heare we go c6 2007 auto , to be honest its the first time yesterday ive took it for a run over 12 miles away . yellow warning flat tyre light comes on . goes to the instruments its showing xx on all four tyres ! question is . if 1 tpms goes bad does it knock out the rest ? also i changed the cars battery about a month ago for a brand new one , do the tpms monitors have to be re calibrated one by one if the battery has been taken off . i know the tyres were also changed at some point early before i purchased it . i am in the newcastle area and had the name of a garage that specialised in vettes but lost the chaps number i think he was called john . thanks everybody and best wishes for xmas and new year , live long and prosper as spock would say ;-)