How To Troubleshoot & Fix P0456 Jeep Wrangler DTC Code?

On your off-roading pro-Jeep Wrangler, say out of nowhere, you notice the check engine light is on, and the ECU is throwing a tantrum showing P0456 DTC! 

Now the question is, what does the code mean exactly, or what is the problem with your jeep that the code indicates? Here we are to assist you! To get to every pinpoint of the matter, Keep reading. 

What Does P0456 Jeep Wrangler Code Mean?

P0456 is a universal OBD II trouble code for the vehicles. In your Jeep Wrangler, it indicates an Evaporative Emission Control System (EVAP) Leak Detected [Small]. 

It means that the fuel tank system with the EVAP system between the fuel tank and the engine component of your Jeep Wrangler has a leak, which is a tiny one. 

The evaporative emission control system helps prevent the fuel system’s vapor leaks into the atmosphere. 

The EVAP system routes the fuel fumes from the fuel tank to the charcoal canister storage container through hoses and tubes & reroutes them back to the engine by switching the valve and solenoids. 

Here they are burned in the Jeep Wrangler combustion process. If the sensor of your jeep senses a lack in the purge flow of the EVAP system or fuel vapor leak, P0456 diagnostic trouble code is generated and stored in the PCM or Powertrain Control Module. [source

P0456 is the trouble code for the small leaks only, whereas it will throw the P0455 code for large leaks. If you break down the code, it stands for: 

  • P= Powertrain System of the Jeep [Transmission & Engine] 
  • 0= A generic number derived from the SAE standards
  • 4= Emission controls malfunction 
  • 56= Diagnostic Trouble Code [DTC] Number (As for our case, it is Evaporative Emission System (EVAP) small leak) 

P0456 Code: What Causes an EVAP System Leak on a Jeep Wrangler?

The main cause of the P0456 code in your Jeep Wrangler is the leaks in the evaporative emission system. Several factors can cause the EVAP system to leak. Among many reasons for this issue, the most common is the gas cap of your Jeep Wrangler. 

When the gas cap, usually with the O-ring, goes bad or becomes loose, it causes an EVAP leakage. The ECU of your Jeep Wrangler senses the problem with the system & shows the P0456 trouble code. 

Apart from this, the problem can be due to the following reasons-

  • Disconnected or leaking EVAP hose 
  • Defective purge volume control valve 
  • Leaks in the charcoal canister 
  • Defective canister vent control valve 
  • Bad fuel filler neck or sending unit
  • Fuel tank leak

Read Also: How to Troubleshoot & Fix U1411 Jeep Liberty Code?

How To Troubleshoot & Fix P0456 Jeep Wrangler Code?

Before doing anything else, we recommend you have a complete diagnostic test on your Jeep Wrangler with a diagnostic scanner. It will help you to identify the exact issue & to locate the source of it. 

Moreover, fixing the P0456 trouble code on the Jeep Wrangler is challenging for beginners. For beginners, it will be a hard and time-consuming process. 

However, if you want to diagnose the P0456 code of your Jeep Wrangler, you should follow up on the methods described below. If one method cannot clear the P0456 issue in your jeep, explore the other one. 

#1- Tighten Or Replace The Gas Cap

The first thing to do is to replace the gas cap. In the Jeep Wrangler, most complaints for the P0456 code are because of loose or broken gas caps. Over time, the gas cap seal cracks and cannot be perfectly seated in the filler neck. 

As a result, fuel vapors leak into the atmosphere, which triggers the trouble code in your Jeep Wrangler. 

  • So, first of all, check the gas cap of your Jeep Wrangler to see whether it is loose or deteriorated. 
  • If the gas cap is loose, tighten it to clear the code. 
  • Look for physical damage in case the gas cap is not loose. Replace the deteriorated gas cap with a new one that meets your jeep specs. 

The gas cap of the Jeep Wrangler is relatively cheap, as much as $11.49. To do the job from the experts, it will cost $106, $11 for the parts, and $95 for the labor. [source

[Note: It should also be noted that the damage to the gas cap is not always noticeable. So, if the gas cap of your Jeep Wrangler is not loosened or damaged, try to replace it anyway.] 

