Check Engine Light - Code P0457 Evap Sys

[Bo13mwz]

Greetings everyone:

 

2004 Outback Sedan H6 3.0 , 38,000 miles:

I keep having my check engine light come on and it keeps reading the same code. P0457, Evap System, Gas Cap Loose or off.

Cap is secured and turned 180 degrees after fueling up and using Premium Fuel.

Dealer has tested fuel cap & pressure tested, replaced fuel cap, but yet to no avail, check engine light triggers at 3/4 tank.

Though, I am not being charged for any of this by Subaru dealer, it is getting somewhat irritating, because I don't like the light being on and dropping the car off at the dealer in the morning and picking it up in the afternoon is getting old, even though the dealer is less than a mile away.

Car has no history of check engine light coming on, then at 37,000 miles it started, after feuling up. Have used same gas station since beginning.

If anyone has any suggestions or happens to be a Subaru Tech, your input will be greatly appreciated. I am wondering that even though it is reading this code, that maybe, it might be another area(sensor,relay) that might be triggering this code incorrectly, Or maybe their is a Subaru bulletin out as a subsequent to an original bulletin that maybe this dealer is not looking at or aware of , or just overlooking ?

Not trying to insult anyones intelligence, just trying to solve issue.

 

Thank you in advance.

[subaru DR]

Well there are a couple of things you need to look at. there is a fuel tank pressure sensor on the gas tank, sometimes these go bad and tell the computer there is no fuel pressure when there is. the easiest way to ck is to see if the select monitor is reading pressure. This is where it is a little tricky. If the sensor is not reading pressure either the sensor is bad OR the tank has a leak. There is a special subaru tool that can be installed on the the tank where the cap goes. You block of all the the hoses and pressurize the tank to make sure it holds. If the tank holds presure and the sensor does not read, replace hte sensor. You are not out of the woods yet. If the sensor does read and the tank holds pressure, you need to look at the hoses or canister. These hose go from th tank to the canister and to the engine. the best way to ck these is with a smoke machine. you plug each line and blow smoke into it, you then ck for cracks in the lines. The main reason for this code is that the computer senses that for some reason it cannot hold pressure in your fuel tank. You need to find out why. There are some other things you can ck, but try these first . This code, unfortunately is a huge pain in the butt to diagnose because of the amount of hoses, solenoids and components that can affect it. If you need more help LMK

 

The SUBARU DR.

Darin

Greetings everyone:

 

2004 Outback Sedan H6 3.0 , 38,000 miles:

I keep having my check engine light come on and it keeps reading the same code. P0457, Evap System, Gas Cap Loose or off.

Cap is secured and turned 180 degrees after fueling up and using Premium Fuel.

Dealer has tested fuel cap & pressure tested, replaced fuel cap, but yet to no avail, check engine light triggers at 3/4 tank.

Though, I am not being charged for any of this by Subaru dealer, it is getting somewhat irritating, because I don't like the light being on and dropping the car off at the dealer in the morning and picking it up in the afternoon is getting old, even though the dealer is less than a mile away.

Car has no history of check engine light coming on, then at 37,000 miles it started, after feuling up. Have used same gas station since beginning.

If anyone has any suggestions or happens to be a Subaru Tech, your input will be greatly appreciated. I am wondering that even though it is reading this code, that maybe, it might be another area(sensor,relay) that might be triggering this code incorrectly, Or maybe their is a Subaru bulletin out as a subsequent to an original bulletin that maybe this dealer is not looking at or aware of , or just overlooking ?

Not trying to insult anyones intelligence, just trying to solve issue.

 

Thank you in advance.

[Bo13mwz]

Thank you for your response. The Subaru dealer says that the system is holding pressure. Yes, it does seem like it could be just about anything as I went through a similar episode with a Toyota.

 

I guess one of my major questions should have also been, Can I do permanent damage of any kind if I keep driving it ? and am I going to brake down on the side of the road eventually, because of this code ?

I am really glad I purchased the extended bumper to bumper warranty.

 

Going to print your response and provide it to tech, as he is open minded and does not mind input. It cant hurt.

 

If you come up with anything else, please feel free.

 

Thanks,

[subaru DR]

You can drive it forever without aproblem

 

Darin

 

Thank you for your response. The Subaru dealer says that the system is holding pressure. Yes, it does seem like it could be just about anything as I went through a similar episode with a Toyota.

 

I guess one of my major questions should have also been, Can I do permanent damage of any kind if I keep driving it ? and am I going to brake down on the side of the road eventually, because of this code ?

I am really glad I purchased the extended bumper to bumper warranty.

 

Going to print your response and provide it to tech, as he is open minded and does not mind input. It cant hurt.

 

If you come up with anything else, please feel free.

 

Thanks,

[Bo13mwz]

Just in case anyone else has the same issue?

The culprit was a Charcoal Canister.

Yes, I know the code doesnt even come close, but dealer replaced canister at his expense and check engine light never came back on.

Damn thing is located in a bad place, any type of debris that kicks up can puncture canister, especially since it is under trunk on passenger side right behind r/r tire.

Thanks everyone.

[Setright]

And thank you for posting the solution!