Tire pressure sensing on Citroen C5 Aircross 2019 ?? sensor on the valve inside or ??

jaahn

jaahn

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A quick easy question. How does the Aircross sense the tire pressures. It knows there is a low pressure and then it acknowledges the space saver spare is on and turns off the driving aids. How ? A family member clipped a sharp edge on a curb and f*cked a front tire on my 'new' Aircross. Hmmmnn :rolleyes: :mad::whistle:
These things happen ! The "special" Michelin tires on the car are not readily available but there was one shown in Sydney. However when it was ordered by the person at a tire shop they could not find it ???WTF ? So one might come from Brisbane warehouse next week.

As a result the tire shop stripped the tire and put the rim in the back well. When i looked at it today I note that there is no pressure sensor on the rim or the valve stem. Should there be one there somewhere or does it use magic software to get the pressure readings. I wish to know this before the new tire arrives PLEASE.(y)

On another tack going down the worm hole. This morning the space saver spare is going flat slowly and I see a screw in the tread. Put some soapy water on it and yes it is leaking, bugger !(n)o_O I noticed it because of the rythmic noise as I drove and looked carefully at it. It sounded OK when I drove it home from the other house Thursday night. It never rains but it pours is an old saying.
Jaahn
 
TPMS systems work by periodically broadcasting a UHF radio signal, with the data encoded in a packet which includes the unique MAC address of the sender hardware. Since each wheel hub has a separate receiver the computer detects if the wheel is changed.

Wireless networked computers work similarly. Every request includes the MAC address of the computer.
 
Thanks but I guess I am asking if the Aircross might have this instead ?
https://www.bridgestonetire.com/learn/maintenance/tire-pressure-monitoring-system-how-tpms-works/
INDIRECT TPMS: WHAT IS INDIRECT TPMS & HOW DOES IT WORK?
An indirect TPMS typically relies on wheel speed sensors that the anti-lock brake system uses. These sensors measure the rate of revolution each wheel is making and can be used by on-board computer systems to compare with each other and to other vehicle operation data such as speed.
Based on the rate of revolution of each wheel, the computer can interpret the relative size of the tires on your vehicle. When a wheel starts spinning faster than expected, the computer calculates that the tire is underinflated and alert the driver accordingly.
So, an indirect tire pressure monitoring system doesn’t actually measure tire pressure. It’s not electronically processing the same kind of measurement you might see with a tire gauge. Instead, an indirect tire pressure monitor simply measures how fast your tires are rotating and sends signals to the computer that will actuate the indicator light when something in the rotation seems amiss.
 
jaahn said:
A quick easy question. How does the Aircross sense the tire pressures. It knows there is a low pressure and then it acknowledges the space saver spare is on and turns off the driving aids. How ? A family member clipped a sharp edge on a curb and f*cked a front tire on my 'new' Aircross. Hmmmnn :rolleyes: :mad::whistle:
These things happen ! The "special" Michelin tires on the car are not readily available but there was one shown in Sydney. However when it was ordered by the person at a tire shop they could not find it ???WTF ? So one might come from Brisbane warehouse next week.

As a result the tire shop stripped the tire and put the rim in the back well. When i looked at it today I note that there is no pressure sensor on the rim or the valve stem. Should there be one there somewhere or does it use magic software to get the pressure readings. I wish to know this before the new tire arrives PLEASE.(y)

On another tack going down the worm hole. This morning the space saver spare is going flat slowly and I see a screw in the tread. Put some soapy water on it and yes it is leaking, bugger !(n)o_O I noticed it because of the rythmic noise as I drove and looked carefully at it. It sounded OK when I drove it home from the other house Thursday night. It never rains but it pours is an old saying.
Jaahn
Click to expand...
I tire of tyre misspelling!
 
This site agrees with indirect:

CITROEN - ATEQ TPMS

TPMS tools for Toyota vehicles
www.ateq-tpms.com www.ateq-tpms.com

Is the spacesaver significantly different in radius, eg larger? That would give the system a clue.
 
Indirect detection in the C5 Aircross without the individual pressure sensors. The system looks for a change in the diameter of the wheels or in the physical behaviour of the tyres.

The minimum vehicle speed threshold for detecting a fault is 40 km/h.
The system is not active when stationary.

A deflation detection is detected if the pressure is diminished by 20% relative to the pressures registered on initialisation.
Example :
If the pressures in the vehicle’s front tyres are programmed at 2,4 bars, the tyre deflation alert will apply at around 1,9 bars
If the pressures in the vehicle’s rear tyres are programmed at 2,2 bars, the tyre deflation alert will apply at around 1,8 bars
 
Our VW group cars have the indirect method, ie: it uses data from the abs wheel sensors to detect any variation in wheel rotation speeds, and puts a warning on the screen if the difference exceeds what is expected.

It is surprisingly sensitive, has detected when I rotated tyres and put a warning on the screen, because it noticed a change in the relative speeds of front and back wheels. If you check tyres/pressures and all is ok, you can press a "tyre reset" button on the dash and the computer is told "what you are measuring now is correct." If you adjust tyre pressures, swap tyres around or get new tyres, you have to reset to tell the computer that this is the new normal.

SuppleC - I'm getting a red wriggly line underneath every time I write "tyre." I think it is my browser using US spelling. D'oh.
 
I was astounded a week ago, the now 18 year old C5 alerted me to a low tyre pressure and illuminated the car "map" on the info screen .... the source of the amazement was the fact that the in wheel black box sensors still work, with no change of battery. I don't even know if battery replacement is possible ... but the TPMS has saves or alerted us to slow leaks 4 times over their lifetime. The system is well worth having. I have always informed the tyre "technicians" of their presence at tyre replacement times.
 
They are sealed, so no new batteries. Tyre places should notice them, as the protruding valve stem is different, but play safe and tell them, particularly if they don't do many Euro models.
 
SuppleC said:
I tire of tyre misspelling!
Click to expand...
Hmm Wiki.:unsure:
A tire (North American English) or tyre (Commonwealth English) is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which the wheel travels.

Anyway thanks to you all for your helpful replies. I will accept that the tyre shop did not remove the sensor, why would they ? :rolleyes: I await my over priced tire(sorry tyre) to arrive if they can find one !
I will now go out and plug the screw hole in the flat spacesaver spare so I can drive it. At least it is sunny now !:cool:
cheers Jaahn
 
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An update on the tyre pressure monitoring. My car had sensed that the spare wheel was on after it was fitted, it is obviously a smaller dia, and it gave a message. Every start it said check tyre pressures and reset. Then after driving a short while it gave a message spare wheel fitted , driver aids disabled. So no cruise, or lane warnings and ?? No problems really and an extra incentive to get the tyre fixed. :unsure:
I was concerned what to do to reset the monitoring after the new tyre was fitted. Same warning after start, but after starting to drive the spare wheel warning went off quickly and as i drove on it just reset itself and turned the aids back on after a short time more. No driver intervention needed. Hmm seemed all good.
The new original tyre certainly runs smoother and less noise than the emergency spare did. That would be by design probably !! :rolleyes:
Jaahn
PS just a comment on the charges at the tyre shop. I presented with a bare rim in the boot for the new tire. They still charged me for a tyre disposal fee of $9.10. I did not notice it then but will get it back from them today, as I did last time they did the same charge. It is a standard fee the computer puts on the bill. But they agreed it was not justified. The tyre was removed at another shop.
 
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