#2- Check For EVAP Hoses 

Next, a disconnected or cracked evaporative emission system hose is natural to have a fuel vapor leak in your jeep. 

If tightening or replacing the gas cap cannot resolve the issue, then move to check for the EVAP hoses. 

Check for the connections of the EVAP hoses near the engine air box. If you find the cracked hoses, replace them to clear the P0456 code.

Read Also: How To Troubleshoot & Fix p161B Jeep Patriot DTC Code?

#3- Examine The Charcoal Canister Vent Control Valve

If there is no issue with the hoses, examine the Charcoal Canister Vent Control Valve. 

The charcoal canister vent control valve allows the air to pass through the EVAP system. Over time it gets sticky, causing the leak in the system. 

So, to fix the P0456 Jeep Wrangler code check for the charcoal canister vent control valve to see whether it has cracked. 

  • To check the vent control valve, turn off your engine and disconnect the hoses of the vent valves from the charcoal canister. 
  • Blow air through the valve with no power supply. If the air passes through, the valve is not faulty, or vice versa. 
  • You can also have a test by supplying a fused power source. For an operating vent control valve, the air will not pass through this time. 

#4- Check The Purge Volume Control Valve

Once you have ensured the canister vent valve is blockage free, check for the purge control vent valve. See whether the valve is operating according to the specs of the Jeep Wrangler. 

You can test the valve by blowing air through it by removing the hoses from both sides. You have to perform the test with no power supply to the valve. 

If the purge volume control valve is not faulty or seated properly, you will not be able to blow air through it. 

Otherwise, the valve has blockages or has become sticky, triggering the P0456 code in your Jeep Wrangler.

Read Also: How To Troubleshoot & Fix P0441 Jeep DTC Code?

#5- Inspect the Jeep Wrangler Charcoal Canister & The Fuel Tank

Often the gasket is where the fuel filler neck and the gas tank connect. Sometimes the gasket dries out, especially in dry climates. 

When that happens, the fuel tank can’t hold the pressure causing a fuel vapor leak. So have an inspection about this matter also.

A leak on the charcoal canister or fuel tank can also trigger the P0456 trouble code on the Jeep Wrangler. Therefore, inspect these two, and if you find any faults, repair or replace them as needed. Replacing the charcoal canister is easy. 

If you want to replace the canister yourself, you can take the help of the video below. Otherwise, replacing the charcoal canister may cost you about $151 for your jeep. [source

#6- Run A Smoke Test

Sometimes the leak on the EVAP system is so small that it becomes challenging to find. After having all the fixes and checks that have been listed above, you may have to have a smoker test with the help of a smoker machine. 

You can buy the tester to have the diagnosis yourself. Sometimes the leak is too small that it is difficult to find out. In that case, you might have to hire a professional. [source

Read Also: How to troubleshoot & Fix P06dd Jeep Wrangler DTC Code? [Top 4 Fixes]

Frequently Asked Questions [FAQs] 

For further assistance, we have listed some of the most searched queries by Jeep Wrangler owners for the P0456 code. Hope this will help to gain more knowledge about the matter. 

Can you drive a Jeep Wrangler with the P0456 code?

Yeah, you can drive your Jeep Wrangler with the P0456 code. But it is not wise to do so. Besides, if you continue driving with the code where the vehicle has an EVAP system, it’ll continue to emit harmful gasses into the environment. 

How Much Does It Cost to Fix Jeep Wrangler P0456 Code?

Fixing the Jeep Wrangler P0456 code will cost you about $95 to $110. But the cost of fixing it depends on the damages to your Jeep Wrangler evaporative emission system. 

How serious is the P0456 trouble code in the Jeep Wrangler?

When the ECU of your Jeep Wrangler detects small leaks in the evaporative emission system, it throws up a P0456 code. You have to get the matter resolved within the next month not to face the problems of driveability and excessive fuel consumption. 


Most of the time, the Jeep Wrangler owner will not mind having a P0456 trouble code as it has no immediate impact on the vehicle and is low severity. But the thought is wrong! 

If you leave it unattended, the trouble code can lead to a lack of driveability and expensive repair. So, it is a wise idea to resolve the matter before it’s too late!

Read Also: How to troubleshoot & Fix C121C Jeep DTC Code?

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