My P0456 code came on this morning, and I was wondering ways I could troubleshoot this. Also, what things can an evap leak cause? Is it still safe or healthy for my engine to drive with this code on?
P0456 Code
- Thread starter DropTopDon
- Start date
Bloodlines33
Member
Check your gas cap first. Then look at all the EVAP hoses and connections. Good luck on your search! I'm not a mechanic so don't trust me but from what I've read it doesn't seem to hurt or damage the engine.
I've got the same code. I've been driving it awhile anyway. I haven't had the time to do a smoke test and I don't have a smoke machine. I tried to find a place to rent one but was unsuccessful. I was also going to start with replacing the gas cap.
Before you jump into replacing the gas cap; remove and inspect the seal and the sealing surface of the gas filler neck. Wipe the filler neck sealing surface and the seal for the gas cap; reinstall the cap and reset the code.
I have done this with positive results, but after a while the seal dries out and the cap will need to be replaced.
IF the code comes back then replace the cap.
I have done this with positive results, but after a while the seal dries out and the cap will need to be replaced.
IF the code comes back then replace the cap.
John Scoggins
TJ Enthusiast
Like everybody suggested start with the cap, if that does not clear it check all the connectors and flexible lines, pay attention to the one under the drivers footwell, they usually rot out along with the vacuum connection from the purge valve to the intake manifold. Another place to check is the purge valve itself, you should not be able to blow through the purge valve when it is deactivated.
You can get a pretty good smoker from Amazon for under 100 bucks (if you have access to an air compressor) that will help if you need it.
You can get a pretty good smoker from Amazon for under 100 bucks (if you have access to an air compressor) that will help if you need it.
I’ve been getting a p0456 code. I changed the gas cap, then I checked the lines all the way back to the tank and they looked good. They code came back. I then took it to a shop where they smoke tested it, they told me it looked like the charcoal canister. So then I changed the charcoal canister, and while I was in there I just changed the leak detection pump in the passenger side rear fender well. I also checked all of those hose connections and they looked good. It came back about 4 days later. I then changed the purge valve under the hood, thinking that would be the last thing I would have to do without dropping the tank. Well, it came back on a week later. I just bought a new fuel tank gasket and fuel pump nut. I’m thinking this will be the last thing it could possibly be. I’ll update this once I drop the tank and find out. I might just buy the smoke machine at this point.
I got this one for $122 total about 4 months ago. Worth every penny. This thing really pumps out the smoke, has its own regulated air pump, and made finding the vacuum leak very easy. The price seems to have gone up with this particular seller but when I found this one for $114 (before taxes) a lot of other sellers were asking about $145...so look around.
https://rover.ebay.com/rover/1/711-...0001&campid=5337789113&icep_item=254611458927
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Update! I made a home made smoke machine I saw on youtube. Tried it out last week and could see smoke coming out from on top of the fuel tank. Dropped it yesterday after watching half a dozen youtube videos, and found the previous owner hade done some sketchy patch job on the fuel tank vent. Smoke tested it again once it was down, and confirmed where it was coming from. I went and bought some epoxy and covered the entire area. It definitely isn't pretty, but I believe I finally got it. Let it dry for around 4hrs, and took it for a good test run. OB2 scanner shows no pending codes. Finally!
James Brewer
Member
Hey you need a fuel tank?? I just swapped my 19 gallon tank out with a new 31.5 gallon tank..its clean has the lock nut just need to swap over your fuel pump and hoses....OH another good idea while your tank is out...I cut a hole out in the rear floor board and made a trap door so that in the future replacing fuel pump lines etc I don't have to drop tank...