If an engine light comes up on your dashboard, and after using a scan tool to read the error, it comes up with a P0455 error code, there are some common causes.
The causes will be the same for Ford, Dodge, Chevy, or any foreign and domestic vehicle.
What is a P0455 OBDII Error Code?
A P0455 Code is an Evap System Large Leak Detected.
The Evap system is a part of emissions and helps stop vapors from the gas tank from escaping into the atmosphere.
A standard Evap system has several components which keep the gas tank sealed and fed fumes back into the engine to be burnt away.
Below are the most common causes and fixes for a P0455 code.
How Is a P0455 Code Fixed?
A P0455 error coed is usually fixed by using a smoke machine that feeds smoke into the Evap system and comes out the leak.
Most mechanic shops will use a smoke machine since it makes the leak much easier to find.
If no smoke machine is available, check all the major components in the Evap system for a leak and replace any suspected bad parts.
Read here for more on smoke machines.
Causes and Fixes of a P0455 OBDII Error Code
- Gas Cap
- Purge Valve
- Evap Canister
A bad or loose gas cap will cause a P0455 and is the most common fix.
Often the cap simply was not put back on, but a bad one can also cause this error.
Tighten the cap; if the code comes back, replace it. If the code comes back again, the problem is elsewhere.
A bad purge valve can cause a P0455 error code.
The purge valve is usually located near the throttle body and will have 2-3 hoses on it.
A purge valve opens and closes to let the fumes from the gas tank be burnt away.
While the vehicle is off, the valve will close, and when the vehicle is running, it will open.
The Evap Canister allows the system to vent when needed.
If the canister goes bad they can cause a leak to appear in the system.
A bad canister can leak causing a P0455 to show up.
The Evap Canister is usually located near the gas tank but be sure to read the manual for the location on your vehicle.
Is it OK to Drive With an P0455 Code?
Yes, it is usually safe to drive with a P0455 Code, but the vehicle may use more gas and not pass an emission test.
If an emission test needs to be done, the problem will need to be fixed, or the vehicle will fail the test.
A P0455 Code will usually not affect the performance of the engine, and the car or truck will continue to operate.
The above are the most common causes for a P0455 code, but of course, it could be something else.
For example, if a gas tank was somehow damaged, creating a hole can also potentially create the same error.
Wiring can also cause an error with a bad connection giving the computer the wrong results.
Most of the time, it is a bad gas cap, but if after replacing it, the code comes back, the Evap Canister Vent Valve would be the next likely problem.
A mechanic with a good scan tool and a smoke machine can tell what has gone bad, which usually costs.
If the Vent Valve is easy to get to, it may be worth replacing once the gas cap has been ruled out.
Keep in mind there are other problems that can cause this error, such as wiring with the below options the most common.
Of course, if in doubt, always take your vehicle to a certified mechanic.