Same situation happened to me. The guy running the station was professional, plugged it in my Mercedes told me it was "rejected". I asked why. He asked if I had the car served - I told him I did get new tires and a battery. He said the car can't be tested if the battery was replaced and the car as to be driven 100 miles after service or else it will automatically fail since the computer is not charged (???). Well why didn't you ask that before or have a sign pasted that says if your car was recently serviced not to have it tested for a minimum of 100 miles. I would have waited had I known or been told. Paid $10 for nothing - what a scam, I will not use another Jiffy Smog location ever again.