zanda, don't cut it dude, i had to cut my old sensor because for f**ksticks who did my cat for compliance welded the bloody thing on. i managed to get hold of a new sensor easily enough though. when i cut it, the cat light came on, on the dash, and stayed on all the time. it's there to tell you your cat could be blocked, but because mine was cut, that's what it was thinking. if i left the car idling for about 2 minutes it would turn itself off with this sensor cut (as greygirl1976 said, limp mode). you could just unplug it from under the seat (i don't know if this will cause the light to come on or not), or just tie it on to the cat, or just plug it in. mine is currently plugged into the car, but not connected to the "cat", just tied onto the side of it for now and its fine.