Had a little disaster myself the other night with tyre pressures. The warning light came on and as I was about to drive 50 miles down the motorway thought I would stop and check them at a garage, normally use my own compressor. Topped the front tyre up to 38 but tool was was a bit stiff on the valve to come off, when it did it took the end of the valve off with it. Result totally flat tyre, no spare and needed recovery. Left the car at home till next day and phoned around local tyre firms but none of them can fit the sensors. Called lexus care to see what they could do, AA arrived and after a few phone calls a sensor was ordered from the dealer (bolton). Tyre was fitted with a normal valve for now but a trip to the dealer is imminent when the part comes in. I can see these sensors causing a few problems until more tyre specialists can obtain and fit them. Looking for a space saver now. I did find the reset switch though after looking for advise on here.