Roughly three weeks ago my SES light came on for the first time; I have roughly 24000 miles now. That day it was the hottest it has been, and so when I got in my X around 1pm to drive off, I noticed the SES light was on. I stopped by my dealer, and the first thing they asked me was if I purchased gas recently, and to check my gas cap is on securly. I took off the gas cap and got a huge burst of gas vapor; figuring now the SES light came on because the hot weather was causing the gas vapor to expand and put force on the gas cap. I put the cap back on and within ten minutes of driving the SES light was now off. Now today I had a similar issue; around 3pm the same scenario begins to play out. Only now after removing and reinstalling the gas cap, the SES light has not gone off.

No advice for you but I am having the same problem with my '06 Frontier. Tried putting on a brand-new gas cap, light still on. Just ordered a code reader to find out what's going on before I go to the dealership. Gotta love a warranty.

We got 109 degrees here and I have no light on for my truck. This is the second summer for the truck too.

I'd bet it is a malfunctioning Solenoid for the emissions system or the canister is bad.

Post up the Code and or the fix if it is determined.

Go to Auto Zone and get your vehicle's computer scanned for free. They will tell you which trouble codes are stored in the computer's memory. This will help in diagnosing your problem.

Update.....I went to Autozone today and they read my computer to do a code check for the SES light. The code reader produced code: P0455; a large emissions related vacuum leak. It listed 5 possible reasons for the code: gas cap, e-vap canister, vacuum lines, etc. Can anyone provide me with advice before I see the dealership? I've already ordered the Stant Locking Gas Cap from CourtesyParts.com