P0455 Jeep Wrangler DTC Code: EVAP System Large Leak Detected

The DTC (diagnostic trouble code) indicates problems in your vehicle. P0455 Wrangler is one of the diagnostic trouble codes that simply means “Evaporative Emissions Control large leak” 

In this article, we are concerned about what does the P0455 mean? How to get rid of it? And many other aspects. Keep reading to find out more!

What Does P0455 Jeep Wrangler Code Mean?

The OBD-II automotive standard’s trouble code P0455 Wrangler denotes that the PCM has identified a significant leak in the Evaporative Emissions Control (EVAP) system. Note carefully the P0455 error code will be triggered when the leak is “large.”

If we analyze the code P0455, each element will give you the following indication:

P – Powertrain Control Module

0 – A Generic number specified by SAE standards

4- Additional Systems for Emission Control (EVAP)

55- The specific Issue (Large leak)

Technically, the EVAP system comprises charcoal pellets that absorb fuel vapors and release them to the engine’s intake manifold later. Thus, it prevents fuel vapors from being released into the environment.

However, the PCM periodically checks the operation of the evaporative emission control system by closing the vent control valve. This test can be established anytime, regardless of whether your Wrangler is parked or running. 

As the PCM enters test mode, it closes the vent control valve to keep the EVAP system completely sealed off. 

If the system loses vacuum too fast, the PCM deems it a large evaporative emission control system leak. As a result, you’ll notice the check engine light (CEL) is illuminated, which in turn shows the error code P0455.

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

P0455 Jeep Code: What Causes Of EVAP System Large Leak?

Logically, anything that could cause a large leak in the evaporative emission control system (EVAP) will trigger the P0455 trouble code. Since this can happen in many ways, the causes of the P0455 Wrangler code are diversified. However, the most common culprits are:

• Malfunctioning gas cap
• Defective EVAP hoses and filler neck
• Bad charcoal canister
• Deteriorated fuel tank Seal
• Worn vent valve
• Malfunctioning fuel tank pressure sensor or defective connections

How To Troubleshoot & Fix P0455 Jeep Wrangler Code?

By pinpointing the root cause of the P0455 Wrangler code, you can start resolving it. A thorough troubleshooting procedure can help you identify and complete the appropriate maintenance steps. Try to stay organized while you’re troubleshooting.

We typically encourage following manufacturer recommendations, as doing so is the most likely method to success. Keeping all these in mind, we have structured a troubleshooting and fixing procedure below. Let’s proceed with the main process. 

1. Make Sure There Are No Additional Codes

To begin with, plug in your scanner and check if any additional code is stored. When the check engine light (CEL) is turned on in your Wrangler, it can signify lots of issues in the first place. In that case, OBD II scanners will show you DTC codes corresponding to specific issues. 

The scanner may show additional codes like P0456, and P0457, along with the P0455 error code. So, you have to ensure that the CEL is illuminated only for EVAP large leak issue (P0455). This will help you stick to a definite troubleshooting procedure. (www.curlygirldesign.com)  

2. Thoroughly Examine the Gas Cap 

Once you remove all the additional codes, find the root cause for P0455. A common culprit of the P0455 Wrangler code is your fuel tank’s loose or cracked gas cap. Inspecting your tank’s gas cap is a good starting point in troubleshooting the P0455 code. 

First, assess whether the gas cap is sufficiently tightened. If it isn’t, go ahead and tighten the gas cap. However, if the error code is due to a faulty or cracked gas cap, you may need to replace the gas cap. 

Don’t forget to verify the model and pressure specifications listed on the part. This is because the gas cap of modern vehicles is almost interchangeable with radiator caps in terms of specification. If you use the wrong cap, it can trigger the same issue.

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

3. Inspect the EVAP Hose and Filler Neck

Next, If you still notice the trouble code P0455, it’s time to put some attention to the EAP hose and the filler neck. The EVAP hose is hooked up between the fuel tank and the intake system. However, this hose can deteriorate over time and begin to leak. 

This is one of the main reasons leading to the P0455 code. On the other hand, the fuel filler neck can also be the leading cause of evaporative emissions leaks. 

As an exterior component, the fuel filler neck is exposed to the accumulation of dirt, grime, and other harsh conditions that eventually lead to corrosion and leak. 

So, conduct a thorough inspection of all hoses for deterioration. Similarly, keep your eye on the filler neck so visible flaws can be detected and repaired. The expense of the repair for visible flaws could set you back anywhere from $200 all the way up to $800.

4. Examine the Charcoal Canister

If EVAP Hose and Filler Neck are fine and the scanner still shows the error code P0455? you must suspect the charcoal canister. The charcoal canister is one of the most crucial components of the EVAP system. 

This component plays an important role in absorbing toxic carbon emissions. Like any other part, it can be clogged, damaged, or corroded over time and cause an emission leak in the EVAP system. 

So, eventually, the CEL will be turned on. If you experience difficulty filling the gas tank, find a smell of fuel around the vehicle, or make a hissing noise, the charcoal canister can be suspected. 

Here, you should take your Wrangler to a repair shop for a complete inspection. If your mechanic confirms the charcoal canister is malfunctioning or damaged, it has to be replaced. 

5. Go for A Smoke Test

If the error code reappears but you still don’t know the root cause, a smoke test may be the most sensible means for you. This will reveal leaks in the EVAP system and the fuel tank itself.  

However, you should select a top-of-the-line smoke machine for the test. After that, plump the machine directly into your EVAP system. This will help you detect even tinny leaks. 

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

6. Inspect the Vent Valve

If there’s no indication of a leak or apparent damage, inspect your Wrangler’s vent valve for possible blockages or obstruction. Your Wrangler’s onboard computer system controls the vent valve to regulate and balance the flow of emissions. 

From time to time, the vent valve may not work correctly if it’s clogged or leaked due to the accumulation of road salt or dirt. There might be another hose to eliminate some of this dust, but it can not completely clean it.  

So, test the vent valve by releasing hoses from both sides and trying to blow the air. If you can blow air through the valves, then it means that the valves have been sealed properly. Otherwise, the vent valve might have leaked or become sticky. 

7. Check the Fuel Tank Pressure Sensor

The EVAP is designed to entrap unburned vapors and reintroduce them into the fuel system. However, the fuel tank pressure sensor facilitates the detection of leaks in the fuel system caused by defective seals on the fuel cap or evaporative leaks.

Exposure to extreme fluctuations in temperature, vibration, and so on (including corrosive fuel vapors) can cause a malfunction in the fuel pressure sensor. If the sensor is bad or its connections are damaged, it may provide the wrong reading, eventually turning the CEL light. 

So, if you find the gas caps and other components are trouble-free, it’s good to test the fuel tank pressure sensor once. Start with checking whether the connectors or wiring are in good condition. If not, you can repair them yourself. 

Then proceed to the sensor itself. However, a DIY testing process can be difficult. Hence, we recommend going to your dealership or an expert mechanic.

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

FAQs

Perhaps your question is simply the last installment of a long-running inquiry. We’ve made this article to explain P0455 fully. So, we designed this short FAQ section with some common questions. 

End Remarks

Yes, we agree the P0455 Wrangler error code can effectively summon you to nearby repair professionals. However, your issue can sometimes be certainly easy to fix. 

In most cases, you can get rid of the P0455 code just by tightening the gas cap. While it’s critical to find out the problem and fix whatever it stems from, this error code is just a minor blip in the grand scheme.  

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