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Troubleshooting OBD Code P0441 on 97 Plymouth Breeze

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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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Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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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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Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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16,980 Posts
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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Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
Joined
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16,980 Posts
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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Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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16,980 Posts
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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