Gas cap message

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Puddle Jumper 2.0

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I am getting a message on my dash that says gas cap loose and I know it’s indicating a vacuum discrepancy thanks to the fabulous environmental protection agency in there. Hyper responsibility to worrying about stuff. We actually pump out of the ground and as part of the ecosystem in the first place, but I digress I’ve replaced the gas cap as well as some of my emissions components in the engine compartment. I’ve checked all the hoses by removing them and flexing them repeatedly in multiple directions to look for cracks, and none of the nipples appear to be broken and I’ve replaced the gas cap itself with a Factory gas cap and I’m still getting the same indication I’m beginning to think that the gas tank filler assembly between where you stick the gas pump nozzle in and the gas tank may need replacing and I’m wondering if anybody has had any experience with troubleshooting this part of the system or if you have any other suggestions on where to look for the problem. Thank you to all who reply!!!
 

profdlp

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Have a look at the evap canister. I had the same issue and that fixed it for me. Like you, I started by checking hoses, replacing the gas cap, etc. Then I had that checked and there it was.
 

Puddle Jumper 2.0

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Well, I pulled the canister, checked it for damage, replaced the switch assembly and gasket with a MOPAR part, reset all codes with my scan tool (all 5 of them-all evaporator or GASCAP codes) and the damn “GASCAP” light came on as soon as I started it up….. God Bless the EPA. Do they know we pump oil out of the ground??? It’s not shipped in from Saturn or trans-warped in from another dimension; it’s part of Earths’ ecosystem!!! Yes we should be clean and careful but OMG this is stupid!!! The hoses seemed to be in good condition and fit tightly into place on both the switch and canister connection points. My next step will to put it back up on blocks and remove my rear splash shield and closely inspect the filler tube assembly for the gas tank unless anyone has a better idea. Also, the purge control solenoid up by the battery is a new MOPAR part and no damage to vac lines up there either….. thanks again to all who respond or simply feel my pain!!!
 

Puddle Jumper 2.0

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Also, I am going to replace the fuel pump assembly and will be dropping my gas tank as a part of this evap BS and would like a definitive answer as to whether or not I have a fuel filter in line anywhere. I use moparpartsgiant.com for part number research and parts as well and I have tried every iteration of the term "Fuel filter" I can come up with and so far no dice! is there a filter built into the pump assembly? also what the heck it the "thing" mounted to the front center of the fuel tank just above the rear diff? its held in place by a steel bracket and 2 10mm nuts. Should I consider replacing it while I have the tank down??
Any other suggestions while the tank is out???
 

DadOSix

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Well, I pulled the canister, checked it for damage, replaced the switch assembly and gasket with a MOPAR part, reset all codes with my scan tool (all 5 of them-all evaporator or GASCAP codes) and the damn “GASCAP” light came on as soon as I started it up….. God Bless the EPA. Do they know we pump oil out of the ground??? It’s not shipped in from Saturn or trans-warped in from another dimension; it’s part of Earths’ ecosystem!!! Yes we should be clean and careful but OMG this is stupid!!! The hoses seemed to be in good condition and fit tightly into place on both the switch and canister connection points. My next step will to put it back up on blocks and remove my rear splash shield and closely inspect the filler tube assembly for the gas tank unless anyone has a better idea. Also, the purge control solenoid up by the battery is a new MOPAR part and no damage to vac lines up there either….. thanks again to all who respond or simply feel my pain!!!
The only way you stand a hope of finding this leak is by doing a smoke test. A message that fast indicates a larger leak and should show up easily with smoke. A few decent you tubes aboutmaking your own cheap version.
 

DadOSix

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Also, I am going to replace the fuel pump assembly and will be dropping my gas tank as a part of this evap BS and would like a definitive answer as to whether or not I have a fuel filter in line anywhere. I use moparpartsgiant.com for part number research and parts as well and I have tried every iteration of the term "Fuel filter" I can come up with and so far no dice! is there a filter built into the pump assembly? also what the heck it the "thing" mounted to the front center of the fuel tank just above the rear diff? its held in place by a steel bracket and 2 10mm nuts. Should I consider replacing it while I have the tank down??
Any other suggestions while the tank is out???
Why change the fuel pump if you are not having trouble here?

No replaceable fuel filter exists.
 

