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Dodgerench, ASE Certified Technician
Category: Dodge
Satisfied Customers: 3406
Experience:  30+ years Dodge/Chrysler exp., ASE Master with L1 certification. Driveability/ combustion specialist
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Need help diagnosing p0441 code on 2003 dodge ram 1500

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need help diagnosing p0441 code on 2003 dodge ram 1500
Hi Muddinjeep5252, welcome to Just Answer!.

P0441 is described as a Purge Flow Monitor Failure, which is a bit difficult to diagnose in the field. Chances are very good, however, that your problem lies with the natural vacuum leak detector (NVLD), the actual device used for detecting evaporative system problems of this sort. It works like this...

Your fuel system is composed of two different systems... the liquid portion that you're familiar with and the vapor portion that's called the evaporative system. Leakage from the evaporative system is monitored by the use of this same NVLD device, a detector that is open to the evap system and its pressures.

The detector is composed of a diaphragm, a set of contact points and a solenoid. When testing the evaporative system, the solenoid is de-energized to allow the system to be sealed. At that point, the purge solenoid is opened to allow flow which draws vapor out of the evaporative system where it's burned in the engine. The act of drawing vapor will produce a drop in pressure, something the NVLD should notice easily as it closes its internal switch contacts... notifying the PCM (engine controller) that the purge system did, indeed, perform as was hoped.

The difficulty is in monitoring the NVLD without a scan tool (tough) and verifying that the evaporative system is leak-free without the special tools required to test for leaks that will amount to less than a pinhole throughout the entire evap system... which begins at the gas cap and ends at the engine. My experience with the P0441 is that it usually does not involve a system leak... but it's still possible. I'd look for just a few things at this point and then (probably) replace the NVLD.

Slide under the left side of the truck about even with the driver's door handle and look up. Above you will be the evaporative system's storage canister (often called a carbon or vapor canister) and the NVLD. Examine the odd-shaped hose that exits the top of the canister and connects to the black plastic thing-y with 3 wires (NVLD) for cracks. The NVLD will have this one large hose and another connected to it and is forward of the canister. This hose is a common source of evaporative system codes. If nothing is found, check this...

The wiring to the NVLD itself. It's fairly exposed on the DR model trucks and can be struck by road debris or pulled on by snow/ ice acculation. Breaks within the individual wiring of this pigtail harness do happen on occasion, sometimes without the wire visibly breaking in half.

Give each of the three wires a good tug to see if they will snap, indicating an already broken conductor within the insulation. These wires are pretty strong, so you can put a pretty good effort into it without fear of breaking anything. The break may be close to the NVLD or it might be farther up the harness within the black plastic convolute sleeve it disappears into. Expect all damage to be within about 18" of the connector end... if at all.

And if nothing is found... and you're OK with a gamble... replace the NVLD. It's not a difficult replacement and the new part would likely be half what your diagnostic charge at the dealer would be... around $60 if memory serves.

Clear your PCM memory after repair by doing a 30-second battery disconnect and you'll know within a few days if the repair was successful when the Monitor has run a couple times.

If you have any questions or problems, be sure to write back. I'll be glad to help.

Good luck!

Dodgerench and other Dodge Specialists are ready to help you
Customer: replied 7 years ago.
thanks I am a land rover tech so I pretty much know what I am doing I was just not sure how to go about testing the system because I dont have any chrysler diagnostic tools or system info. I have had to replace the 2 big hoses on the canister because they were leaking. I guess I will try the nvld if everything else checks out ok. Thanks
It's a pretty high probability fix when you can verify the evap system's tight. Check your wires at the NVLD closely and then toss the thing if nothing else is found wrong.

I'm encouraged with your expertise, so we can go much deeper than normal over JA here if you have any problems or need assistance. Just holler!

Customer: replied 7 years ago.

thanks alot

Thanks Muddin! Let me know either way, OK?

Talk later,
Customer: replied 7 years ago.
ok I will