Leonardo

On 16/2/2023 at 05:26, GS450hSE said:

2008 GS450h (RHD UK version) 45,000 miles

With no prior warning or reason, after 10 miles driving alone* @ motorway speeds, a TPMS "Check System" error flashed up. I checked tyre pressures - all fine, given they were warm.

I've not encountered this before. Of course I've had Low Tyre Pressure warnings, which usually meant that one of the tyres needed to be topped up, but occasionally/rarely were false warnings that went away by themselves.

This "Check System" error stayed on during the rest of the 70 mile drive. Now safe in a World's Hardest Game driveway, I went through the procedure in the instruction book - Power On, pressed/held down the "SET" button (which they describe as the TPMS warning reset button) located beneath the steering wheel, but no "PRESSURE INITIAL" error message appeared - the "Check System" error remained displayed throughout. Tried the steps a few times, without success.

I checked if, by some miracle, the Main/2nd TPMS button under the glove box was on "2nd" (since there was no passenger, how could it - nothing could have touched it) - nope, it was on "Main". I tried Main -> 2nd - Main but this too didn't displace the "Check System" error.
Nor was my Bluedriver Android app (which is paired with the Bluedriver gizmo plugged into the GS450h's OBD-II port) able to give more information or clear the message.

Am I missing another fix, or does it sound to you as if one of the sensors (all the same age) has a low battery? If so, and the sensors are sealed, it would be sensible to put a brand new set of four in the car. The sensors are at least 6 years old and probably quite a bit more.  Or can just the battery be changed?

And - if it isn't a battery - what's the next most likely cause, please?

I also think it's very likely that the Battery is the problem. I also had some similar problems while traveling in the south america.