So I got the infamous Gascap warning on my dash. I went and bought a new one, and replaced it. I did the on/offx3 test and NO codes popped up. I didn't get around to resetting the code.

So I checked it today (my wife drives it) and the engine light was on. I got the following code:

P0457 EVAP Emission Sys Leak Detected (fuel cap loose/off)

What do I need to do? It's got a brand new cap. Could there be something wrong with the filler neck or something?

FYI, it's an 07 with the 4.7 v8.

 

Try disconnecting the negative terminal on the battery for a few minutes to reset the system,
FF

 

I got my code to go off and truck to pass inspection by filling around the o-ring in the gas cap with grease.

My gas cap just doesn't seem to fit tight enough anymore. I bought 4 new gas caps trying to get one that would stop the code.

 

Okay, sorry for the delay with the reply. I unhooked the battery and reset the system. It went away...

for one week.

Got home tonight and have the gascap code and now a P0456. That one is a small leak detected. Should I try another gascap? Should I try some grease on the oring? It's REALLY hot here this time of year (AZ). Could that make a difference?

Or should I break down and take it to a mechanic?

 

try the grease trick, and then see if that works. and then if it does go out and get a new gas cap

 

Okay, now I'm getting the code P0440 which is evap system perf I believe. We've also been noticing a MUCH larger amount of condensation under the durango than what we are used to. Pretty much EVERY time we drive it or move it. Could those be related?