Yes it will work for 01 tahoes. I bought this new for 325.00. The programmer will allow you to install a preloaded tune. Or allow the user to change most of the engine settings. You will also be able to adjust the computer for larger tires. This will get your trucks, speedo and shift points back to where they need to be. It will also do away with the 99 mph speed limiter the factory had on it. I could tell that the truck had more power with the programmer on it.01 tahoes?