How to Troubleshoot & Fix P0456 Jeep Grand Cherokee DTC Code?

For most four-wheeler owners, the P0456 might be a minor code they don’t even pay heed to. But we’re glad you’re here to figure out what the code means and how to troubleshoot and fix the P0456 code for your precious Jeep Grand Cherokee. 

If you don’t do anything about the code soon, you risk endangering the performance and safety of your engine and vehicle. And with time, the low costs for repairing minor issues may increase. Thus, without further delay, let’s cut to the chase!

What Does P0456 Jeep Grand Cherokee Code Mean?

The OBD II code P0456 is a universal trouble code. So, it means the same thing, whether it’s a Jeep Wrangler, a Jeep Cherokee, or whatever year it is manufactured. 

Hence, when your control module (ECM) shows the trouble code P0456, it indicates ‘evaporative emission system small leak detected.’

The EVAP system traps all the fuel vapor from the fuel tank and processes them for ignition to the engine’s intake during the combustion process. 

When a small leak in your Jeep Grand Cherokee’s Evaporative Emission Control system, the P0567 code appears. To help you comprehend the code, here’s a breakdown of it-

  • P = OBD-II Powertrain trouble code for the engine
  • 0 = A generic number derived from the SAE standard
  • 4 = Auxiliary emission controls malfunction detected 
  • 56 = Specific fault index (In this case, it denotes evaporative emission control system malfunction)

Causes Of P0456 Jeep Grand Cherokee Code:

Several causes are responsible for the display of code P0456. Sometimes the code appears due to a technical glitch, while in most cases, the code indicates probable leakage in the EVAP system, which needs to be addressed as soon as possible.

Usually, a broken gas cap or a loose fitting is the main culprit. There are plenty of other reasons as well that, include the following:

  • Misplaced gas cap
  • Barrier or accumulation of debris in the fuel filler cap
  • Worn out O-ring of gas cap or fuel filler tube
  • Small leakage in the EVAP canister
  • Disconnected hose of EVAP
  • Malfunctioning vapor canister purge valve
  • Worn-out charcoal canister
  • Defective FTP sensor 
  • Leaks in the control valve or vacuum feed line
  • Drained or dried fuel filler neck gasket

Read Also: How to Troubleshoot & Fix P0128 Jeep Wrangler DTC Code?

How To Troubleshoot & Fix P0456 Jeep Grand Cherokee Code?

P0456 is a low-intensity engine trouble code; the issue may not be severe and won’t likely cause your Jeep Grand Cherokee to break down in the middle of nowhere. But you must take the necessary steps as soon as it is detected. 

As you know, there are multiple reasons for the code. One might trigger another, which would ultimately cause serious harm to your car. We’re here to walk you through the troubleshooting procedure for each potential cause so that you can make a speedy diagnosis. Let’s go ahead 

#1-Look for other OBD-II codes, if any

To begin the troubleshooting, you need an OBD-II scanner,  which you can find in your local stores or online. You need to get one to scan your Jeep Grand Cherokee to find out if other trouble codes persist along P0456. There are possibilities of getting codes P0440, P0441, or P0446 along with P0456.

If that’s the case, there’s probably a leaking charcoal canister, a more extensive or complicated leak in the EVAP system, or solenoid failure. In this case, you must repair the other codes first and get rid of them. 

Here’s a tip, remember to keep a record of your data by freeze-frame data—these act like breadcrumbs for the technician to better comprehend the vehicle’s condition.

#2-Check for a Worn-out or Loosely Fitted Gas Cap

The next step is to look for a worn-out or loose-fitting gas cap. As we already mentioned, a loose gas cap or a worn-out cap might be the cause of the code. So, before troubleshooting other parts, you need to check the state of the gas cap. 

If you’re lucky enough, you might get rid of the code by simply tightening the gas cap. However, if your EVAP system gas cap is wholly damaged or worn out, you should take steps immediately. 

Here’s a catch, there is not always noticeable damage on the gas cap. So, if neither your gas cap is loosely fitted nor damaged, then you should try replacing the gas cap and see if the code is omitted. 

Fortunately, the price range of gas caps for your Jeep is low to moderate. The price for new gas caps generally varies from $23 to $80, and that of gas cap O-rings ranges from $10-$50.

Read Also: How To Troubleshoot & Fix p1494 Jeep DTC Code?

#3-Inspect for EVAP Leaks or Hose Disconnection

If none of the above steps work, you should look for visible leaks in any part of the EVAP system. If none are visible, your following action should be to check for disconnected EVAP system hoses. 

You should also look for any damage or cracks in the hose connected to the EVAP or engine air box. 


The easy but pricey solution to this issue is to replace the hose. Hose prices may typically range from $190-$600. But this is a wise investment because a hose can last for years!

