One went bad on the rear tire of my Yukon. I called STS, they wanted $79 for the sensor, $19 to get the truck to program the new sensor and then a fee to balance the tire.
I ordered a new one online ($27 with shipping OEM Delco), and will bring it probably to Costco to install. I read that the batteries are only good for 10 years. Now I'm thinking I should have ordered all four and got it over with. My wife is saying no more money into the truck, time to buy a new one. The owners manual explains how to reprogram new sensors.
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Don't believe everything you read on the internet- George Washington.