Best Place For Evap Leak Test

profdlp

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Is the dealer a good place for a P0456 code diagnosis? I live in a county with this dumb stupid eCheck:


(If I lived about two miles south or west of where I am I would not need it as I would be in a different county.)

I renewed my tags for two years about a year ago and thought I was safe for another year. Just got a notice that my tags are suspended until I get the test, which I won't pass until the code is gone. Turns out that they put the eCheck on hold during the Wuhan Flu crisis and stopped mailing out notices for renewal. That ended on July 1st and I just now got as letter dated July 2nd telling me I have ten days... (Golly - thanks, Post Office! Took you two weeks to move a letter 142 miles from Columbus to the Cleveland area. I used to walk ten miles a day without even trying...)

If not the dealer, any type of place you would recommend? I know you're not familiar with individual shops near me if you don't live here, but neither am I - and I need to get this done.
 

JeepJeepster

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I would first check the fuel cap then do a visual on all of the evap hoses connected to the evap canister.

After that, any sort of decent shop should have a smoke machine to check for evap leaks.
 

LibertyTC

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Geez.. What Fun Prof.
We use to have a similar emission testing facility that we called "Air Scare" = scam =$$ It eventually got dropped, so hated by driver's.
They also included a test for pressurization of the gas cap as well.
If cap did not seal properly vehicle was immediately failed, before anything else.
P0456 Evap Leak Monitor Small (.020) Leak Detected can be the cap. Otherwise find a shop with a smoke machine.
Could you drive to a testing facility or local shop & hand them your gas cap, & ask them to test the gas cap pressurization (probably free then) ?
 

profdlp

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I replaced the gas cap with a jen-you-wine Mopar two days after the code popped up. I also reset the code with my wee little gadget. It stayed off for about five minutes and came right back.

P0456 Possible Causes​

  • Missing or loose fuel cap
  • Incorrect fuel filler cap used
  • Fuel filler cap remains open or fails to close
  • Foreign matter caught in fuel filler cap
  • Evaporative Emission (EVAP) canister or fuel tank leaks
  • Evaporative Emission (EVAP) system hose leaking
  • Fuel tank leaking
The new fuel cap should eliminate 1 thru 4. I don't think my fuel tank is leaking as my gas mileage actually improved by 1-2 mpg AFTER the light came on. That leaves the evap canister or evap hose.

Would it make sense to replace the evap hose? I have no problem with replacing any rubber parts I can get to as the Jeep is going to be 15 years old in a few months and I know that stuff doesn't last forever even if lightly driven. (I just turned over 100K a couple months ago.)
 

adamkrz

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You could do a visual of the evap system hoses both underneath and the engine bay, I chased that code for a year - finally dropped the tank and it was the plastic ring on top of the tank - part was no longer available so had to source one from the junkyard, smoke test did not find my leak.
 

profdlp

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^ That is not encouraging. (But much appreciated - that is why I started this to begin with!) If I knew I could take it somewhere and just get it done without getting ripped off I would do it. Sure would not like to have to drop my tank.
 

profdlp

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^ I just checked that and I see a bunch of them starting at around $120. I'd pay that if I had a high probability of diagnosing the problem. (Not sure how you could be sure of that in any way.)

I did go out today and rattle some hoses around. Is the evap canister itself buried way back there just in front of the firewall like I think it is? That looks like it would be a large amount of fun to get to...

I had been planning on a trip to the dealer for a coolant flush, since from what I understand it is the one thing they do well. I also have a tensioner bolt I can't get out. Wonder if they would be swell guys and cut me a deal if I had lots of stuff done at once? (Haha - I amuse myself.)
 

TomB

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Is the dealer a good place for a P0456 code diagnosis? I live in a county with this dumb stupid eCheck:


(If I lived about two miles south or west of where I am I would not need it as I would be in a different county.)

