If you're looking to disable the tracking on your car, there are a few things you'll need to do. First, you'll need to find the tracking device itself. This is usually located somewhere on the undercarriage of the vehicle. Once you've found it, you'll need to disconnect it from its power source. This may be a battery, or it could be hardwired into the car's electrical system. If it's hardwired, you'll likely need to cut some wires in order to completely disconnect it.
Once the tracker is disconnected, you should then remove it from the car entirely. This will ensure that it can't be reconnected and activated without your knowledge. Finally, you should consider taking steps to mask or scramble the signal emitted by the tracker, so that even if someone does manage to reactivate it, they won't be able to track your car's location. There are a number of ways to do this, such as using a GPS jammer or blocker.
With these steps taken care of, your car will no longer be susceptible to tracking devices