How to Troubleshoot & Fix P0456 Jeep Patriot DTC Code?

The onboard computer of your jeep patriot looks out for errors in the system. When it finds any issue, it stores the DTC code. P0456 is a kind of DTC code that indicates an issue in the evaporative system of the Jeep.

Although the code is not serious enough, you must take the necessary step. No worries, we will discuss every bit of detail about P0456 including what are the reasons, and how to fix them.

What Does P0456 Jeep Patriot Code Mean?

P0456 jeep patriot code means Evaporative Emission Control System Small Leak. The PCM detects a small leak or hole in the evaporative system of the jeep patriot and activates this code to alert you.

The function of the evaporative emission system is to control the emission of vapor and air into the atmosphere. During the combustion process of the jeep, this system absorbs all the fuel vapor inside the fuel tank. 

Then sends this vapor to the intake for combustion. It prevents the unfiltered gasoline from coming into contact with the outside environment.

The PCM performs a test. It closes up the evaporative system within a small vacuum to monitor for any kind of leaks. 

If it detects a leak smaller than 0.020 inches in diameter, then the PCM activates the check engine light and shows the p0456 code.

The breakdown of code P0456 is:

  • P = Powertrain, the system of components that propels the jeep forward
  • 0 = A generic number derived from the SAE standard
  • 4 = Malfunction in the Evaporation system
  • 56 = Evaporative Emission Control System Small Leak

P0456 Code: What Causes Evaporative Emission Control System Small Leak on Jeep Patriot?

The first thing you should do for clearing this code is to know the root cause. Usually, the gas cap tends to be the main culprit for this code’s appearance. 

Other than that, here are the causes of the small leak in the evaporation system of your jeep patriot:

  1. Loose or damaged gas cap
  2. Cracked or leaking evaporation hose
  3. Malfunctioning purge vent valve
  4. Leaking vapor charcoal canister
  5. Incorrect fuel filler cap installation
  6. Damaged fuel tank
  7. Blockage in the fuel filler cap
  8. Faulty FTP sensor

Read Also: How to Troubleshoot and Fix P0507 Jeep Commander DTC Code?

How to Troubleshoot & Fix P0456 Jeep Patriot Code?

Inspecting the affected components and parts is the next step in troubleshooting code p0456. 

Check the fuel cap, fuel tank, evaporation hose, charcoal canister, and purge vent valve -all of these components to diagnose the problem. Then follow the fixes accordingly to clear the code.

1. Check for Leaks in the Fuel Cap

The fuel cap on top of the fuel tank is meant to be sealing the fuel inside. It also prevents dirt, dust, and debris from entering the system. 

This fuel cap is the component that captures the fuel vapor and keeps it inside the fuel tank. This is the main component for the prevention of fuel emissions escaping outside. 

The fuel cap is removed and secured every time the fuel is filled in the tank. As a result, over time it wears out. The cap becomes way too loose to be secured tightly on the tank. 

As a result, a prominent leak is created in the evaporation system due to this loose or damaged fuel cap.

To decide whether or not you need to replace the fuel cap, inspect the cap very closely. Perform a pressure test on the fuel cap to check its functionality. If the fuel cap is too damaged, it won’t pass the emission or pressure test. 

You will receive a notification that indicates the fuel cap is off even after securing the cap properly. It means that the fuel cap has completely failed. So, replace the fuel cap with a new one. 

2. Look for Cracks in the Evaporation Hose

The evaporation hose acts as a connector between the evaporation system. It connects the fuel tank and the intake manifold. 

The fuel vapor or emission goes through this evaporation hose to the intake manifold during combustion. 

However, any kind of damage or overuse can cause cracks to appear in this evaporation hose. Even the smallest cracks or leaks in the hose can let the fuel vapor out into the atmosphere. 

As a result, the evaporation system will fail to do its job due to leakage and show the p0456 code.

Thoroughly inspect the evaporation hose all the way from the intake manifold to the fuel tank. The hole or leak could be anywhere on the hose. Locate the crack and try to repair it as best as you can. 

If the crack is irreparable, replacing the evaporation hose will be the best course of action.

