Not sure if I fixed it (hard to tell for sure with these codes), but I did get a lot of starts for a couple of weeks using a full tank of gas with no codes.

I was getting P0440 pretty regularly, so I did the standard free stuff - check the hoses and replaced cracked/bad looking ones, but it didn’t fix anything. I looked the potential problems for the code in my book and there are a lot of potential trouble spots, so I replaced the gas cap with a new one from the dealership. Once I replaced the cap I stopped getting the P0440 code.

On the P0441 code it looked like it would be the hoses (which I already checked) or the pump or the vapor canister. I ended up getting a new pump and vapor canister (there’s over 166,000 miles on it), and installed them and used some silicon lube and new clamps on all of the hoses and the code hasn’t returned yet.

I realize the problems probably don’t cause any real performance issues, but here in Arizona I do have to have the truck inspected every year, and if the check engine light is on for emissions you fail. You can fail once, but if you fail a second time them you can’t re-register it.

 

that's dumb about the 2 pass rule. I just clear my codes with the tank near empty, run the tank out and refill it to clear all the checkpoints (I failed 3 times last time due to non-cleared checkpoints), and get it inspected right before the light is due to turn on.

 

They used to have a deal if you could show you spend some amount of money to fix it and it's still broke they'll let you pass.

I've also heard of clearing the codes just before inspection working and not working. I guess it depends - they check the number of miles since the codes have been reset. Maybe your routine works best?

In any case, the new parts weren't really that expensive and were fairly easy to replace.

 

the PCM has checkpoints for all of the emissions systems. open loop cold, open loop hot, closed loop cold, closed loop hot, WOT under 30, WOT 30-60, ect. All checkpoints must be achieved. HOWEVER, the charcoal system only operates if the tank is less then 3/4 tank and greater than 1/4 tank.

So with good timing, clear it at 1/4 tank, run it dry and refill for max miles to hit all checkpoints, then check it right before it wants to run the system. On the 4th try, all the checkpoints had been marked.

 

I didn't know how it worked...

I guess my fixes were only being tested when the tank was 3/4 to 1/4 full?

 

I was getting a P0455 on my 2000 Dakota sport 4.7 120,000 miles. All lines seemed fine but the gas fill tube was rusted like the titanic and actually had a hole in the vent tube. I replaced it and the code is gone, but only been a little over a week. About how long does it usually take for these codes to clear?

Here's what my filler tube looked like compared to the new one I replaced it with:

 

Wow, that was really rusted out!

I have a tool to reset the codes, so I don't know how many good starts it takes to reset it. Maybe someone else does?

 

You can clear the codes and reset the PCM yourself by disconnecting the negative battery cable and holding the key in the start position for about 30 seconds. You can also stop by Advance or Auto Zone, the parts store guys can clear the code with a code reader. You can buy a cheap code reader for future use, I think Advance has one on sale this month for $50.00.

Jimmy

 

our trucks have a gift .they will read the code for u..turn key from off to on (no start) 3x and look at the display