This may not be news to some, but after many months of problems with the tyre pressure monitor on my 2018 Jazz, I have at last found a solution. Well, one of two possibilities actually.
When I had a tyre changed about 6 months ago the tyre pressure monitor started pinging. No matter how much I reset the monitor and checked the tyre pressures, it kept pinging. A Honda dealership recommended fitting two (more) identical tyres (costing about £150), which I did. But it kept pinging. Another Honda dealership then told me there was "nothing" that could be done. However, it occurred to me that the auto-stop had also not been working for the last few months. I had assumed this was due to the cold weather during winter, but now the weather was warming up and it was still not working.
So I then did yet another Google search and found two ways to reset the electronics, as reported by others. One was to pull the bonnet lever while the engine was still running. Then switch off the engine, and open and close the bonnet. The other was to disconnect the battery from the black box next to it. I found that there is a lever-controlled multiway electrical connection on the negative side of the battery, so I disconnected this for a minute or so, and then reconnected it. As it is hard to know whether what you read is really correct, I did both!
To my amazement new messages started to appear on the dashboard, such as "fasten seatbelt" - I had not spotted these before. And the auto-stop now works (and there is a message saying so, which again I had not seen before), and so far (after an hour of motorway driving) I have had no more pinging from the tyre pressure monitor (which I gather uses an indirect method, actually comparing wheel rotation rates.) I can only assume that I had somehow managed to reset the microprocessor and it had updated itself in the process!
I thought others might find this information useful.