The check engine light on my 2010 GC with 80,000 KMS 3.3L engine came on. It gave the code P0456 small evap leak code. First thing I did was remove the gas cap and reinstalled it. I don't think that fixed it since the light is still on althought it may require a little more driving to clear it.

The last time I put gas in was about two weeks ago, when I overfilled my tank by about 3 liters (dumb move on my part). Could this have caused damaged something and throw the P0456 code?

 

Update, took out the gas cap and removed some gunk with a rag and put it back in and drove it around. But the check engine light stays on, AND when I do the key dance, I don't get a P0456 code anymore. It just stays "--------" followed by a "--DONE--" msg. Does this mean no more evap leak is detected? If that's the case why is the light staying on without givinge me a code?

 

could be some gas got into a vent line where it shouldn't be. Take it to a parts store with a code scanner (they do it free here) and have them read anything, and ask to clear it. You could just have a residual light that needs reset