Dodge Gurus - Help! P0440 Code

[tony1679]

This is a new to me 2003 Dodge Dakota 4.7L 2WD SLT Quad Cab.

I have looked through so much information and been through so many forums I can't see straight. I keep throwing codes P0440 and P0441 (more often the P0440). I have read all of the tips and tricks. Here is what I have done so far:

-Replaced gas cap
-Cleaned and checked vacuum lines between canister and leak detection pump
-Checked vacuum lines from purge solenoid

*Still no fix

There is also one other problem, and I'm wondering if these are connected. I also have a rough idle and a slight hesitation only when gas pedal is first pressed. No related codes, no apparent misfire. When the throttle is applied (regardless of how much) it runs perfectly. Problems only at idle. Here is what I have done to address that:

-Checked air filter and flow to throttle body
-Again, cleaned throttle body
-Replaced spark plugs (NGK 6987s - proper plugs found after hours of research)
-Replaced throttle position sensor
-Replaced idle air control valve
-Replaced positive crankcase ventilation (pcv) valve
-Replaced fan clutch (thought maybe it was stuck and reducing power, needed anyway)

*After all of this there is a very slight improvement, but not much

As for the codes, they will NEVER come on at random, they will only pop when the vehicle is first started. When a code pops, I have it scanned to confirm the same code, replace the next suspect part, then have it cleared and wait for it to repeat. What would be the next suspect part in the evap system? I am thinking either the leak detection pump or purge solenoid. Any help or guidance would be greatly appreciated!

 

[OneEyeJack]

Have you tried this?

 

[AandPDan]

A couple of things. You don't need a scanner to get the Codes, do it yourself. Beginning with the truck OFF, turn the key to RUN (don't start it) then OFF, back to RUN, then OFF, and this time leave it in RUN. Any codes will display in the odometer window. It'll show P DONE when finished.

Not related, but the "proper plugs" are Champion RC12MCC4. That's what it came with. Copper plugs conduct better - but I can already hear the growling over this.

For the rough idle, take the throttle body off and clean it, thoroughly. Remove the IAC, be careful with it, and make sure the passages are clean. You'll be amazed at how much carbon is in there.

P0440 - General Evap System Failure.

You started with the gas cap, good. Did you check the filler neck? There can be corrosion on the neck itself causing a leak. Does the code seem to happen more often when you reach a certain fuel level?

You've checked ALL the hoses?

Make sure the Evap Purge solenoid vacuum supply hose isn't pinched or blocked. Can you feel strong vacuum?

Do you have a hand operated vacuum pump? Connect it to the Evap Purge Solenoid canister side, apply 10"hg of vacuum and monitor for 15 seconds. It should hold.

Most of the rest of the tests require special tools. Basically you use the DRB to monitor the NVLD status and smoke test the system.

 

[Yazmeister]

Replace hoses to and from the evap canister. Had the same problem with my Dodge Ram 1500; the canister degraded and clogged the hose to evap purge solenoid.

 

[tony1679]

Originally Posted By: tony1679
-Replaced gas cap
-Cleaned and checked vacuum lines between canister and leak detection pump


Yes. I physically removed all of them, washed the dirt off, and filled them with water to check for leaks. They were fine.

 

[tony1679]

Originally Posted By: AandPDan
Not related, but the "proper plugs" are Champion RC12MCC4. That's what it came with. Copper plugs conduct better - but I can already hear the growling over this.

Agreed. The NGK plugs that I installed are the proper "brand alternative" that are also copper and the proper heat range.

Originally Posted By: AandPDan
For the rough idle, take the throttle body off and clean it, thoroughly. Remove the IAC, be careful with it, and make sure the passages are clean. You'll be amazed at how much carbon is in there.

I have...

Originally Posted By: tony1679
-Checked air filter and flow to throttle body
-Again, cleaned throttle body
-Replaced spark plugs (NGK 6987s - proper plugs found after hours of research)
-Replaced throttle position sensor
-Replaced idle air control valve
-Replaced positive crankcase ventilation (pcv) valve
-Replaced fan clutch (thought maybe it was stuck and reducing power, needed anyway)

Originally Posted By: AandPDan
Did you check the filler neck? There can be corrosion on the neck itself causing a leak. Does the code seem to happen more often when you reach a certain fuel level

Not specifically, but I can't smell any fuel (I checked carefully). Plus if it were corroded wouldn't it leak when I fill it?

There is no pattern to the code and when or how I fill.

Originally Posted By: AandPDan
You've checked ALL the hoses?
Yes, unless there are some I can't see. Hoses to and from the purge solenoid are fine, as well as to and from the canister/ldp.

 

[tony1679]

Any other ideas?

I think I will try the leak detection pump next. I am really tired of throwing parts at it. But I am even more tired of seeing the CEL...

 

[AandPDan]

I can understand why you want to do this yourself but if you don't have the tools to smoke the system or run the diagnostics with a DRB or equivalent, it's best to spend the money at a shop. You can spend a lot of money tossing parts at this.

 

[tony1679]

Agreed. Here's my theory:

The CEL will not appear randomly. It will only appear when I first start the truck. Which means it has performed a vacuum test and it has failed (or not responded indicating failure). Due to this failure/response I think it is something electronic not working. The only two things left are the purge solenoid and the leak detection pump. But if the CEL indicates an evap LEAK (failed vacuum test/no response), I think the leak detection pump would be the cause...

That wasn't really a question, more like thinking out loud, but off to get a leak detection pump either way. If that doesn't work, then I'll try the purge solenoid.

I guess if both fail to fix my problem, then off to a shop I go (with a lot of variables eliminated). Thanks Dan.

Either way I'm still entertaining any and all thoughts...

 

[Kuato]

An 11-year-old vacuum hose could hold water under pressure, but then leak air under vacuum. You may also want to check the attachment points for the hoses, I once found one that was cracked and leaking.

 

[oldhp]

I had a 2003 Dakota 3.9 V6, was showing evap control code. The dealer's have a kit to replace the problem hoses that basically crumble. Bought kit and replaced all the hoses, ran a clock, no more codes.

 

[tony1679]

I hate digging up somewhat old threads, but felt it was important to post results to possibly help anyone who may have similar issues. The solution to my CEL problem was in fact the leak detection pump. No CEL after 1 1/2 months and ~3,500 miles. Thanks to everyone who tried to help!