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Discussion Starter #1
Hi all, I change the gas cap on my Breeze with an aftermarket lockable gas cap, thinking that would take care of the check engine light trouble code P0441. A week later, the check engine light came back again with the same code. Please help me in trying to figure out what needs to be replaced. Research says the following could be the possible fix for the P0441 trouble code:

Replace Leak Detection Pump (appears to be a common Chrysler fix)
Repair damaged EVAP lines or canister
Repair open or short in voltage feed circuit to Purge Solenoid
Repair open in PCM purge command circuit
Replace purge Solenoid
Replace vacuum switch
Repair restriction in Evap line or canister or solenoid
Repair resistance in purge connector
Replace PCM

I prefer to just replace the necessary part(s) with a minimum amount of time and money spent. I'm pressed for time because the car needs a smog check prior to registration renewal due in two weeks. My preference is to do this myself as shade tree mechanic.

An evaporative system test for vacuum leak using a smoke machine was suggested by a website. Unfortunately I don't one, nor have access to one. Is this a necessity?

Since time and money is limited, where should I start? Since the leak detection pump is a common fix, should I start with that? How do I know its bad at this point?

Is a visual inspection sufficient enough to see a damaged evap lines or canister? If it is, what is the symptoms of a damaged evap lines or canister?

Should I replace the purge solenoid, and how do I know the purge solenoid is bad?

How do you repair resistance in purge connector?

How do I know my PCM is bad?

Please help, and thanks in advance.
 

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The most common cause of an evaporative leak is dry rotted/cracked rubber vapor hoses after a few years. They seem to crack at the ends where they connect to a fitting more often than along the hose. There is a vacuum diagram label under your hood that shows all the components and the hose/line routing between them.
The leak detection pump (LDP) was replaced more often than it should have been as it wasn't usually the problem. There is a manifold vacuum supply hose to the LDP that often cracked, leaked or became disconnected and would set the code. The LDP would be the first to blame before further investigation. It's usually the simple things that get you.
At work we had a smoke machine that would fill the vapor lines with a cool vegetable oil (with UV dye added) smoke under a couple of PSI. One just had to watch for where the smoke exited in order to locate the leak.
The system must be air-tight. A hole of .020" to atmosphere will set a fault code.
 

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Discussion Starter #3
Imperial Crown. Repairpal seems to agree with you also, because their site mentioned that often, a pinched or disconnected vacuum lines to the LDP may also trigger a P0441 code, instead of the LDP beng bad.

Imperial Crown, I did locate diagram you are referring to, but being a newbie on car repair, I couldn't figure out the exact location of the LDP. The Chilton manual says that the LDP is located by the passenger side of the vehicle, behind the front fascia, and that the headlamp assembly must be removed for access. Is this correct? I tried doing a visual on the general area, and I can't seem to find it.

Thanks again for all your help
 

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The LDP is underneath the right (passenger side) headlamp. The headlamp can be removed with the 2 long torx/7 mm screws. Make sure that you don't turn the headlamp aiming screws by accident.
With the car safely raised, inspect the rubber vapor hoses for pinches, cracks, or loose fitting ends from between the tank to up towards the right front corner.
 

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These would probably be 2 separate and unrelated issues.
First, there is an evaporative vapor leak or LDP vacuum/electrical support problem for your P0441 code.
Second, high NOx would likely be an EGR or cat problem.
I am not familiar with the smog check test procedure in your area, but a malfunctioning EGR would likely show up while the engine was under load (i.e.- a warm engine power braking test). http://en.wikipedia.org/wiki/Exhaust_gas_recirculation
There is a 'reduction' element inside the cat that is dedicated to NOx control. The upstream and downstream O2 sensors are used to test the cat by comparing the amount of oxygen going into a cat to the amount of oxygen leaving the cat. They will not test the 'reducer' portion of the cat that controls NOx.
http://www.howstuffworks.com/catalytic-converter2.htm
 

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Discussion Starter #6
After I turned off the check engine light without doing any repair at all, I took my Breeze for a smog check to narrow down what needs to be repaired. As expected, the car failed due to high ntirogen oxide emissions (NO-PPM). Max limit in my state is 443, and my car is emitting 493.

I have searched for possible fix for high NO-PPM emissions, but I can't seem to reconcile the suggested repairs for high NO-PPM emissions with the suggested repairs for OBD trouble code P0441. My mechanic suggested changing the catalytic converter. Does that sound right?

So, with a high NO-PPM emissions with an OBD trouble code P0441, which course of repair should I take?

Thanks again

ImperialCrown said:
These would probably be 2 separate and unrelated issues.
Thanks again, I'll trust my mechanic then to change the catalytic converter. Hopefully that will take care of the NOx emissions problems. I'll deal with the LDP/vacuum leak at a later time.
 

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Have your technician do some diagnosis before just replacing the cat. It would be a frustrating and expensive guess if that wasn't the problem.
 

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Discussion Starter #8
The Breeze passed the smog check. There are 2 unrelated issues.First, The high NOx emission was fixed by changing the catalytic converter. Fortunately, after market cat converter is still available, so I took that route.

OBD code P0441 was also fixed by replacing a rubber hose that connects to the EGR and changing the purge solenoid valve. Fortunately, the LDP was fine. Purge solenoid valve was a mere $25 from Amazon, so I can live with that. Thanks for all your help.
 
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