hello. I have a 2008 Pontiac g6. my tire light came on from a dead sensor. my local mechanic replaced the sensor with a new one and re-programmed all four tires successfully(each tire chirped with the scanner then the two chirps when the key was turned off) the light was still on so he hooked up his computer and said he did a factory reset or whatever on the tpms. he then said for me to drive for 30 miles above 25mph to complete the reset. so far i have driven 45 miles with an average speed of 35. why is my light still on. do the tires need to be re-programmed again? thanks for your help.