2006 Liberty Sport 3.7 EVAP system nightmare. Seeking info, suggestions, help.

I was having a similar issue a couple years back where my ‘06 would die on start after driving it for a while. I replaced the cap, which didn’t seem to fix anything. Then I discovered some of the hosing from the EVAP system was worn down to the point where it was leaking. I think one of them runs really close to the battery tray and it had rubbed right down. I just used some PVC electrical tape on the rub spots and it has been fine ever since. It’s a total manufacturer defect in my opinion.

Blackrose said:

I was having a similar issue a couple years back where my ‘06 would die on start after driving it for a while. I replaced the cap, which didn’t seem to fix anything. Then I discovered some of the hosing from the EVAP system was worn down to the point where it was leaking. I think one of them runs really close to the battery tray and it had rubbed right down. I just used some PVC electrical tape on the rub spots and it has been fine ever since. It’s a total manufacturer defect in my opinion.

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Yes, I had that happen as well. Worn through on the bottom. The dealer told me I had to replace the solenoid, so they missed it.

@JeepSpace Any recent updates since June?

I ask because my P0456 code remains, tags expired in May (still drive it everyday shhh), and I threw in the towel so it's back at the shop again today. I spent $1,035 two weeks ago there (haven't had the time with life lately) replacing the charcoal canister and vapor leak detection pump BOTH with Mopar parts. Labor is not cheap where I am. CEL came back on last Friday, same code, and they're smoke testing again now for free. If I resolve all this once and for all I'll do my own standalone post with part #'s, etc. I have a journey like you since ~2017 haha.

I'm dealing with similar issue on another post about my 06 EVAP canister quick connector. Let me clarify about the white vacuum leak detection pump that attaches to the canister with a sometimes leaking o-ring... It is (not) on the 2006 type canister. 2006 has the black pump shaped like a flying saucer that is on a bracket near the canister.
I too am chasing the leak issue. When I had (4) XJs, it was always easy to fix an EVAP issue. This KJ is a pain. I need to fix it before going to the dealer for the REAR ARMS recall (the prior owner didn't do it). Dealer claims they have to do an inspection because of the age of the KJ. I don't want to get started with them about this EVAP leak too.

I had a similar problem where the code said evap canister. I replaced the gas cap and code still came up. Found out that my PCV valve was loose in the intake manifold. Tightened it up and code went away. I am not saying this is your problem but just something to look at!

LONGJEEPOWNER said:

I had a similar problem where the code said evap canister. I replaced the gas cap and code still came up. Found out that my PCV valve was loose in the intake manifold. Tightened it up and code went away. I am not saying this is your problem but just something to look at!

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Oh thanks for this, I’ll give that a try. I replaced my PCV valve prbly 40k miles ago but they’re $15 (Mopar) so why not try again. I got mine to pass emissions test last month after spending all that $$ but then my CEL came back on the week after, same P0456 code LOL. Screw it my registration is current now so I don’t care anymore!

Look at some of my previous posts with my p0456 code on my 04 KJ, It ended up being the plastic piece on top of the fuel pump had tiny cracks - had to drop the tank and purchase a used one from the bone yard since new was no longer available.

adamkrz said:

Look at some of my previous posts with my p0456 code on my 04 KJ, It ended up being the plastic piece on top of the fuel pump had tiny cracks - had to drop the tank and purchase a used one from the bone yard since new was no longer available.

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Nice! That was the original source of my leak too. I call it the “fuel sending unit” (idk if that’s right), since the actual “fuel pump” sits in the tank. Dumbest 2 piece design if you ask me. Did you try to get your old one soldered? Better than throwing it away since it’s a very limited part! And a ‘03 doesn’t fit the ‘04 I’ve tried. It’s a very specific part sadly.

Well I replaced PCV valve over the weekend. Driven about 100 miles since and CEL still on. No dice. I did notice a small split in the hose beyond where it attaches to the valve however… wonder if it’s causing a vacuum leak and thus my P0456.

My other thought is to replace my not-that-old Mopar gas cap w another one just to see.

Any split is not good and will leak. Trim the hose to remove the split if possible. If not, get some fresh hose and replace it.

runfor5 said:

Nice! That was the original source of my leak too. I call it the “fuel sending unit” (idk if that’s right), since the actual “fuel pump” sits in the tank. Dumbest 2 piece design if you ask me. Did you try to get your old one soldered? Better than throwing it away since it’s a very limited part! And a ‘03 doesn’t fit the ‘04 I’ve tried. It’s a very specific part sadly.

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I ended up buying 2 used spares since I plan on keeping my Jeep - You are right how the pump sits in the tank is not like other years with the dumb 2 piece design.

First of all, howdy! I'm a proud KJ owner. Having been a previous WJ owner, I am thrilled to own a KJ.

