Using my Autel TS401 to read all the TPMS sensors and my Autel MaxiDAS to verify the sensor/wheel locations, I have determined that on the E70, the system will automatically relearn the TPMS sensor locations correctly if the tire/wheel position is changed when you press the TPMS button to actually start the relearning process. You will have to drive the car about 300+ feet for this relearn to occur. Unclear if you replace a sensor if the system will automatically update the sensor ID as well? I have not had the need to do this yet.

I am not sure what happens if you install a TPMS sensor in the spare tire how the system will react, but for those of us that actually have a spare tire option, buying a Autel sensor, programming it and installing it in the spare tire location this may be an option. I recall seeing 5 positions listed on my Autel and SnapOn tools. It would also even make checking of the spare tire pressure with a tool like the TS401 very quick and easy. This assumes the Autel sensors can easily fit the steel wheels.

The TS401 is a very good deal at under $80 if you can get one at this price. Pricefalls listed around 250 units available at that price?? I was fortune enough to get mine at my front door for $78.63.

With the ability to quickly check tire pressures without taking valve stem caps off, ability to read the TPMS sensor ID and battery condition, ability to troubleshoot TPMS sensors and the ability to actually test keyfobs I think under $80 is a steal of a deal.

If anyone finds a decent, lower cost add on TPMS receiver and/or a complete system, it would be interesting to see how much an add on would cost. I recall Bosch or someone had a system I heard about, but I have not researched this.