Ultrasonic range finder detecting 0mm all the time

Hi, I have a class set of 6 VEX V5 kits, basic build with 2 motor drivetrain and a few line trackers attached. We have also attached a Ultrasonic range finder to it, but it always registers that an object is 0mm in front if it. We are using the Ultrasonic sensor example script from VEX CODE pro. Ive tried switching the input/output ports. We’ve tried ports E&F, and G&H, but no matter what we do on all the kits with any of the ultrasonic range finders it still displays 0mm on the brain screen. Can someone please assist with this.