In-car tyre pressure indication

[fixitflav]

Anybody know how these things work? Seems very clever?
Just had my low tyre pressure warning light light come on. Blew them up but the light stayed on. I groaned and thought it was going to be code reader issue, but after a short drive it reset. Inflated to 32 psi front, 33 psi rear, and the dash said just that. I expected it to be there or thereabouts, but quite impressed that it agreed spot-on with the airline.

 

[Burnerman]

Brilliant devices, I agree!
Expect them to show up a fault when there is around 3 to 4 psi difference on the axle.
They transmit to a module within the car. Some will tell you which wheel has the fault, others just a general alert.
Some reset automatically, some have a ‘set’ button on the dash, others have a more complex reset system.
The direct types have a battery within the valve with around a 6 year life, other indirect types use the ABS system as a soft tyre has less of a rolling radius. It’s probably best to replace the sensor if it’s getting on a bit, just in case the tyre lasts longer than the sensor itself.
John

 

[Munroast]

Anybody know how these things work? Seems very clever?
Just had my low tyre pressure warning light light come on. Blew them up but the light stayed on. I groaned and thought it was going to be code reader issue, but after a short drive it reset. Inflated to 32 psi front, 33 psi rear, and the dash said just that. I expected it to be there or thereabouts, but quite impressed that it agreed spot-on with the airline.

sounds like yours work from the abs sensor, so it would not have known you had blown the tyre up until you drove a little way and it could work out the tyres were back to the same diameter.

Some cars have a reset button, so if you fit a tyre of a slightly different dia, you can tell the car this is OK.

 

[fixitflav]

Thanks gents for the comments