Interesting TPMS data after rotating tires



Did the first tire rotation on my car yesterday (yes, I know BMW recommends against it) and saw something that surprised me when I went to the TPMS screen.

I have a square setup, so I did a traditional "fronts cross to the backs, backs slide forward" rotation. After that, I needed to reset all the tire pressure setpoints to accommodate the back tires being 4 psi higher than the front. When I pulled up the TPMS screen, it was showing the back tire pressures on the front, and the front tire pressures on the back. Clearly, the car had previously identified each sensor individually (serial #? RFID?) along with its prior location, and was polling them and reporting the pressures where it thought they were.

After I did the TPMS reset (needlessly complicated in the new car - start parked with engine running, wait for a bit, and then drive) and drove about 1.5 miles while the car ran through it's "resetting" count-up, it relocated all the pressures to the correct wheels on the display.

This seems a bit bizarre. The car can apparently determine which sensor is on which hub, but doesn't in normal operation, and instead uses an ID number to place the pressures around the car. I honestly can't think of a design reason to do so.