I renewed my tags for two years about a year ago and thought I was safe for another year. Just got a notice that my tags are suspended until I get the test, which I won't pass until the code is gone. Turns out that they put the eCheck on hold during the Wuhan Flu crisis and stopped mailing out notices for renewal. That ended on July 1st and I just now got as letter dated July 2nd telling me I have ten days... (Golly - thanks, Post Office! Took you two weeks to move a letter 142 miles from Columbus to the Cleveland area. I used to walk ten miles a day without even trying...)

If not the dealer, any type of place you would recommend? I know you're not familiar with individual shops near me if you don't live here, but neither am I - and I need to get this done.
Both my Jeep vehicles have the same P0456 codes on them. Chased them each around for the last 2 years.
In the summertime I clear the codes and they come back in about a week. In the winter time the codes will stay off sometimes for a month or two. I usually clear the codes the night before PA. vehicle inspection day. Both pass with no problem.
 

profdlp

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I cleared mine Saturday and it is still off. (Only driven it for two short trips since then.) I may just try that. With my luck it will come on while I'm in the test facility.
 

Aceofspades

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The EVAP monitors don’t run unless you’re between 1/4-3/4 full. (Unless that’s a GM thing)
 

TomB

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The EVAP monitors don’t run unless you’re between 1/4-3/4 full. (Unless that’s a GM thing)
I heard that before but never tried that. Does anyone know if this works with Jeep/ Chrysler vehicles?
Oh how I miss my old CJ-5 with an inline 6 cylinder without all the censors and monitors. Just drive it and enjoy it!
 

SWilliams

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EVAP test for P0456 -
Ignition off. Fuel Level less than 88%. Ambient Temperature between 39 and 109, Close Loop fuel system.
As temperatures change, a vacuum is created in the fuel tank and EVAP system. With the EVAP system sealed, the PCM monitors the Evap System Monitor switch. If the ESM switch does not close within a calibrated time, an error is detected by the PCM. One Trip Fault. Three good trips to turn off the MIL.

While this is commonly a bad cap it can be any part of the system. Anything that can prevent the system from creating a vacuum. For a smoke machine substitute you could go old school. Get a fixed propane grill regulator, they are set to run about 1/2 a psi. Connect that to an air supply and the EVAP port. Let it run a bit to fill the system, now take a spray bottle of soapy water and spray down all the EVAP parts that you can find. Watch for it to start forming bubbles. (I like to use the bubble solution from a dollar store or similar, it seems to make bubbles easier than common dish soap and they hold together better, I use that in the tire tub as well.)
Find the bubbles you found the leak. It can also be an internal leak through the purge valve which you won't see, but you can clamp off the line to it if you cannot find it anywhere else.
 

profdlp

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So my light stayed off for the past six days. I also received a follow-up notice from the friendly e-people saying they had extended the deadline until September 30th. I guess having the testing centers closed for over a year caused a backlog when they finally were reopened. Gee - who could have seen that coming? :rolleyes:

Since the light was off I decided to roll the dice and headed down there on my lunch hour. There was a long line (see above regarding backlog), but as it turns out they added a self-service kiosk. I jumped on that like a hungry dog on a hambone, since it meant I did not have to do the gas cap pressurization part. And guess what - I PASSED!!!

Being a cynic, I figured out this was too good to be true, so I went in the building to ask the guys working there. They all made the sign of the cross and ran me out of the building because of Wuhan Flu dontcha know. Finally some guy in a mask AND plastic visor comes out and tells me I am all set.

Any idea what part this is?

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It was the only thing I could find anywhere that seemed loose.
 

lfhoward

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That looks like your fuel line where it clips to the fuel rail. Any evidence of a small leak? If there was, I think you’d smell gas.
 

profdlp

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No sign of any leak. The hose was still on there, it had just backed off maybe 3/8". I was pretty much grasping at straws at that point anyway.
 

uss2defiant

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make a diy smoker. baby oil and a cheap soldering iron is what people use.
Since you're in the salty region, perhaps one of the lines in the under carriage is bad or even the fuel tank.
 

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