Thanks,

Gives me a little more to look into, or at least focus on. Surprises me one of these could be bad after only 40k miles. My dodge truck has 140K and the evap system has been fine.

Don't emission systems have a longer warranty than the 36k/3yr?

 

Today the display showed gas cap. I am going to replace that first but could a bad gas cap cause the p0440 code?

 

A loose gas cap will set: P0457-LOOSE FUEL CAP, and GAS CAP will be displayed in odometer

I don't know if it will also set your P0440 code. I would bet not, since a loose cap has it's own code.

 

Seems odd I would get a leak somewhere in the system and have a bad gas cap within a weeks time. I am picking up a cap on the way home so we will see what happens.

 

i have the same thing going on. a day or so after the gascap display i throw a p0440. already been to dealer once. did not fix. my evap canister had some minor damage. so i siliconed every where it was nicked just to see if that was the problem. a few days later got the gascap on the display and then the next day p0440..


i think the leak is somewhere other than the gascap. in my case this all started after some minor damage to the evap canister. so i bought one. i still need to install it.


the funny thing is is when i was under the other day checking
for split lines i wiggled everything and twisted what would twist and i haven't had the check engine light come on again.

 

Just thought I would post for anyone who might dig this up in the future. I replaced the gas cap the other day with a new one I picked up at the dealer. So far the errors are gone and haven't come back. Its only been a couple days but so far so good. I will update again after a few more. Seems, so far, the p0440 code can be caused by a bad gas cap.

 

Still having issues with the evap system. I replaced the gas cap and new codes came back a few days later. The new codes were p0456 p0457, and GAS CAP! I replaced the Leak Detector pump and now get the codes p0456 and p0457 but do not get the gascap even though the p0457 code is loose gas cap. I am thinking that I should try replacing the purge solenoid next.

Ronjenx mentioned EVAP PURGE HOSE/TUBE AND FRESH AIR FILTER OBSTRUCTION in his post. Is this something that I need to replace, or could I some how check this fresh air filter and clean it?

 

I had this same thing just happen....got a random gas cap alert. I didn't even remember to tighten it because the nest time I started the Jeep it wasn't on. Now, P0440...great. First thing on start up after sitting all night. I think I am going to clear it and hop for the best. EVAP is not a mission critial componant so F it.

 

I just checked the dealer and the leak detection pump is only $9.95, I just about fell over when he told me how cheap it was. I spent hours trying to fix mine after I broke it when I was doing the Evap relocation, I thought I fixed it good but I keep getting a code every couple of weeks saying I have a small evap leak and I am guessing this must be it since I broke it almost in half and glued it back together.

 

Got a part#...sounds reasonable enough to give it a try.