I too had the dreaded gascap error. I read all the blogs. Replaced the cap, vapor canister purge valve and finally the Evaporative Emissions System Leak Detection Pump (which attaches to the evap canister). The last one I changed was almost the least expensive and fixed the issue. Once I removed the detection pump, I could see it was broken inside.

To replace the detection pump is simple. The hardest part is jacking up the rear or backing it onto ramps. Once you find it, remove the hose and wires attached to it and twist it off pressing the locking tab. The reverse the process for the new pump. Took me about 15 minutes.

I hope this helps anyone else trying to resolve the issue.
Here is a link to the part I purchased on Amazon: https://www.amazon.com/dp/B09BQYPZR3?psc=1&ref=ppx_yo2ov_dt_b_product_details

JeepSpace said:

Hello All,
I've had an ongoing issue with my EVAP system that no one can seem to pin down. I've worked with 3 mechanics, for various prices, expertise, and other reasons, and still no luck. Here's the History.

1. Noticed the vehicle would choke out and have trouble starting after driving a few hours and then stopping to fill up for gas. Vehicle would choke out while starting, but if I tried a 2nd time it would start. Soon after, it started with the Check Engine light and an EVAP code. Came back "Small Evap Leak" code.
2. Mechanic A suggests it could be Purge Solenoid, Evap Canister, or Gas Cap. Suggests I should start with the Cap as it's the cheapest test and fix. Replace OEM Cap from dealer. Problem persists.
3. Replaced Purge Solenoid by battery. Problem persists.
4. Reset Codes. Codes and check engine light come and go. See GASCAP light intermittently now comes and goes.
5. Mechanic B runs codes and gets "Large Evap Leak." Suggests it could be Evap Leak Detection Pump, Evap Canister, or leaks in lines, connections, hoses. Suggests doing Smoke Vapor Evap test first to check for leaks before buying more parts. He also suggested that if I cycled the key when I had trouble starting, to build pressure in pump/system, and then started, that it should help. This was confirmed. Every time I had trouble starting, if I cycled key once first, listened for gas pump to fire and build pressure in the system, and then tried to start it, it would start right up and not choke out.
6. Do Smoke Leak Test and physically inspect all outer components of system. Results find no leaks at all. Mechanic B suggests it could still be something internal to Leak Detection Pump or Evap Canister, and to start with the Pump since it is the cheaper fix. He also suggests it could be Gas Pump, but doesn't think that's the issue or I would be seeing other symptoms.
7. Mechanic A replaces Evap Leak Detection Pump. Problem persists. Mechanic A suggests that sometimes it's still a bad gas caps and to try another.
8. Replace Cap with an after market cap. Problem persists.
9. At this point, I'm still getting random Small Leak and Large Leak codes as well as the GASCAP code, and I am also smelling fumes every once and a while when I'm towing and accelerating hard to keep up speed while going up steep hills. The fumes usually go away after 15-30 minutes and or when the load calms down. Both the codes, check engine, GASCAP, and fumes all come and go. Sometimes it's a week or 2 with no issues or symptoms, and then they will just pop up again. Then it can go another week or so with no codes or issues; so very intermittent. The GASCAP light has become more regular, almost constant now.
10. Take it to Mechanic C to see what he can find. Mechanic C says it's likely the Evap Leak Detection Pump Filter, but that because I didn't replace the Pump and Filter at same time, that the new Pump could be ruined. Suggests I replace Filter and now Pump again, making sure to do the filter first. He also suggests it could be the Fuel Pump or the Gas Tank Sleeve, but that the sleeve should have showed up in the Smoke test.
11. Replace Evap Leak Detection Pump Filter and then the Pump again..... Problem persists.

So that's where I'm at. At this point the only thing I haven't replaced is the EVAP Canister. Any ideas what I should do next or where I should go from here?
Is the Canister the next best thing?
Could it be the pump, the gas sleeve, or something else?
I'm still intermittently throwing both Small and Large Evap Codes, as well as the GASCAP light is on almost all the time, but not quite all, and it still does respond to Cycling the key; that is if I cycle the key once, it never chokes out.
I've wasted so much time, energy, and money on this issue. I would have loved to find someone who knew how to fully diagnose the issue in the first place and hone in on the correct problem. In any case, I'm so appreciative of any help anyone has to offer, suggestions, or to steer me in the right direction. As well, I'm hoping this thread can serve to help anyone else with a similar issue.

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Sorry for the old thread revival... I am currently battling this issue too and have done much of what you did throughout this thread. Smoke tested, no leaks found, thrown OEM parts at it, no dice... constant CEL for evap leak with a frequent gas cap warning as well. Occasionally CEL will go out for a couple days before returning, but since it has gotten cold, it has stayed on.

