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Discussion Starter #1
I've been battling a P0455 Evap system leak error code for a couple of weeks. I usually get 4 to 5 days of driving back and forth to work (22 miles one way) between repair attempts with code reset and the next appearance. The CEL usually appears within a mile of home on a cold engine when it happens. I've replaced the gas cap and have found a couple of cracked hoses that have been replaced. I think I've covered the hoses under the hood well so my next attempt will be to drop the tank and check around there. I've dropped the back of the tank once and found a cracked hose to the carbon canister with the help of a small mirror. It's replaced. I think it's time for a more thorough investigation there. My questions are, is it normal for it to take a few cycles before the system checks for leaks ? Does this time frame point to any one component over the others so that I can start there once I've dropped the tank ? Thanks for the advice.
 

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P0455 is a large evaporative leak somewhere between the gas cap and the purge solenoid. 'Large' meaning probably greater than .020". http://www.obd-codes.com/p0455
Make sure that you have a non-venting gas cap. Use the underhood vacuum diagram label to trace the components, lines and hoses. You shouldn't be able to blow through the purge solenoid with it off. Make sure that the rubber hose connector block to the purge solenoid is secure and fits firmly to the plastic fittings.
You are going about the diagnosis the correct way with a visual inspection for the more obvious cracks, holes or rustouts. Many rubber hoses and components dry-rot and crack at the ends where they push onto a metal line.
It was around this era when Chrysler went from an active LDP (leak detection pump) system to a simpler, passive NVLD (natural vacuum leak detection) system. If the leak detector switch doesn't close with the system under slight vacuum within an allotted amount of time, it means that the system is breached-to-air and an evap leak fault code is triggered.
At the shop we have a smoke machine that will blow a cool, UV-dye containing vegetable oil-type smoke into a sealed evap system under low pressure. You will find the leak at the point where the smoke is exiting. This makes finding these more difficult evap leaks much easier.
 

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Discussion Starter #3
I've been using a hand vacuum pump to check the hoses an connections and trying to work my way through following the diagram. I can pull a vacuum in the hoses leading to the solenoid so I believe it's good. When I try it on the line back to the tank I can't get a vacuum so that's why I'm heading there next. I'll continue with the piece at a time checking. According to the diagram my Stratus has a LDP. The replacement fuel cap is from the dealer. I had read where people had issues with the general aftermarket replacements. Thanks.
 

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The fuel tank is vented to the air through the charcoal canister, so you won't be able to get a vacuum to hold in the tank with the car shut off.
By venting through the charcoal granules, the hydrocarbons will be absorbed into the charcoal and not escape into the air.
If you cap or plug the hose off that goes to the LDP air filter, you should then be able to pull the tank down into a vacuum.
It does help to test one section of the system at a time until you can finally isolate the leak.
 

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Discussion Starter #5
5 days and the code hasn't re-appeared. Keeping my fingers crossed. I replaced 3 more hoses this time. All 3 were cracked from age and one had a definite slit through. All 3 wouldn't hold a vacuum. I was able to pull a vacuum from the service port back through the LDP, canister and liquid separator when I separated them from the tank. I could also pull one in the filler pipe and vent tube separately. I wasn't able to get one if I included the ROV (?) , tank, or control valve in the circuit. Since I had the filler pipe off the tank from dropping it, I don't think I had a good plug there. I think that maybe why I couldn't include the tank. If the code comes back, I know where to head. Thanks for the help.
 

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It usually is cracked rubber hoses. If the slit or crack goes all the way through the hose wall, that was very likely the P0455 culprit.
It only has to be a .020" or more hole to set the large evaporative leak code.
Nice work.
 
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