Puddle Jumper 2.0

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I figured that was the case. At 190K our liberty has been getting a lot of new parts. We own it and it is my wife’s primary transport so I don’t want it breaking down on her and then dealing with a failed component. Plus, if I take the time to pull her car out of service to work on it, I generally replace everything I have to go past for the repair unless it was done recently. I just got done replacing struts and the factory non-grease-able/non serviceable upper ball joint and all the associated rubber bushings led to the entire front end getting rebuild: struts, upper/lower control arms, hub assemblies, inner/outer tie rods, CV shafts and with the extreme wear I saw with all those ball joints n rods I also did the rear suspension springs and all! It rides like we just drove it off the dealer lot again!!! The transmission went a about two years ago now and that repair came with a new exhaust (if I have to take it off to get a repair done I do not put old parts back in), front and rear drive lines, wheel bearings and seals in the rear axle, all fluids in everything including the brake system which everything got replaced except the ABS module (well…… it wasn’t in the way so I let it stay) and new engine/transmission wire harness(yes I found one still in the factory sealed dust covered box). The harness was not an item I planned on replacing but the main plug on the top of the transmission crumbled into pieces when I unplugged it as I pulled the transmission. Unplugging a harness doesn’t usually meet my criteria for “if I have to take it off I don’t put old parts back” but there is no way that plug was gonna stay in place and dry nor was I going to use a harness from a junk yard that would likely be in similar shape! I am not independently wealthy (chemotherapy RN) so I pickup extra shifts to pay for the project then knock it out. I just will not take the same mess apart several times and replace components as they fail. Besides if one thing is worn to the point of replacement the associated parts are not far off from failure either. Now, dropping the tank is not as involved as some of the other work I have done but in this case considering the milage I have on the original pump-filter-sending unit I’m going to put a new MOPAR unit in. What got this idea in my head was o post from another member about the nylon rim of the pump assembly being damaged and compromising tank pressure, causing the same codes I am getting (yes I know pretty much all the evap-codes pop on a leak of anykind). He included pictures of what he found when he dropped the tank (which admittedly I may not find) and I also noted that every single evap hose in the back is easily accessed with the tank down! I will take and much appreciate the advise to smoke test it so ancillary hoses and connections can be troubleshot but, the tank is out so…… I am very likely to put a new filler neck assembly in too. It’s still available from MOPAR and we have to be super careful when pumping gas as the pump auto shut off no longer automatically shuts off like it once did, so something in there is not working right. It has been acting up by puking gas’s out but I have never had an evap code pop until recently. Even though I don’t have to remove it, access will be peak with no tank in. Again, THANK YOU to all who take time to read and respond!!!
 
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KJowner

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Now I'm a diesel man so no evap system here but I'm wondering if like my EGR system if this BS isn't best bypassed? I wonder what actually monitors it??
 

Puddle Jumper 2.0

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Good idea!!! I will likely do that just in case (hopefully I will get another 190K or more out of the new one too!!). I Will use a painted piece of 18 ga sheet metal and silicone/calk over hole in rear cargo pan just to keep it air tight for exhaust fumes.
 

YavapaiLibertyGuy

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Had the gas cap code on my 07 and turns out it was the EVAP system test pump failing. I think that part is around $30 and not a difficult fix, worth a shot.
 

cas123

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Is it PO456? I replaced my gas cap twice- the second one was a MOPAR to make sure. Then I started cleaning the gas cap with alcohol- the o ring degrades and affects the seal. Someone said to put vaseline on the o ring seal would help and it has. I have not had the code for months now. Not saying the same problem you have, but cleaning the area makes it go away and vaseline has kept it off for months, so I do believe mine is the gas cap. Just poorly made.
 

cas123

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Also, I am going to replace the fuel pump assembly and will be dropping my gas tank as a part of this evap BS and would like a definitive answer as to whether or not I have a fuel filter in line anywhere. I use moparpartsgiant.com for part number research and parts as well and I have tried every iteration of the term "Fuel filter" I can come up with and so far no dice! is there a filter built into the pump assembly? also what the heck it the "thing" mounted to the front center of the fuel tank just above the rear diff? its held in place by a steel bracket and 2 10mm nuts. Should I consider replacing it while I have the tank down??
Any other suggestions while the tank is out???
There is a filter on the tank. I ordered one from Rock Auto but sent it back when I saw all the trouble it takes to change it. I cut the rug in the back truck area to get to the access panel and it is all sealed shut which would take a ton of work to remove. Either that or drop the tank. I have on 04. This depends on the year as they changed the setup over the years. What year are you dealing with?

This is the one I ordered- Autozone has them. The OEM part numbers include 52100402AE, 52100402AF, and 52100402AH. MOPAR says : "Fuel filter replacement is not a part of the normal maintenance on this vehicle. The main fuel filter and inlet fuel filters are extended-life parts that would only be replaced after diagnostic tests indicated that excess contamination existed in the fuel tank. The filters would be replaced after having the fuel tank cleaned. The main fuel filter is located at the front of the fuel tank. To replace it, relieve the fuel system pressure and disconnect the cable from the negative battery terminal. Check if the vehicle has a Fuel Pump access cover and remove it if present. If not, the fuel tank must be lowered to gain access to the fuel pump module. Clean the area surrounding the fuel lines and disconnect the fuel lines from the top of the upper section of the fuel pump module. Raise the rear of the vehicle and support it securely on jackstands. Disconnect the third fuel line and release it from the retention clip on the chassis. Remove the fuel filter electrical ground strap from the fuel tank mounting strap. Remove the filter mounting nut and remove the filter. Position the new filter/lines in place and install the carpet and cargo hold-down clamps if applicable. The inlet fuel filter is attached to the bottom of the lower section of the fuel pump module inside the fuel tank. Remove the fuel pump module and then remove the filter from the lower section by prying the two release tabs with two small screwdrivers. Clean the filter opening on the lower section and snap the new filter into place".

LUBER-FINER Fuel Filter G1057- Rock Auto number​


I was going to change it because I did a tune up and still some problems when going up hills so I thought fuel filter. But found some other issues - leaking antifreeze dripping onto cylinder4 and fixed that, then Sea Foam has made it run a lot better.
 
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cas123

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It is. They had an access panel on the early KJs. I found one at a junkyard.
They have this stupid coating to seal them. I read somewhere to use dry ice to make it shatter. That was my plan to open it up. Heat might work- but the gas tank is underneath it, so that heat can radiate and cause a problem. I saw one tank that was melted on top and not sure if it was from welding or trying to get the access panel open. Why make an access panel and seal it shut like that? Totally unnecessary.
 

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