Check engine light p0456

rgory · Post by **rgory** » Mon Sep 08, 2014 9:20 pm

Ok, so I have done a bunch of reading on here and Dodgetalk and have not found a solution that works. About a year ago I got a check engine light on, when I checked with the key trick it was for p0456-small evap leak. I lived with it for a while thinking it may have been a loose gas cap. I checked for cracked hoses and found nothing. I lived with for a while and the. Bought a new gas cap from the dealer for $25+ bucks. When that didn't work I took into a local shop the mechanic from work recommended. They replaced the filler neck with a mopar one and sent me on my way. The light came back on after 2 weeks, when I took it back they said I left the gas cap loose. They cleared the code and sent me on my way. It came back. I finally got tired of it last month and took it to a shop next to where I work. They leak checked it and said that nothing was obvious but they thought it was the leak detection pump, I paid for the pump and they put it in for free. Last week the light came on and then it read gas cap in the odometer, I got out and the cap was tight. Took it to them and they thought it was a fluke, cleared the code and this morning it is on again. I have noticed it will only happen after it sits all night and the temperature drops. It does not come on in the middle of trip only when I first start in the morning. The smoke tested it again today and said nothing was showing. They are leaning towards a purge solenoid but they are not sure, I am kind of fed up with the silliness and just want it fixed.

Any ideas?u

cruz · Post by **cruz** » Mon Sep 08, 2014 10:00 pm

Is it affecting performance or just an annoying light. Here is what I found regarding the p0456 code. I'm no good at trouble shooting this computer stuff, but I can look things up in the FSM. Anything specific you want me to look for ?

rgory · Post by **rgory** » Mon Sep 08, 2014 10:40 pm

Thanks Cruz it is a place to start. There does not seem to be any affect on performance, just a nuisance and the remote start will not run if the light on....

Mr.Smith · Post by **Mr.Smith** » Tue Sep 09, 2014 12:56 am

"Key trick"??? Enlighten me, It may be useful down the road.

coder · Post by **coder** » Tue Sep 09, 2014 12:43 pm

What year is your truck there is a TBS on a plugged filler neck breather valve on 4G trucks I think?

TwinStick · Post by **TwinStick** » Tue Sep 09, 2014 1:05 pm

If you still have your old gas cap, carefully take it apart, totally apart. Then, seal everything up. Every hole & seam, with silicone or epoxy & wipe off the excess (put back together before it dries) so it will still screw on when dry. NOTE: it will no longer have the "click" feature when tight. Pull the + battery cable off for 30 min. Put it back on. Put the fully dry & cured gas cap back on. See if light comes back on. If it does not, then the gas cap was the problem. If it does come back on, then it is something else.

I had to do this with my 2000 Dakota & my 2004 2500 QC. Dodge had a huge batch of bad gas caps. They will not admit to it though. I went through 7 on my Dalota and 6 on my 04' 2500. I was so sick of it, thats what i did to narrow it down myself. Otherwise, it would have cost me thousands of dollars to have them diagnose & fix that problem 13 friggin times !!! I have been through 1 already on my 08' Wagon with 34k on it.

rgory · Post by **rgory** » Tue Sep 09, 2014 1:06 pm

Sorry, the truck is a 2007. There is a TSB for an intermitent p0456 but it does not apply for my build date of 12/2006.

"Key Trick"- Cycle Ignition from off-on three times within 10 seconds and the code will show up in the odometer. Note only go to the on/accessory position not all the way to start. I checked the purge solenoid and it is holding vacum as it should and I double checked all of the evap hoses which seem to be in good shape. I am considering throwing a solenoid at it and the hoses so I can focus on other culprits.

rgory · Post by **rgory** » Tue Sep 09, 2014 1:08 pm

I will dig out the old gas cap and try sealing that guy up as well.

rgory · Post by **rgory** » Tue Sep 09, 2014 1:10 pm

I will dig out the old gas cap and try sealing that guy up as well.

bajaben48 · Post by **bajaben48** » Wed Sep 10, 2014 12:50 am

rgory, I get that that same code about every 6 or 7 days. I now keep my code scanner in the truck so i can erase the code when it pops up. I also had the gas cap light come on as well. I have also put in an aux gas tank that I ran directly to the filler neck. I also put a vent line from the aux to the filler neck, so there is a fill line a and vent line coming off the aux to the filler neck. So when I sarted geting this code about 4 months ago I attributed to the aux tank. But it only happens on really hot days so I think its when the fuel gets hot and "gases" off and creates a lot of fumes. I also thought it it could be the purge solenoid but I dont know were it is to check it.