Just curious if you were ever able to resolve your issue and what it ended up being?

blackshirej said:

Sorry for the old thread revival... I am currently battling this issue too and have done much of what you did throughout this thread. Smoke tested, no leaks found, thrown OEM parts at it, no dice... constant CEL for evap leak with a frequent gas cap warning as well. Occasionally CEL will go out for a couple days before returning, but since it has gotten cold, it has stayed on.

Just curious if you were ever able to resolve your issue and what it ended up being?

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Ironically soon after posting this, I found my solution... I took my Jeep to my mechanic buddy who professionally smoke tested it after I had no luck with my Amazon smoke tester. No leaks detected anywhere. He was stumped. The only evap part I hadn't replaced with OEM was the charcoal canister so I bought a Mopar replacement canister and swapped it out. When I got the old canister out (total pain in the butt thanks to rusted hardware) it wasn't clogged at all so I didn't have high hopes but I drove 300 miles to Illinois and back to visit family last weekend and have been driving 10 miles to work and back all week and no more CEL (had codes for gas cap, small leak, and gross leak/no flow I believe). No gas cap warning light/chime either.

blackshirej said:

Ironically soon after posting this, I found my solution... I took my Jeep to my mechanic buddy who professionally smoke tested it after I had no luck with my Amazon smoke tester. No leaks detected anywhere. He was stumped. The only evap part I hadn't replaced with OEM was the charcoal canister so I bought a Mopar replacement canister and swapped it out. When I got the old canister out (total pain in the butt thanks to rusted hardware) it wasn't clogged at all so I didn't have high hopes but I drove 300 miles to Illinois and back to visit family last weekend and have been driving 10 miles to work and back all week and no more CEL (had codes for gas cap, small leak, and gross leak/no flow I believe). No gas cap warning light/chime either.

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Yeah, that evap canister is a crummy design. I often wonder who was smoking what when this subsystem was designed and why they ain't sharing.

blackshirej said:

Ironically soon after posting this, I found my solution... I took my Jeep to my mechanic buddy who professionally smoke tested it after I had no luck with my Amazon smoke tester. No leaks detected anywhere. He was stumped. The only evap part I hadn't replaced with OEM was the charcoal canister so I bought a Mopar replacement canister and swapped it out. When I got the old canister out (total pain in the butt thanks to rusted hardware) it wasn't clogged at all so I didn't have high hopes but I drove 300 miles to Illinois and back to visit family last weekend and have been driving 10 miles to work and back all week and no more CEL (had codes for gas cap, small leak, and gross leak/no flow I believe). No gas cap warning light/chime either.

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That's awesome! Isn't the Mopar canister (the rectangle big box underneath the car right?) like a $200-ish part? I remember I never did that on mine cus of the cost. Ironic looking back as I spent more than that between smoke testing and other parts thrown at it at the time lol.

Glad you got resolved!! Especially if where you live requires emissions testing.

runfor5 said:

That's awesome! Isn't the Mopar canister (the rectangle big box underneath the car right?) like a $200-ish part? I remember I never did that on mine cus of the cost. Ironic looking back as I spent more than that between smoke testing and other parts thrown at it at the time lol.

Glad you got resolved!! Especially if where you live requires emissions testing.

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No emissions here thankfully but that light and warning chime were getting really annoying

Yep the OEM part was around $250...it stung a little, but weirdly enough, most of the aftermarket stuff that could be obtained in a timely manner was about the same price. I replaced the canister several years ago (aftermarket) and it was a LOT cheaper back then.

Johnny O said:

Dollars to donuts its a bad canister.

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Fill neck check .

I wanted to follow up on this since I had posted about my similar scenario and the solution -- I have put over 1,000 on my Jeep since replacing the charcoal canister with no CEL or gas cap warning chime until yesterday.

Yesterday, out of nowhere, gas cap warning chime started going off and it has been displaying the warning ever since. This morning, after driving approximately 20 miles yesterday with the gas cap warning displayed, my CEL illuminated once again. Obviously is going to be evap related. I'll pull codes real quick...

P0457 loose gas cap, I'm honestly surprised that's the only code...usually it's accompanied with a very small evap leak code.

Gas cap was replaced with both aftermarket and eventually a new OEM when this whole debacle began last year.

Anyway, since I was pulling the codes, I went ahead and loosened then tightened my gas cap back up. Cleared the codes and as soon as I started it back up, gas cap warning chime. So no idea why replacing the canister and literally nothing else made a difference for over 1,000 miles, but it apparently was not the fix. That had me stumped anyway since usually if the problem is the canister it's due to no flow and I was able to blow through the canister with zero resistance. It's also odd that it is detecting such a massive leak, yet multiple smoke tests have shown no leaks in the system and both my little smoker and my buddy's smoker were able to build up pressure in the system while testing.

johnrotondojr said:

Fill neck check .

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I'll just comment that this was not the case for me. I had my entire fuel filler neck out at one point, freshly painted it on the outside, and it had no obvious rust, cracks, etc. Good suggestion though certainly!