1:31 AM

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ClearTheCode admin answer:

The P0456 code, indicating a 'small evaporative emission system leak detected,' is a very common issue, especially when combined with a 'Check Fuel Fill Inlet' message on your 2017 Ford Explorer. The EVAP system prevents fuel vapors from escaping into the atmosphere.

Here are the most common causes and troubleshooting steps:

  1. Fuel Fill Inlet (Capless System):

    • Cause: Ford's capless fuel system relies on a tight seal. Dirt, debris, or a worn seal within the fuel fill inlet can prevent it from sealing properly, leading to a small EVAP leak. This is often the first place to check with a P0456 and the 'Check Fuel Fill Inlet' message.
    • Action: Thoroughly inspect the fuel fill inlet for any foreign objects, dirt, or damage to the sealing flaps. Clean it carefully with a non-abrasive cloth and some penetrating lubricant (like WD-40) to help ensure the flaps move freely and seal completely. Cycle the fuel nozzle in and out a few times to help reseat the flaps.

  2. EVAP Purge Valve/Solenoid:

    • Cause: A faulty purge valve can stick open, creating a constant vacuum leak or allowing fuel vapors to escape. This is a very common failure point in EVAP systems.
    • Action: The purge valve is usually located under the hood near the engine. You can test it by applying vacuum and seeing if it holds, or by checking for continuity if it's an electrical solenoid. A common test is to listen for a clicking sound when the engine is running or try to blow through it when it's de-energized (should be closed).

  3. EVAP Canister Vent Valve/Solenoid:

    • Cause: Located near the fuel tank, the vent valve controls airflow into and out of the charcoal canister. If it's stuck open or fails, it can cause a persistent leak.
    • Action: Similar to the purge valve, it can be tested for proper operation. It's more difficult to access, often requiring the vehicle to be lifted.

  4. Damaged EVAP Hoses or Canister:

    • Cause: Over time, rubber hoses can crack, or the charcoal canister itself can develop a crack, leading to a small leak.
    • Action: Visually inspect all accessible EVAP hoses for cracks or loose connections. This often requires a smoke test to precisely locate the leak.

When to See a Shop:

  • If cleaning the fuel fill inlet and replacing the purge valve doesn't resolve the issue.
  • If you're unable to locate the leak after basic checks.
  • When a smoke test is required. A professional shop has the specialized equipment to pressurize the EVAP system with smoke, making even the smallest leaks visible. This is often the most efficient way to diagnose P0456 if the common culprits are ruled out.
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