Can fueling with motor running cause CEL to come on?
 

I am having the most annoying reoccurring problem of my check engine light coming on and throwing the P0441 code. I do not have any leaks and I've been through a few new gas caps, but every time I get the light to go off it comes back on a couple weeks later. I'm trying to find the reason for this. Somebody told me if you gas up with the motor running it can cause this. Is this true?

yes it is 100% true

The reason is, because you vehicles computer is constantly monitoring the systems, including emissions, your gas cap falls under that, if a system test is run (you wont know when) the computer will detect a loss of pressure in the tank and will send a "gross evap leak detected" message to the computer and the light will pop on.

X2 on that

Agree with aries. I have the same code on because I have a rusty fuel filler neck

fueling with the engine running?
 

Fueling with the engine running? That’s a very dangerous thing to do I thought only woman did such a crazy thing.:icon_stooge: :icon_stooge:

Thats like jumping out of a moving car looks good in the movies but dont try it you will regret it.

But if that is why my light is on, why is it throwing the P0441 code? I was told that code is for a small leak. The gas cap off would be a big leak, no?

Also, are there actually any documented cases of fires occurring at the pump caused by a running engine? Or is that just an urban myth?

I have the P0441 code thrown on my Ram right now. The printout I got from Autozone after they looked up the code lists "defective or loose fuel cap" as one of the possible causes. If the gas nozzle has the shroud around it to collect vapors, I would think the net vacuum loss could be low enough to throw P0441. But I'm certainly no expert - just a guess.

What's the gain of running the engine while filling up? Running engine means lots of electrical charges and heat (not to mention actual combustion) happening - none of these are good to have around exposed fuel vapors. Why would you take that risk? Is it that hard to turn the key again?

I once saw a soccer mom chew some guy out at a gas station while he left his truck on and was getting gas. Quite a site and I'm not sorry to say that you are an idiot if you leave your truck on while filling up.

Don't do it. And yes it will definately cause you CEL to come on.

Just dont, dont fill up when running at all. Unless you got a diesel. Dont believe me? Get a shot glass of unleaded and diesel. Find something that creates spark, unleaded will go up in flames while a blowtorch cant ignite diesel.