I agree with Philip. Avoid this place. Went and was doing the check, everything normal. Five seconds before he tells me to turn off the engine, he fiddles with some knobs on his machine and my Check Engine light comes on. He tells me I failed and collects his fee. I'm a little upset so I go straight to my mechanic and show him the certificate and he laughs and tells me there is nothing wrong with my car. He gets under the hood, while I watch, and checks around and then connects his computer to the car and resets the chip and light. Then tells me to drive around for a while and then get it retested. I went to Terrible's on Lake Mead and passed with flying colors, no problems.
I don't know what the guy Jiffy did, but I don't think it's funny at all. Oh, and no free or discount retesting at Jiffy, like other places. I only went to Jiffy because they offer registration renewal on the spot. Never again. I'll just renew online and save the ten dollars.