The P0456 is an OBD-II generic trouble code that stands for Evaporative Emissions System Small Leak Detected. This code is triggered when the vehicle’s computer detects a small leak in the EVAP.
In this article, I will be talking about P0456, its symptoms, causes, and how to fix it.
What Does The P0456 Trouble Code Mean?
The P0456 is an OBD-II trouble code which means the vehicle’s computer has detected a very small leak in the evaporative system during the system check. The leak is measured in barometric pressure and a small leak means a drop of .01.
The EVAP system keeps everything sealed and prevents gasoline vapors containing hydrocarbons from escaping into the atmosphere. The gasoline is liquid but it evaporates so quickly. Therefore, the inability of the evaporative system to keep the gasoline vapors inside the vehicle causes a P0456 trouble code.
Which Models Are Affected By The P0456 Trouble Code
| Make | Affected By P0456 Code |
|---|---|
| Toyota | Yes |
| Nissan | Yes |
| Chevrolet | Yes |
| BMW | Yes |
| Audi | Yes |
| Buick | Yes |
| Mercedes | Yes |
| GMC | Yes |
| Suzuki | Yes |
| Tata | Yes |
| Lexus | Yes |
| Mazda | Yes |
| Mitsubishi | Yes |
| Kia | Yes |
| Jeep | Yes |
| Fiat | Yes |
| Honda | Yes |
| Hyundai | Yes |
| Opel | Yes |
| Ford | Yes |
| Fiat | Yes |
| Peugeot | Yes |
What Are The Possible Causes of The P0456 Trouble Code?
The P0456 is caused by a small leak in the evaporative system. The EVAP system is completely sealed and as little as a .01 drop in the pressure can trigger the P0456 code. When this happens, the vehicle’s computer reports this to the driver by igniting the check engine light.
Possible causes of the P0456 trouble code include:
- Missing, loose, or damaged gas cap
- Leaking EVAP hose
- Leaking fuel tank
- Pinhole leak
- Leaky purge control valve
- Faulty evaporative vacuum pump
What Are The Common Symptoms of The P0456 Trouble Code?
Common symptoms of the P0456 trouble code include:
- Decreased fuel economy
- Check engine light
- Fuel smell inside the cabin
- Could possibly fail an emissions test
Is It Safe To Drive With a P0456 Trouble Code
As far as the well-being of the vehicle goes, you can safely drive with a P0456 code. Other than decreased fuel economy, you won’t feel any changes in the way the vehicle drives. However, driving with a P0456 trouble code or an evaporative emissions small leak means that harmful hydrocarbon gases are escaping into the atmosphere.
How To Diagnose The P0456 Trouble Code
To diagnose the P0456 trouble code:
- To diagnose the P0456, the vehicle has to be scanned with an OBD2 scanner. The scanner can show you exactly when the fault happened.
- Inspect the vapor purge valve system along with the purge valve and the vent valve hose. Look for any loose or damaged connections.
- Check the purge valve vent. Look for any blockage that might have been caused by dirt and debris that prevent the valve from completely sealing the vapors.
- Perform a smoke leakage test on the fuel vapor system. This will help locate where the vapor leak is.
- Test the purge control valve to see if it’s able to hold a vacuum when engaged.
How Much Does It Cost To Repair P0456 Trouble Code
| Make | P0456 Code | Repair Cost |
|---|---|---|
| Toyota | Yes | $100 – $500 |
| Nissan | Yes | $100 – $500 |
| Chevrolet | Yes | $99 – $470 |
| BMW | Yes | $100 – $500 |
| Audi | Yes | $100 – $500 |
| Buick | Yes | $70 – $300 |
| Mercedes | Yes | $100 – $600 |
| GMC | Yes | $100 – $500 |
| Suzuki | Yes | $100 – $500 |
| Tata | Yes | $60 – $480 |
| Lexus | Yes | $100 – $500 |
| Mazda | Yes | $100 – $500 |
| Mitsubishi | Yes | $100 – $500 |
| Kia | Yes | $85 – $485 |
| Jeep | Yes | $100 – $500 |
| Fiat | Yes | $100 – $500 |
| Honda | Yes | $100 – $500 |
| Hyundai | Yes | $100 – $500 |
| Opel | Yes | $72 – $375 |
| Ford | Yes | $100 – $500 |
| Fiat | Yes | $80 – $400 |
| Peugeot | Yes | $100 – $500 |
What Repairs Can Fix The P0456 Trouble Code
Repairs that can fix the P0456 code include:
- Replacing the gas cap
- Cleaning the gas filler neck with WD40 and a clean towel
- Replacing a faulty canister purge valve
- Replacing a leaky EVAP hose
- Repairing or replacing a leaky fuel tank
- Replacing a faulty evaporative vacuum pump
How To Fix The P0456 Trouble Code
Here is how to fix the P0456 code:
- Replace the damaged gas cap
- Replace or clean the clogged purge vent valve
- Replace the leaking purge valve
- Replace the leaky fuel tank
- Clean the gas filler neck
- Replace the faulty EVAP vacuum pump
In Conclusion
The P0456 trouble code stands for Evaporative Emissions System Small Leak Detected. Although the car is driveable with this code, the ride will not be pleasant. The vehicle will start to burn more gas than needed in order to compensate for the lost air.