Chevy Tahoe P0455: Large Leak Diagnosis by EVAP System

The most frequent trouble code with the Chevy Tahoe The Code P0455. This code is used to refer to the number given when you connect your Tahoe to an OBDII scanner. The trouble code P0455 indicates that the vehicle is experiencing a problem. Leakage large In the evaporative emissions control system. It is frequently found in conjunction with other codes such as P0420 or P0441.

P0455: System Gross Leak Evaporative Emission

Your Tahoe's driveability is generally not affected by P0455. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though. This is usually accompanied by P0442. For more information, see Chevy Tahoe OBDII code P0442.

Chevy Tahoe P0455 Definition

The universal OBDII code P0455 can be used to diagnose trouble codes. The code can be used regardless of the make and model of the vehicle. Technically speaking, this code refers to:

System Gross Leak Evaporative Emission System

The EVAP system collects fuel vapor from your fuel tank. It then sends it to the intake to ignite the engine in normal combustion. When there is a large leak in the Chevy Tahoe’s EVAP system, it will throw the P0455 OBDII Code.

Chevy Tahoe P0455 OBDII Code Symptoms

A P0455 Code will usually not cause any symptoms except the ones listed below. The smell of gas The service engine soon light. The slightest drop in fuel economy may also be noticeable.

Particular attention should be paid to the gasoline smell around your fuel filler tube or tank.

The EVAP process deals with fuel vapors directly. If these vapors are leaking from the system, you’ll often smell them faintly while operating the vehicle.

Tahoe P0455 Troublecode Causes

Many things can trigger the P0455 code in Chevy Tahoe. These are some of the more common issues that can trigger the code.

• Hose of the Evap System– The hose that carries the fuel vapor from the fuel tank to the intake manifold can begin to leak. The P0455 error code will be generated. It should be checked for tears or holes. This is the leading cause of code.
• Vapor Canister Purge Valve– One of the most common causes of the P0455 code is the vapor canister purge valve. It’s really easy to replace. There are some clips you will need to look for and then remove.
• A Faulty Canister of Charcoal– The charcoal canister is often the cause of P0455.
• Fuel Tank Sending Unit– It is possible for the gasket that attaches the fuel sending unit to the gas tank to go bad. This could cause a drop in tank pressure which can throw off the code.
• Fuel Cap– A bad fuel cap can cause the code to be thrown for sure. Often, you’ll get a message informing you that the fuel cap is off even when it is on. You may not get the message but a P0455. This will save you time and money.
• Fuel Filler Neck– There is often a gasket where the fuel filler neck connects with the gas tank. The gasket may dry out especially if the vehicle is in dry conditions. When it dries out, the fuel tank can’t hold pressure anymore.

Chevy Tahoe Diagnosis - P0455

The mechanic will have a lot of different tools at his disposal in order to determine the cause of your Chevy Tahoe P0455. The most commonly used methods to diagnose this code are:

• The mechanic will check to make sure there are no other codes. It is easier to diagnose problems if there are more codes. That’s because when they appear together in certain combinations, there will often only be only a few conditions that will throw any combination of codes at one time.
• The mechanic will normally determine what trouble codes are associated with P0455. Take a look at the EVAP system. These include the line and purge valve.
• A mechanic will examine the gas cap and verify that it is able to withstand high pressure. If you are getting a warning that your gas cap is off, even when it’s on, replacing it will more than likely clear this code.
• Monitoring and checking the fuel tank pressure is a must.
• The mechanic will then perform the following tests after completing the above-mentioned checks:
• A smoke test, and they’ll use a scan tool to confirm that the EVAP solenoids and valves are operating properly.

Here’s a pretty good video on diagnosing these leaks from Scotty Kilmer, if you are interested:

While the trouble code may state that there is a “large leak” in the EVAP system of your Chevy Tahoe, the actual leak will most likely still look rather small. The “large” really is referring to how much pressure is being lost.

The Most Popular P0455 Fixes

These are some of the most popular Tahoe P0455 solutions:

• Replacing the gas cap
• Replacement for EVAP lines
• Replace charcoal canister
• Change the fuel tank

It is best to begin with the gas cap, and then work your way up to the fuel tanks. The gas cap is the most difficult and cost-effective item to replace.

Here’s a great video on How to test your gas tank.

You will need to solve the problem. We trust this helped. You can add any additional information by leaving a comment.

Do you consider P0455 to be a serious concern?

While P0455 is not going to cause the Tahoe’s engine to stop running, it should not be treated lightly. There could be fuel contamination. Check your tank regularly to make sure there is no fuel leaking. It is best to have it checked and/or dealt with immediately.