I said I set the TPMS "at" 36 not "to" 36: that is I did the calibrate procedure when the tyre pressure was 36. No question that the car operated correctly. I didn't say otherwise. I said I was disappointed that the margin of error is 20%. The way to make this work in the way you suggest, is one that I already mentioned earlier in this thread. It is a work around, and I may try it next time, but fairly time consuming and not guaranteed to make one popular with the other drivers who are waiting to use the air line at the petrol station! But I disagree with you as follows: 1. I very much doubt that the reason for having to calibrate the TPMS is in order to set your own warning levels in the way that you suggest. Surely it would be FAR better if that were the aim, to allow the customer to set their own warning alert thresholds on the TPMS screen. That is, to alert when pressure goes below a specific user specified PSI value. 2. The sensors generally have a margin of error of +- 3psi don't they? So not entirely true to say that the car knows the pressures to one tenth of a psi. 3. My reading suggests that the TPMS does not alert for pressures that are too high, as I said, and it sounds to me like @bwilson4web can confirm this from his own experience. Can you provide documentation to back up your view? Posted via the PriusChat mobile app.