Skip the auto shop - Our mechanics make house calls

P0455 OBD-II Trouble Code: System Gross Leak Evaporative Emission

check engine light logo

P0455 Trouble Code definition

System Gross Leak Evaporative Emission

The Code P00455 code is often associated with P0440 code.

What the P0455 code means

P0440 is the general code for a problem with the Fuel Evaporative Emission System. The P0455 code specifically indicates a large leak in the system, not a fuel leak, but one in the vapor recovery system.

What causes the P0455 code?

The leak can be caused from a variety of components. The most common is related to the fuel filler cap which could be missing, not correctly installed, not sealing properly or may be damaged to the top of the filler neck.

The next most frequent problem is a leak in a hose. Hoses on the breather system tend to crack with age including the large connecting hose on the filler neck to the tank. The Evaporative Emission System has a purge valve to regulate pressure in the system and this will need to be checked by a technician.

Vehicles with a charcoal filter on their evaporative system need to check the filter for cracks, damage, or leaks. The fuel tank itself may be leaking or the gasket where the fuel level sensor, pressure sensor, and fuel pick attach to the tank may be leaking. See the manufacturer's diagram of the system to verify components and their locations. Note that even if the code indicates a large leak, it may actually be fairly small.

What are the symptoms of the P0455 code?

P0455 will generally be preceded by the Check Engine Light coming on the dashboard’s display. There can be a noticeable gasoline fuel smell in the filler area or tank area. It is also possible the smell could also becoming from the evaporative lines to the engine intake system.

How does a mechanic diagnose the P0455 code?

P0455 is diagnosed with an OBD-II scanner. The technician should then reset the OBD-II fault codes and road test the vehicle to see if the code comes back and he can observe this by watching it live on his scanner while driving.

If the code comes back, then the mechanic will need to do a visual inspection to determine any obvious leaks. If no leaks are seen, then the next step is to use a smoke test on the system to look for a leak. If there is no leak noted, then there may be a sensor issue that will need to be tested by the manufacturer's instructions as each system is slightly different.

Common mistakes when diagnosing the P0455 code.

Diagnostic errors are largely due to not following the procedure. The process is a logical and economically sound way to proceed. If you need a fuel cap, they are usually less than $30, but other components such as the Evaporative Emission System purge valve can cost several hundred dollars

How serious is the P0455 code?

P0455 code will not affect the way the car drives, but if the fuel odors are very strong or have obvious fuel leaks, take the car to a qualified technician as soon as possible. The system leak failure can cause excessive fuel consumption in certain circumstances so it is best to take to a technician at your first opportunity. Occasionally, if no problems are found, the technician can reset the fault codes, then retest. Note, that to do proper testing the fuel tank, it should be 1/4 to 3/4 full to ensure proper conditions to test. Often times, if the Check Engine Light came on immediately at start up, the OBD-II system can be reset and the vehicle will operate normally.

Often times, if the Check Engine Light came on immediately at start up, the OBD-II system can be reset and the vehicle will operate normally.

What repairs can fix the P0455 code?

Potential repairs to P0455 are:

Additional comments for consideration regarding the P0455 code.

Many vehicles with mileage over 100,000 have momentary sensor problems that usually occur during start up or prolonged stress situations on the drive train. If the Check Engine Light comes on and the vehicle seems to be operating normally, the OBD-II system can be reset using the scanner and the problem may not reoccur. This is why it is important to verify the fault and reset it before doing any repairs.

Need help with a P0455 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How Long Does a Throttle Return Spring Last?
Not all vehicles on the road feature an electronic throttle control (ETC), which is also called drive-by-wire. For vehicles that don't offer this system, they have a throttle cable instead that...
Symptoms of a Bad or Failing Flexible Clutch Hose
Common signs include difficulty shifting, low clutch fluid, and feeling no resistance at the clutch pedal.
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...


Related questions

Q: My Dodge Neon is misfiring on cylinder #4. The Check Engine Light is on, code is P0304.

A misfire can can also be caused by a vacuum leak, a wiring problem, a faulty fuel injector, a bad electrical connector, or any number of other causes. It would be best to pull the codes that are causing the...

Q: I replaced the output shaft sensor. Do I need to reset the code?

Try removing the battery cables and letting the computer sit for about 1 minute and then hook up the cables or if you have a scanner that can erase the codes. This will clear the engine light and codes to...

Q: Two codes coming up: P0449 & P0455

The most likely cause for these two codes is that the emissions control evaporative canister vent solenoid needs to be replaced. You may also want to check your gas cap to make sure it does not leak; it may be...