Tech 2 clones are available from Asia for ~$300 and you can do everything the dealer could on your Avalanche with a Tech 2. You can reprogram modules, do true 2-way functions to verify operability of components. For example, I can roll my windows up/down with my Tech 2, I can put things into test and diagnostics mode, read ALL sensor data on every system. I can control audio, HVAC, rear wheel steering, lights, and more. For $300 I highly recommend it for anybody with an OBD 2 GM vehicle prior to 2010-2014 (the comms protocol was switched over in that range, the exact year depends on what vehicle you have).