Help to pass inspection: P0456 small evap leak - JeepForum.com
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post #1 of 49 Old 05-25-2020, 03:56 PM Thread Starter
fmradio516
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Help to pass inspection: P0456 small evap leak

The fun never ends! Ive had this code for a while and when it first started, i brought it to a shop and they said they did a smoke test and its coming from up in the gas tank and it wasnt necessary to fix it as the car only needed safety only inspection in Massachusetts.

Fast forward and now im going to be moving to Connecticut and they are MUCH stricter. I think the car needs to be older than 1995 for a safety only inspection. So ill need to do something about this. I cleared the code a few days ago and drove it a bit. Kept checking to see if all the Monitors changed to "Ready" and as soon as the last one became ready, the CEL came on again with the evap code. So im not gonna be able to pass inspection in CT.

I have already replaced the gas cap with a new one, so looking for any other possibilities. Any ideas?

Side question: Does anyone know the exact drive cycle needed to make all the tests "Ready" I basically drove 60 highway miles with very little "city" miles and it took a bit for all the tests to be ready. Should I have done more city driving?

Thanks y'all!


2004 Grand Cherokee Limited that I dont know much about :)
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post #2 of 49 Old 05-25-2020, 04:05 PM
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I do not think all the drive cycle;s will complete with a code. Dem puters be smart.
Will Conn require ALL monitors to be set? Some states allow 1 or 2 to be not ready.

What year and engie is the jeep?
I will look at details and TSB's for you.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #3 of 49 Old 05-25-2020, 06:20 PM Thread Starter
fmradio516
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Originally Posted by jtec View Post
I do not think all the drive cycle;s will complete with a code. Dem puters be smart.
Will Conn require ALL monitors to be set? Some states allow 1 or 2 to be not ready.

What year and engie is the jeep?
I will look at details and TSB's for you.

The CT emissions site doesnt specify. Only says "Required amount"

Its an 04 I6. Thank you!!!

2004 Grand Cherokee Limited that I dont know much about :)
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post #4 of 49 Old 05-25-2020, 06:23 PM
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Well good news, CT we currently have a 180 day extension on emissions. I had the same problem. Fogged it, ended up being a hose in the back my the evap pump. While fixing the leak we also replaced the pump as it seemed that it wasn't engaging properly too.
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post #5 of 49 Old 05-25-2020, 07:16 PM Thread Starter
fmradio516
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Originally Posted by TastyWheatLoaf View Post
Well good news, CT we currently have a 180 day extension on emissions. I had the same problem. Fogged it, ended up being a hose in the back my the evap pump. While fixing the leak we also replaced the pump as it seemed that it wasn't engaging properly too.
Good to know! Is replacing that pump a big job?

2004 Grand Cherokee Limited that I dont know much about :)
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post #6 of 49 Old 05-26-2020, 08:05 AM
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here is the LDP pump location.
The poster said a hose was the problem - anyway I would look here at all hoses.
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When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #7 of 49 Old 05-26-2020, 08:56 AM Thread Starter
fmradio516
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here is the LDP pump location.
The poster said a hose was the problem - anyway I would look here at all hoses.
Thanks!

2004 Grand Cherokee Limited that I dont know much about :)
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post #8 of 49 Old 05-26-2020, 09:07 AM Thread Starter
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Had a thought. If I have a loud whistle noise for the first few mins after starting the car (not a screeching belt), people have recently said that its probably my intake manifold gasket. Could this be the answer to my P0456 code?

2004 Grand Cherokee Limited that I dont know much about :)
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post #9 of 49 Old 05-26-2020, 10:38 AM
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I'd look at the P0456 separately from intake leak. Think of the evap system as just that, a sealed system not only with the components Jtec showed but there are also rubber hoses going from that to the hood and into the intake. Luckily the ones running the rest of the way along the body are steel lines so those should be good. Basically no fuel fumes should escape when the pump pressures the system up. One little crack in a hose and it'll trigger that code. Check all the rubber hoses. When I did mine two years ago I went ahead and dropped the tank so I could see everything and they were mostly in bad shape just splitting at the connection. One of them split where it goes into the intake could cause the whistle for example but I would think it would be constant and not go away once up to temp. If you can get the code to go away you get your test done at least and worry about the whistle later if it's still there. Inspection shop won't care about it if it's not obvious or triggering CEL.
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post #10 of 49 Old 05-26-2020, 10:52 AM Thread Starter
fmradio516
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I'd look at the P0456 separately from intake leak. Think of the evap system as just that, a sealed system not only with the components Jtec showed but there are also rubber hoses going from that to the hood and into the intake. Luckily the ones running the rest of the way along the body are steel lines so those should be good. Basically no fuel fumes should escape when the pump pressures the system up. One little crack in a hose and it'll trigger that code. Check all the rubber hoses. When I did mine two years ago I went ahead and dropped the tank so I could see everything and they were mostly in bad shape just splitting at the connection. One of them split where it goes into the intake could cause the whistle for example but I would think it would be constant and not go away once up to temp. If you can get the code to go away you get your test done at least and worry about the whistle later if it's still there. Inspection shop won't care about it if it's not obvious or triggering CEL.
yikes, dropping the tank... im probably not equipped to do something like that. Is there a way to identify which hoses in the engine bay are the ones for the evap system? I could definitely check those as well as the ones in the rear wheel well.

2004 Grand Cherokee Limited that I dont know much about :)
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post #11 of 49 Old 05-26-2020, 10:54 AM Thread Starter
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anyone know an easy way to do a homemade smoke test? Few puffs of cigarette smoke into the throttle body??

2004 Grand Cherokee Limited that I dont know much about :)
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post #12 of 49 Old 05-26-2020, 11:41 AM
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Originally Posted by fmradio516 View Post
anyone know an easy way to do a homemade smoke test? Few puffs of cigarette smoke into the throttle body??

I just resurrected this thread on the evap issue.



https://www.jeepforum.com/forum/f310...p0442-4351091/


There is a video there on how to make a homemade smoke machine, if you are are so inclined. (A cigarette will not work.)


I'm going through the same issue currently, needing to get my WJ inspected in NJ. If anyone has some good shop recommendations and estimates of cost to repair the evap lines in Central NJ, it would be much appreciated.

2003 WJ Overland 4.7 H.O.
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post #13 of 49 Old 05-26-2020, 12:01 PM
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I remember it took me a long time to figure this out too...Turned out to be that my filler neck was rusted in a certain spot allowing vapor escape.

Joe
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post #14 of 49 Old 05-26-2020, 12:11 PM
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Quote:
Originally Posted by fmradio516 View Post
yikes, dropping the tank... im probably not equipped to do something like that. Is there a way to identify which hoses in the engine bay are the ones for the evap system? I could definitely check those as well as the ones in the rear wheel well.
Hopefully you don't have to drop the tank the issue is not likely there anyway just something I decided to do while I was at it. Change fuel filter and pump at the same time. Anyway, I'd bet money you just have a cracked rubber hose somewhere. As you are looking into engine bay on the right side is the intake manifold you'll see a couple rubber hoses going to it one of those is for the evap to send the vapors after the system does its pressure test. Just trace it back to where it connects to the metal part. Under the hood part definitely easiest place to start.
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post #15 of 49 Old 05-26-2020, 02:41 PM
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Not hard at all, take off rear bumper, remove driver side rear wheel plastic. And it's right there. Be aware that given it's a new England car, you will encounter some rust back there.
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