Bought a 2009 4x4 over the weekend knowing about a couple of problems. First, I got the Tighten Gas Cap DIC message. Loosened it and tightened it back up, no more message. Got it again today and the check engine light is on. Was close to the local Chevy dealer so picked up a new gas cap, but the check engine light is still on. Does it take awhile to go off? Second problem. By looking at the valve stems on the tires, can you tell if the TPMS Sensors are present? I ask that cause on my vette and Camaro, the stems are metal. The ones on the truck are not, they are rubber and flexible. I ask this because the Service TPMS DIC message is present and the lighted icon on the gauge blinks for a bit and stays on. The tires are Kuhmo, not goodyears, so my first thought is that they didn't put the sensors back in when they were changed, or they didn't program them back to the truck. My vette has the DIC, and I am able to go through a lot of info with the car, are the Silverado's the same? My truck does not have the DIC menu buttons, I have to use the trip reset stem. Any help is GREATLY APPRECIATED!!!