#4-Check for Charcoal Canister and Fuel Tank Damage

If replacing hoses doesn’t work for you either, or you have a set of completely fine hoses, you should inspect the fuel tank and charcoal canister for any damage. 

The charcoal canister is a significant part of the EVAP system, which captures fuel vapors before they are exposed to the outside. 

As for the charcoal, it traps the vapor and keeps it there for some time before it can be recycled back to the engine. The charcoal can get damaged if you frequently fill the fuel tank to the top. 

This creates excessive pressure in the tank, which compels the gasoline into the canister. Besides, due to prolonged use of the canister, debris, and toxins can clog the canister and prevent it from functioning correctly. 

If your charcoal canister is the problem, you might need to pay a reasonable amount to replace it. A canister for your Jeep Grand Cherokee may range from $200 to $600.

Read Also: How To Troubleshoot & Fix P1521 Jeep DTC Code?

#5-Inspect the Charcoal Canister Vent Control Valve

Next, we have the charcoal canister vent control valve, an essential component of the EVAP system. It prevents the vapors of fuel generated from your fuel tank from getting exposed to the atmosphere, preventing air pollution. 

Typically at rest, the valve isn’t powered, which allows air to pass through it. As a result, with prolonged action, it can get greasy or develop accumulations which will result in leaks or solenoid failure, restricting it from working correctly.

As for troubleshooting the vent control, you need to remove the hose from both sides of the vent control valve connected to the canister. Remember to keep the engine off, then simply unplug and remove it from your Jeep.

As the valve isn’t powered on, blow through its openings. Next, supply it with power on one side, and attach the ground to the other side of the electrical connector. 

Try blowing through the openings again; if you cannot do so, it means they are correctly sealed, and the problem is somewhere else. 

However, if it’s the other case, you might need to replace the clogged or damaged valve, costing you about $150-$200. 

#6-Check the Volume Control Purge Valve

As you have ensured everything is fine with the canister vent control valve, it’s time to move on to inspecting the volume control purge valve. To properly diagnose if it’s working correctly, first turn off the key and engine of your vehicle. 

Next, detach the hoses from both sides of the volume control valve. With zero power supply, blow through the openings. Like the vent valve, if you cannot blow, the purge valve is adequately sealed and not responsible for showing the P0456 code. 

However, if you can blow through it, your purge valve might have become greasy, and possibly a leak is there too. To replace a volume control purge valve, you might need to spend about $150-$200. 

#7-Inspect with a Smoke Tester

The EVAP system leak generating the P0456 code is too small to find out with bare eyes. So, if none of the above troubleshooting methods didn’t work for you, get a smoke tester from your local store or online and conduct a smoke test.

Now, fixing the trouble code by yourself will surely cost you less, but you might not always be able to do so. Sometimes, you should seek assistance when a code is generated. 

Similarly, if all the above diagnostic and fixing steps fail for this particular code, take your vehicle to an expert immediately. 

As for an overview of the EVAP system leak problem, there are about 3,400 complaints about the Jeep Grand Cherokee, all issues combined. The complaints were the highest for the particular 2011 model, almost 700. 

However, when specifically checked for EVAP or fuel tank control valve issues, there were only a few complaints about the matter. Seems like a little maintenance or parts fixing can solve the problem with ease.

Read Also: P0455 Jeep Wrangler Code: EVAP System Large Leak Detected


We tried giving you a well-researched discussion and solutions on the P0456 code for your beastly Jeep Grand Cherokee. However, you might still be looking for other basic questions; the ones answered below will help.

Can you drive a Jeep Grand Cherokee with P0456 Code?

The severity of the P0456 code is low, and you can still drive your beast with the code on. However, there might be some complications like higher HC emissions from the leaked spot, flickering check engine light, low acceleration, etc. 

How Much Does It Cost to Fix Jeep Grand Cherokee p0456 Code?

There are plenty of reasons that can work behind the P0456 code generation, hence, different pricing ranges for various causes. On average, it would cost about $50-$500 for parts replacement and about $100 for labor.

What are the symptoms of a faulty EVAP system?

A failing or faulty EVAP system will show typical symptoms of raw or pungent fuel smell generated from the car’s back or bottom, a malfunctioning or leaked fuel tank, or simply the illumination of the Check engine light.


Although the code P0456 isn’t as severe as some other codes might be, there’s no need to procrastinate on troubleshooting and fixing it for your Jeep Grand Cherokee. 

Here’s a tip: Inspect the EVAP purge valve when you notice some symptoms by carrying out an emissions test. Fix the code and take your priceless four-wheeler for a ride!

Read Also: How To Troubleshoot & Fix P0138 Jeep Code? A Detailed Guide

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