3. Inspect the Purge Vent Valve

Another essential part of the evaporation system is the purge vent valve. It is basically a solenoid that is electrically operated by the ECM. This purge valve controls the fuel vapor amount purged from the charcoal canister. 

The purge flow of the fuel vapor is constantly monitored by the PCM. When the purge valve malfunctions, the purge flow either gets reduced or increased. 

A defective purge valve is found by the PCM once it notices this change. Consequently, the code p0456 is displayed.

The purge valve location and type might vary from the model and year of the jeep patriot. So, first, you have to locate the purge valve on your specific jeep by using the manufacturer’s manual. 

Remove the clips attached to the valve to get it free. Then replace the purge valve with a suitable and similar model. 

4. Examine the Fuel Filler Cap

There is a fuel filler cap located between the fuel filler neck and the fuel tank. This cap seals off the fuel filler neck protectively. As a result, the gas vapor inside the fuel tank does not get out of the atmosphere. 

This fuel filler cap might face blockage inside due to the accumulation of dirt and dust. It clogs up the pathway and slowly starts damaging the component due to wear. 

Another issue with the fuel filler cap might be its improper installation of it. While putting the evaporative system together, this cap might not have been installed in the right place. 

If the cap has not been tightened enough properly in its place, that can also be the reason for code p0456.

First of all, ensure that the fuel filler cap on your jeep is properly placed. Check its location and then move on to check if it is tightened enough. 

If you find any issues with the installation, it is better to take the component apart and place it properly again. Make sure it is fastened securely so that no gas vapor can leak out.

In case you find a blockage in the filler cap, clean it carefully with a thin brush. You can also use compressed air to clean any loose dirt or dust inside the cap thoroughly.

5. Check for a Saturated Charcoal Canister

The charcoal canister is an essential component of the EVAP system which is connected to the purge vent valve. During refueling, the fuel vapor flows through the charcoal canister. 

The carbon inside the canister flushes the vapor out and burns it in the engine.

If the charcoal canister is over-saturated, it fails to absorb any more gas vapor. So, the excess gas vapor starts to leak out little by little. 

Because of this, the evaporation system faces a small leak that leads to code p0456. 

You will need to replace the charcoal canister to fix this issue. It is a pretty rare occurrence so the chances of this happening are very low. All you will need for this replacement is a few hand tools. 

Remove the clamps and sockets to free the charcoal canister and secure a new one in its place. You can seek help from an expert for this advanced replacement.

6. Diagnose the Fuel Tank for Leaks

The fuel tank is basically the holding component of the fuel in your jeep patriot. If the fuel tank leaks, it not only causes the code to appear but also creates risks of explosion. 

If there is a leak in the fuel tank, the gasoline will drip down and accumulate on the ground below the jeep. It is pretty easy to spot and locate. 

You will recognize the fuel leak from the strong smell of petrol and its color. This leak can happen due to any hard damage to the fuel tank or corrosion.

Once locating the leak in the fuel tank, you can repair it pretty easily. Any repair shop will weld the leak shut instantly and repair it. There is no need to replace the fuel tank unless there is a big rupture in it.

Read Also: How to Troubleshoot & Fix P0394 Jeep Wrangler DTC Code? Comprehensive Explanation!


In order to clear the code p0456 on the jeep patriot, you need to know the answers to the following questions as well.

Can you drive a Jeep Patriot with the P0456 code?

Yes, it is safe to drive a jeep patriot with a p0456 code. The leak is very small so the only effect of it will be increased carbon emission from the jeep. The check engine light will also not turn off.

How much does it cost to fix Jeep Patriot P0456 code?

The cost to fix the p0456 code can range anywhere from $60-$600 depending on the specific part you need to replace. Plus the labor cost of this will always be between $75-$150. 

What are the symptoms of the Jeep Patriot P0456 code?

The main symptoms of the jeep patriot p0456 code are a strong fuel smell and an increased amount of emissions from the jeep. Illuminated check engine lights and poor fuel economy are also symptoms of this.


P0456 jeep patriot code is not that common of an error code for most vehicles. But you must take the necessary steps to fix it. 

Sometimes, locating the exact leak might be extremely hard due to the tiny leak in the evaporation system. Feel free to contact a professional for a proper diagnosis.

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