THE LEGENDARY P00456 CODE.

[LONGJEEPOWNER]

Kept throwing this code for 2 weeks now. It comes and goes. Changed the Emission vacuum pump in the back of the charcoal canister and also changed the gas cap. Was under the Libby and even checked for bad hoses on the back of tank. What next?

 

[LibertyTC]

Did you buy a new Mopar brand gas cap?

 

[LONGJEEPOWNER]

Did you buy a new Mopar brand gas cap?

Yes, very first thing I did.

 

[desertdriver]

Sorry to hear this. This sounds like my struggle last year. Even a smoke test provided no answers. I ended up replacing more evap-related parts, one by one. Gas cap twice, canister, etc. The code went away and then came back each time. The last thing I changed was the molded vacuum harness tube between the purge solenoid and the rear of the Jeep and that seems to have solved it, even though that tube seemed just a little rough but still ok. 10,000 miles later and the code has not returned.

 

[JeepLibertyKK]

Kept throwing this code for 2 weeks now. It comes and goes. Changed the Emission vacuum pump in the back of the charcoal canister and also changed the gas cap. Was under the Libby and even checked for bad hoses on the back of tank. What next?

On my 2012 Liberty, a smoke test revealed it was the black hard-tubing that runs along the firewall. Had a crack at the 45 degree bend. Never would have ‘seen’ it. Required the smoke test at a SMOG shop to find the problem.

TEXT EDIT: Now I'm second-guessing myself. I believe the piping on the back firewall is what was replaced but when I look at where it runs to, I'm not even sure if that's emissions related or brake related. Maybe someone could tell me. I do remember when they handed me then piping, it was rather firm, not flexible like tubing and when I folded it, it bent and partially broke or split. I don't really see anything else like it where I thought thought they showed me, but it has been a while.

 

[LONGJEEPOWNER]

Thanks! I am going to run the smoke test as soon as I receive my order from Ama.