I bought the official EL-50448 TPMS tool from the supplier to GM back in 2008 when I bought my CTS but now you can pick up a Chinese clone of one on Amazon for around $14 which is probably a fifth or less of what I paid. And I am sure mine also originated in China but at that time the only choice was the official GM supplier.
If you rotate your own tires it is worth having HOWEVER most of the newer cars don't need a relearn tool (i.e. my 2016 Corvette and 2018 GMC Denali automatically learn without prompting from a tool) so depending upon how long you plan to keep your ATS it may not be worth fooling with.
The signal from the TPMS sensors is pretty weak so you can't do the relearn if there is something else on the same frequency nearby. Once I installed a new garage door opener I have to drive my ATS down the driveway after switching between summer and winter all season tires because the garage door opener interprets the TPMS tool as an attempt to communicate with it and its challenge reply is considerably stronger than the TPMS sensors which "de-senses" the TPMS receiver in the ATS and prevents pairing.
If you rotate your own tires it is worth having HOWEVER most of the newer cars don't need a relearn tool (i.e. my 2016 Corvette and 2018 GMC Denali automatically learn without prompting from a tool) so depending upon how long you plan to keep your ATS it may not be worth fooling with.
The signal from the TPMS sensors is pretty weak so you can't do the relearn if there is something else on the same frequency nearby. Once I installed a new garage door opener I have to drive my ATS down the driveway after switching between summer and winter all season tires because the garage door opener interprets the TPMS tool as an attempt to communicate with it and its challenge reply is considerably stronger than the TPMS sensors which "de-senses" the TPMS receiver in the ATS and prevents pairing.
