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Does anyone know if there's a fault with the tyre pressure monitoring? I had it set to 32 PSI and had a puncture. The light never came on and only noticed the puncture one evening. Got it repaired and checked all tyres to find them all below 20 PSI.

zach.lambert wrote: Wed Feb 27, 2019 10:14 am Does anyone know if there's a fault with the tyre pressure monitoring? I had it set to 32 PSI and had a puncture. The light never came on and only noticed the puncture one evening. Got it repaired and checked all tyres to find them all below 20 PSI.

Indirect TPMS only works if 1 tyre deflates while the others stay inflated. If all 4 tyres deflate then it won’t warn you.
This is due to how it works using the ABS wheel sensors, comparing each wheel rotation.
You still need to manually check your tyre pressures regularly.

Direct TPMS systems have a pressure sensor mounted in each wheel. This can tell you the exact pressure and monitor each wheel individually. It’s possible to retrofit this.

Hi, I think the polo has tyre pressure loss sensors.
It uses wheel speed sensors to work out if a tyre has lost air.

If all tyres were at a similar pressure, the car may not have noticed they were low.

To test if it works, inflate all tyres to correct pressure, reset the tyre monitor in the car's menu, and drive around for a bit.
If you let out air from a tyre and drive on it, the system should notice the squishy tyre as it's wheel speed will be different.
Thanks

I see,it seems strange as to how all the tyres lost alot of pressure in them in such a small amount of time. Maybe it's down to the tyre material and makeup too.

How long passed between you setting them at 32psi and noticing they were at 20psi?
Weather, especially cold weather, plays a large part in tyres losing air.

Andy Beats wrote: Wed Feb 27, 2019 1:54 pm How long passed between you setting them at 32psi and noticing they were at 20psi?
Weather, especially cold weather, plays a large part in tyres losing air.

The tyre doesn't lose air in the cold weather, but the air pressure will be lower for a given quantity of air in a fixed volume if the temperature is reduced. That's Boyle's law of gases

That being said, I wouldn't expect a drop of more than around 5psi between 20C and 0C ambient temp.

Be interesting to know how long he noticed the pressure drop over and his make of tyres.
Assuming it's the same tyres on all four wheels and equal pressure drop over all four, they must just be a particularly 'porous' brand.
Porous or permeable, whatever the correct term is for rubber.

A couple of months went by. It was only when we spotted the puncture we checked all of them again. The tyres on there are falken S ones. Soft sidewall even when fully inflated.

zach.lambert wrote: Wed Feb 27, 2019 4:38 pm A couple of months went by. It was only when we spotted the puncture we checked all of them again. The tyres on there are falken S ones. Soft sidewall even when fully inflated.

32psi down to 20psi in a couple of months doesn't strike me as excessive.
It's only 6psi a month, that's not crazy.

Andy Beats wrote: Wed Feb 27, 2019 4:53 pm

zach.lambert wrote: Wed Feb 27, 2019 4:38 pm A couple of months went by. It was only when we spotted the puncture we checked all of them again. The tyres on there are falken S ones. Soft sidewall even when fully inflated.

32psi down to 20psi in a couple of months doesn't strike me as excessive.
It's only 6psi a month, that's not crazy.

Never had a tyre lose pressure like that - it's excessive. If it was on a older car, I'd suspect interior corrosion on the wheel rim, making a poor seal to the tyre.

Andy Beats wrote: Wed Feb 27, 2019 3:18 pm Be interesting to know how long he noticed the pressure drop over and his make of tyres.
Assuming it's the same tyres on all four wheels and equal pressure drop over all four, they must just be a particularly 'porous' brand.
Porous or permeable, whatever the correct term is for rubber.

Whatever the correct term is, I hope they don't make condoms!

Possibility they were checked and adjusted but didn't reset the TPMS, outside temperature will play a part as already suggested, also if pressures were checked and set when tyres were cold or after a journey. Hope you get it sorted without too much expense!

I have had a couple of false alarms from the TPMS - checked an all tyres were spot on no drop in pressures. I have topped them up and reset it but it's a bit random. My previous Fiesta had the actual valve monitoring system in each wheel (indicated by a yellow sticker on the alloys) which seemed a more accurate system. Another gimmick I suppose if it's not reliable. At least most Polos have a proper spare tyre instead of the pump and glue kit so popular now in case you do get a flat.

Muldoon wrote:I have had a couple of false alarms from the TPMS - checked an all tyres were spot on no drop in pressures. I have topped them up and reset it but it's a bit random. My previous Fiesta had the actual valve monitoring system in each wheel (indicated by a yellow sticker on the alloys) which seemed a more accurate system. Another gimmick I suppose if it's not reliable. At least most Polos have a proper spare tyre instead of the pump and glue kit so popular now in case you do get a flat.

All models, bar the beats [emoji107].

The sensor within the wheel I thought would be the norm, despite being expensive when a tyre company breaks them they're usually ok. The vans at work have around 50k on and are yet to be an issue (on a 65 plate). Shame VW didn't include that.

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