A few months ago, the TPMS light illuminated on the dash of my Toyota Prius. I looked at the tires and they looked fine, so I went to each tire measuring the pressure and they all appeared to be fine. I assumed that the battery in one of the tire sensors had died, but how can I tell for certain?
I found a project on hackster.io titled, “Arduino TPMS Tyre Pressure Display” that led me down a rabbit hole learning about TPMS. I found that there are two different types, indirect and direct. The type in my Prius are direct type, which measure the actually pressure in the tires. I also found that in addition to the tire pressure, they also report the temperature and battery health of the module.
All this information is available, but Toyota does not show this information anywhere in the 2007 Prius. If they did, it would improve safety and better experience in the following situations.
- Stop running around the car to determine which tire is causing the dash light to illuminate.
- When on a road trip, know if you need to pull over immediately or if it can wait until you arrive at your destination.
- Identify slow leaks so they can be taken care of right away.
- Improve gas milage by allowing the driver to top off the air pressure if it is a bit low, but not low enough to trigger the TPMS dash light to illuminate.
This project aims to help address the issues above and make up for Toyota not including this information on the information panel. The code and information are available in my GitHub repo at https://github.com/richteel/tpms/tree/main.
