SOT Car warning light woes.

Tyre pressure warning lights come on in cold weather for no reason as I expect you know, they are a right PITA to get to turn off even after tyre inflation and a couple of journeys (Suzuki Vitara).

My Honda Jazz deflation warning light comes on regularly about once a year. The only way to reset it is to get several levels down into the menu and initialise the warning. I assume that it's a faulty sensor, although it was correct once when the pressure was down to around 18psi due to dodgy alloys.

Very unlikely. Dodgy sensor(s) IMHO.

Have you done an internet search to see if this is known in the make/model of car you have?

Does the car cave actual pressure transducers that transmit from inside the tyre to the car, or does it make an intelligent "guess" based on the rotation speed of the ABS tone rings?

I've had several cars where the tyre pressure light came on without reason. With several attempts to reset it not working I now ignore the warning and let the workshop sort it out when it goes in for service. (I think it was once suggested that bouncing over speed bumps could cause it; there are several near my house.)

Mine come on either when the weather is very cold, or when I'm on a long motorway drive and presumably the tyres get hot. I just ignore it, it's one of many things that are more of a bloody nuisance than a feature. Not least of which is the car's tendency to jam the brakes on unexpectedly, causing the vehicle behind me to crash into my boot.

Some 60 years ago. there were some cars with electronic ignition coming to a stop on the M1 close to Daventry. According to an AA patrolman, this was the BBC's fault.

Prescient! :-).

Today, it would be because of either climate change or Brexit, depending on which one appeared more superficially plausible.

which cars were fitted with electronic ignition 60 years ago ?

At least one race tuned nova/corsa or what ever it was called at the time

Lumignition I believe was the name - apparently went like hot $&!T of a hot greased shovel north of a ton! - I knew the head engineer in that team at the time (vauxhall race team in Luton)

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Actually , when I thing about it mid 70s, there were quite a few DIY kits. I remember fitting on to my Cortina, Of course it failed - but not due to RFI,

I recall Lumenition.. Not 60 years ago. More like 54

There really were no transistors that would do the voltage and speed much before the 70s

In the place I worked, almost everyone who owned a car was building their own electronic ignition - a Wireless World design IIRC. It had the advantage that, if anything did go wrong, you could swap over a few leads and revert to the conventional ignition system in a few seconds. That was a mere 56 years ago, but that's close enough.

If it has the actual pressure sensors, they have batteries too, but you'd hope they last longer than 3 years? Blackcircles say average is 7 years.

My pressure sensors are inside the tyre (attached to the valve) and transmit. Very occasionally in very cold weather the car will report that it has lost contact with the sensor. The warning goes away after a short journey presumably because the inside of the the has warmed up. The sensors have a lithium coin cell which will fail after 5 to 10 years. The cells are potted in gunge but there are Youtube videos showing how to replace then but I guess most sensors with failed batteries are just replaced. For my car third party replacements are around £10 each (including valve). The genuine parts are around £40 each.