Can I take my own Easy Pass and use it in a rental car?

Technically yes, however, you must make sure that it is properly adhered to the windshield in order to be read. If the sensors are unable to read it they will take a picture of the license plate and the rental company will charge you for the toll and likely a fee or penalty as well. If the rental car has its own Easy Pass you’ll also need to be sure it is removed from the windshield and properly stowed so that it cannot also be read.