Evening everyone.

I was on a 240 mile round trip to see family yeaterday and today. I was merrily bombing down the M40 at 70mph when I heard a "Boing", looked at the instrument panel and saw the dreaded red triangle. The message said "Tire Low". Why they couldn't spell it in English and not American is beyond me. Anyway, stopped at the nest exit, checked the preasures on all four tyres and they were all at 33psi. Got on my hands and knees and pressed the tyre reset button and all was well. My journey back, half way again and the warning comes on. Did exactly the same as before and no more warning. It is going in for a service in July at Lexus Woodford and I was wondering how the sensore worked, where are the sensors, and also should I tell Lexus about the problem as the sensors might need replacing under warrenty?

Many thanks again everyone.

Why on earth would you NOT tell Lexus?
Obviously there is a fault on the sensor if the tyres are reading the same PSi

The sensors work by sensing a sudden change in pressure. Did you hit a pothole or bump before the warning came on?

The ones on my BMW monitored the pressure and temperature, the idea was when you have pumped your Tyre to the correct pressure, you press the set pressure button, then if the pressure falls by a certain amount you would get a low pressure warning, if the Tyre pressure dropped rapidly you would get a blow out warning, the temperature sensor is to compensate for temp v's pressure.

one thing to note is that you cannot use puncture repair spray, it will stop your sensors from working

Also they are usually located where the trye valve is, and they work by radio transmission, Now that you mention it, mine used to give me a warning when I passed the RAC building in Bristol on the M5, I assumed it was because of the powerful radio transmitters they have interfering with the signals, did the fault happen in the same area of the M40?