My estate vRS suggests 2.1 bar front and 2.2 rear on part load (normal load in other words), equates to about 30 front and 32 rear in PSi.

After running the factory figures for a while have found the fronts wearing prematurely and they also look a but underinflated. Now running 2.2 bar (32 psi) all round and much better, see to be wearing a little less quickly too.

Yes I would guess that is probably how the measurement is taken, some kind of magnetic contact made on every rotation perhaps.

Yes, there is a toothed hub which means the ABS sensor is constantly getting pulses as each tooth passes the sensor and therefore allows the car to work out the rotation speed of each wheel.  One failed on my car recently with corrosion which my mechanic was showing to me, quite interesting as I'd never thought about it before. 

 

To the OP - are you trying to reset the light when the car is still or in motion?  I'd have thought if it was a sensor fail you'd have the ABS and TCS lights on as well since it's the ABS sensor the system uses.

 

John

To the OP - are you trying to reset the light when the car is still or in motion? I'd have thought if it was a sensor fail you'd have the ABS and TCS lights on as well since it's the ABS sensor the system uses.

I've tried just with the ignition lights on, with engine running and in motion but it always remains on???

Try it with ignition on but engine off, hold set in the dash for perhaos 3 or 4 secs, you should get a bong and the TPM light should go out.

Some newer vag cars you don't get a bong confirmation.

The sharan shows the symbol on the dash if resetting due to topping up, and flashes and extinguishes if resetting following a tpm warning.

Some newer vag cars you don't get a bong confirmation.

The sharan shows the symbol on the dash if resetting due to topping up, and flashes and extinguishes if resetting following a tpm warning.

 

My vrs was made in 2012 and it bongs when you hold it in. It might be something that VAG are phasing in. It might not bong in the mk3 octy

Try it with ignition on but engine off, hold set in the dash for perhaos 3 or 4 secs, you should get a bong and the TPM light should go out.

Tried that but no joy. I checked all the tyres today. They had all lost 1-2psi but that could've just been with the cold weather? Tyre pressure light still stays on ????????

The only thing I've noticed is both front tyres are down to 2mm. Could this effect it or is it more likely to be a sensor???

Tried that but no joy. I checked all the tyres today. They had all lost 1-2psi but that could've just been with the cold weather? Tyre pressure light still stays on ????????

The only thing I've noticed is both front tyres are down to 2mm. Could this effect it or is it more likely to be a sensor???

 

If rear tyres are newish 8mm and fronts are 2mm or less this can make 38mm approx difference to the circumferance of the tyres. Not sure what the threshold is that triggers the warning but i guess this could be a factor.

 

That said However the light should still go off when you hold the button in for the prescribed period.  It should then detect the discrepancy after a few hundred yards and bring the light back on. But if your light is not turning off while the car is stationary then you have a problem with the system.

That's what I was thinking. Many thanks.