I just install all 4 wheels with new sensors, left front sensor battery was 1.5 volts after removing the old sensor should be 3v. It is a liitle work installing the tpms number 25758220 That is the GM part number OEM price for 1 is well over $100 I purchased mine at Amazon $32.99 all 4 and are the same. I was quoted from Firestone $110 per tire. The biggest amout of work is to bust the bead on the tire I used aneminry manuel bead buster and a inpact wrench for that job. You will need some wood of the like to keep the bead open while removing and installing. (warning do not drop the tpms into the tire that happen on one) I had to take it to my loacal shop to remove the tire from the rim, Big thanks to the guys at Firestone! Being to tired to complete the reprogram will be doing that today, using another tool from Amazon EL-50448 using your fob depress the lock and unlock buttons till the horn beeps twice then just go rf,rl, bl,br holding the tool to the side wall of the tire till the horn beep once at each locations. I set my tires at 30 psi (cold)