Tyre pressure issues

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Woodhouse
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Post by Woodhouse »

Anyone able to help? 2023 with 9K on clock. Had a ping about tyre pressures for fronts so topped up all round to 33 front, 35 rear but despite a couple of decent journeys one rear still giving a warning despite other rear being same PSI (35) and not giving a warning? Possible TPMS issue?

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Macan S - MY23 - PRG1YBJ5 - (his)

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Scooby_Doo
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Col Lamb
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Post by Col Lamb »

Before you go on a journey reselect a different tyre in the Menu system.

After a few minutes, say 20 stop the car in a safe and legal place and restore the setting to original.

Then drive off again it may reset to normal.

It has worked for me in the past on the odd occasion that I have the fault showing and do not have a screw embedded in the tyre.
Col
Macan Turbo
Air, 20” wheels, ACC, Pano, SurCam, 14w, LEDs, PS+, Int Light Pack, Heated seats and Steering, spare wheel, SC, Privacy glass, PDK gear, SD mirrors, Met Black, rear airbags
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Tim92gts
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Post by Tim92gts »

I've found it a bit flakey but one issue is that the sensors seem to be very sensitive to temperature. Parking with only one side in full sun pushes the readings up quickly.

Haven't quite worked out whether this is due to a real increase in pressure or some compensation going on in the sensor.

I also had two warnings when i ran over a sleeping policeman faster than intended, settled down after a few days.
Tim
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Neil1911
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Post by Neil1911 »

P = VT ..... who's law us that? It's been soooooooo long! Tyre volume is constant(ish) so park a matt black object in direct sun it'll heat, quickly, and the pressure will rise in direct proportion to the temperature.
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Col Lamb
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Post by Col Lamb »

Neil1911 wrote: Mon Jul 08, 2024 6:53 pm P = VT ..... who's law us that? It's been soooooooo long! Tyre volume is constant(ish) so park a matt black object in direct sun it'll heat, quickly, and the pressure will rise in direct proportion to the temperature.
OMG
That takes me back more years than I care to think about, studying Thermodynamics.

General Gas Law
PV = mRT
Or another way
P1V1/T1 = P2V2/T2

Charles
P1/V1 = P2/V2

Boyles
P1V1 = P2V2

Then there is Dalton’s Law, which being a smart ass that I can be when my Boss asked me what it was I quoted it without hesitation, he never tested my Engineering knowledge again.
Col
Macan Turbo
Air, 20” wheels, ACC, Pano, SurCam, 14w, LEDs, PS+, Int Light Pack, Heated seats and Steering, spare wheel, SC, Privacy glass, PDK gear, SD mirrors, Met Black, rear airbags
Jon A
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Post by Jon A »

Col Lamb wrote: Mon Jul 08, 2024 8:02 pm
Neil1911 wrote: Mon Jul 08, 2024 6:53 pm P = VT ..... who's law us that? It's been soooooooo long! Tyre volume is constant(ish) so park a matt black object in direct sun it'll heat, quickly, and the pressure will rise in direct proportion to the temperature.
OMG
That takes me back more years than I care to think about, studying Thermodynamics.

General Gas Law
PV = mRT
Or another way
P1V1/T1 = P2V2/T2

Charles
P1/V1 = P2/V2

Boyles
P1V1 = P2V2

Then there is Dalton’s Law, which being a smart ass that I can be when my Boss asked me what it was I quoted it without hesitation, he never tested my Engineering knowledge again.
Is the rapid loss of pressure and volume in the middle of nowhere, Sod’s Law??
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Woodhouse
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Post by Woodhouse »

Col Lamb wrote: Sun Jul 07, 2024 6:16 pm Before you go on a journey reselect a different tyre in the Menu system.

After a few minutes, say 20 stop the car in a safe and legal place and restore the setting to original.

Then drive off again it may reset to normal.

It has worked for me in the past on the odd occasion that I have the fault showing and do not have a screw embedded in the tyre.
Cheers for the advice. I did something similar (selected full load, pulled over and put back to normal). Cleared all the issues. Seems like the sensors needed a reboot of sorts.
Macan S - MY23 - PRG1YBJ5 - (his)

F60 Mini Countryman Cooper S (hers)
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