If your OE TPMS valve is broken and you're looking for a replacement valve, the first thing you'll need to do is determine if your vehicle uses a Siemens sensor or a Continental sensor. 

If your vehicle is using a Siemens sensor, you won't be able to replace the valve stem. A new sensor would have to be purchased. 

If your vehicle is using a Continental sensor, you can replace the valve with the CONTIVALVE. You can purchase the CONTIVALVE here.