bajaben48 · Post by **bajaben48** » Wed Sep 10, 2014 12:54 am

Quick side note, I have had my aux tank I for almost 20 months. So I cant say its the aux tank for sure

rgory · Post by **rgory** » Wed Sep 10, 2014 6:25 am

That is interesting because I can contribute my light to changes in temperature as well. It seems whenever it cools off I get the code showing up at the next cold start. Although the seal on the purge solenoid is holding I am going to replace it as the cost is minimal. The solenoid is located next to and below the battery it has a wire harness and 2 little tubes going to it.

bajaben48 · Post by **bajaben48** » Wed Sep 10, 2014 9:25 am

Ok. I will loom at mine and see if I can find anything unusual.

bigblackdodge · Post by **bigblackdodge** » Fri Sep 19, 2014 9:59 pm

Would a bad purge solenoid contribute to starting problems? I've always had an intermittent problem that when I start the truck, it turns over more than a few times but then starts. It always starts but just has to turn over for a few seconds. I just got the same code and cleared it with my scanner....

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bajaben48 · Post by **bajaben48** » Fri Sep 19, 2014 11:14 pm

Not sure. I dont see how but I am not an expert or anything.
I will not the code did come up again and the temp change was dramatic like in the past

rgory · Post by **rgory** » Tue Sep 23, 2014 7:33 pm

The light came back on so back it went... They smoked it again and could smell a small amount of gas from on top of the tank. They called and said it appeared to be the o ring around the sending unit. I am hoping this finally kicks it.

Rg

rgory · Post by **rgory** » Thu Sep 25, 2014 8:04 pm

So when they pulled the fuel pump they noticed a crack in the rim of the fuel pump. $600 later and I hope the light is gone for good.

cruz · Post by **cruz** » Thu Sep 25, 2014 8:23 pm

rgory wrote: $600 later and I hope the light is gone for good.

Wow, was that $600 just for the fuel pump replacement or for everything that you have done ?

rgory · Post by **rgory** » Thu Sep 25, 2014 10:01 pm

$600 total, which includes $285 for the pump itself and 3 hours of labor to cover everything. These guys were great to deal with, when I first brought it in they were upfront and told me they were not positive the Leak detection pump would fix it. No diagnosis fee or install, I just had to buy the $30.00 part. They didn't charge me the two times I brought it back or for the purge solenoid. I thought it was good when you consider the book time for replacing the fuel pump is 2.2 hours and they did that as well as smoke it several times.

Rg

cruz · Post by **cruz** » Thu Sep 25, 2014 10:06 pm

Did they have to take the bed off ? $600 for everything they did seems very fair.

rgory · Post by **rgory** » Fri Sep 26, 2014 7:25 pm

They thought it would be easier to loosen the bed up and prop the front of it up 8 inches or so than removing the skid plate and dropping the tank. They loosened the fuel filler neck but all of the lights were unaffected.

TwinStick · Post by **TwinStick** » Sat Sep 27, 2014 11:31 am

"$600 later and I hope the light is gone for good."

"They loosened the fuel filler neck but all of the lights were unaffected."

So, did this fix the problem ? I'm confused.

rgory · Post by **rgory** » Sat Sep 27, 2014 7:44 pm

Seeing how the pump was visibly cracked this had to solve the issue. They took the pump out from the top of the tank without dropping the fuel tank. Instead they propped up the bed and got at it that way, they only had to loosen the bed bolts and the filler neck to lift the bed up.

adeluca73 · Post by **adeluca73** » Tue Sep 30, 2014 8:22 pm

So the fuel pump lip crack was causing a loss in vacuum, which threw that engine error code? So is everything done & fixed?

rgory · Post by **rgory** » Tue Sep 30, 2014 8:54 pm

So far so good, no light. There was a member on DT that had also reported a cracked fuel pump flange causing the code and it certainly seems like a smoking gun. If anyone has a persistent code and nothing obvious shows up when a smoke test is performed I would suggest looking at the pump.

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