I am having the "Check Gas Cap" message almost everytime I am stopped at a traffic light. I took it in to get it fixed but the amount the dealer wanted to charge to fix was outrageous. The dealer did a smoke test and found it was the charcoal canister leaking. I was wondering if anybody has a photo or diagram of where this is? I was told somewhere in rear of vehicle. I am hoping to buy the part for $150 and change it myself. Thanks