P0456 OBD Error Code: Problem & Solutions

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Is the check engine light illuminated on the dashboard? Do you smell some fuel odour while driving? These might me indication of Emission control system failure causing P0456 error getting stored in the PCM (Powertrain Control Module).

The charcoal canister contains charcoal which absorbs and stores the fuel vapours. When the time comes to “purge” the vapours, fresh air passes over the charcoal and this releases the vapours. When engine operating conditions are correct, the purge solenoid opens the purge valve. This allows fuel vapours to be sucked into the engine and burned.

Enhanced EVAP systems use a canister vent solenoid and valve during system self-testing. The PCM closes the valve, sealing the canister off from outside air. Then, the PCM can monitor the closed system and check it for leaks. Once the engine is shut down, the powertrain control module (PCM) tests the integrity of the EVAP system. It does this by closing off the system and monitoring pressure/vacuum to check for leaks. Code P0456 indicates the PCM has detected a small leak in the EVAP system during testing.

What causes this problem with the Evaporative Emission System Small Leaks?

• Small leak in any of the EVAP hoses or fuel tank hoses
• Small leak in the purge valve or vent valve
• EVAP Canister leaking
• 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
• Evaporative Emission (EVAP) canister or fuel tank leaks
• Evaporative Emission (EVAP) system hose leaking
• Fuel tank leaking

1. Fuel Tank Filler Neck - Vapour leaks from the filler neck can be a reason for OBD code getting stored in the system. Replace it, if required to correct this error.
2. Fuel Tank Vent Valve - Faulty valve can cause pressure differences and thus causing performance issues. Replace old vent valve, if faulty.
3. Vapour Canister Valve - Inspect for canister valve leakages and damaged valves and replace them now!
4. Fuel Tank - Damaged fuel tank will cause contamination and leakages, thus causing performance issues. Replace it now!
5. Fuel Tank Cap - Check for damaged tank cap for leakages and that might be loose and replace them now!
6. Diagnostic Tools - You will require quality diagnostic tools to resolve this OBD issue. Buy factory grade tools from us!

We at Parts Avatar Canada care for our customers, and that’s why we will help you to diagnose P0456 code by listing out some major symptoms. They are mentioned below as follows:

Common Symptoms

This error has no specific symptoms other than Check Engine Light illumination and thus needs proper examination to sort this problem. In rare cases, the driver may smell fuel odour but that too is limited to certain cases due to release of vapours from the EVAP system.

After you know the symptoms of your vehicle’s problem, it becomes easy to detect it and get started with solving it. So, next on our list is few common steps to correct this issue with your vehicle.

• Faulty wiring repair or replacement
• EVAP pressure sensor repair or replacement
• Fuel cap replacement
• Faulty EVAP valves replacement

Don’t get tensed if you are still facing any of these issues as we care for our customers and that’s why we offer a good range of Fuel Tank Filler Neck, Evaporative Vent Valve, EVAP Purge Switch, Carbon Canister, Fuel Tank, Fuel Cap and a lot more. We are sure that now all your issues would be resolved.

It is essential to diagnose this fault code. Here are some steps which a mechanic should follow for diagnosing the problem that triggered a P0456 code to be stored:

• Scan codes and document the code in the PCM, view the freeze frame data to see when fault happened. Inspect the entire vapour purge valve system to include the purge valve and vent valve hose connectors for damaged or loose connections 
• Check the purge valve vent for any blockage from dirt, debris or spider webs that could cause the valve to not be able to complete a total seal of the vapours. Perform a smoke leakage test on the fuel vapour system to try and locate the cause of the vapour leak using the test vapour port, checks the fuel cap for vent leakage
• Check the purge control valve to see if it will hold a vacuum when activated. Also check for faults in the PCM and repair or reprogram as required.

Common Mistakes When Diagnosing the P0456 Code

Not checking and assuming the purge control valve is defective without doing a thorough diagnostics of the complete system to later find the wiring is broken or cut, not verifying the leak and replacing parts that may or may not be the problem, and not checking for any technical service bulletins that may have a fix for the code are some of the common mistakes.