2008 tyre deflation warning symbol mystery

BarryC

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Fellow Frogger
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267
Location
Melbourne
Was driving back to Melbourne on a fairly smooth dirt road when the tyre deflation warning symbol turned up. Got out of the car - nothing seemed amiss, so drove at a slightly more relaxed speed for 20K to a service station. No obvious tyre deflation.

Checked all my tyres which were hot but within 2 PSI of each other and were around 34-35 PSI (hot). Seemed pointless to add pressure to a hot tyre or 4. So I simply pressed the "reset" for tyre deflation warning and drive back to Melbourne with no further issues.

I haven't even checked all tyre pressures when cold yet.

Since the tyre monitor works by sensing differences in rotational speed for each wheel, I wondered what might have been the cause? All I can think of is 1) some slight difference in rotational speeds of one of the wheels because of dirt roads - although this hasn't happened (on worse dirt roads than this one) before in 20K. 2) faulty sensor in one of the wheels?

Any thoughts?

I may just ignore it until it happens again - hopefully still under warranty ......
 
I e seen this system warn at 4 psi low it’s pretty sensitive so possible the dirt road might have played a part but doubtful


Garage C5 X7 3008 XTE
Gone but not forgotten 206 GTI 180 306 XR SED 405 MI16 x2 xzara VTS 406 SV 206 XT Berlingo 2011 (best car ever) 306 HDI 307 XSE HDI touring
Fix it right the first time
 
I dismantled a failed sensor from a Citroen of similar age last year and it had a button battery sealed inside and a small hole leading to what I assume was the pressure sensor. While the battery was made in Japan, I doubt it will last forever an it was obviously not designed to be changed. I presume owners will simply have to disable the system when they tyre (sorry) of buying expensive replacement sensors.

On at least some versions of these sensors, the neck is a separate part too, so it can be changes separately if required.
 
Perhaps my post was a little imprecise. My car is a Peugeot 2008 (the upgrade with the 1.2 3 cylinder turbo) I bought it in 2017.

My understanding is that the sensor is a wheel rotation sensor - not an actual air pressure sensor in the valve(?) as your response seems to imply. Sorry if I’ve got the wrong end of the stick.

Cheers
 
Expecting a pressure sensor comes from that being the norm in the Citroen C5 and Peugeot 508. These cars have a pressure sensor which transmits its reading by radio. These cars also have a rotation sensor at each wheel, which is part of the ABS/ESP system. The valve stems are different from the ones used by simple valves.

Online sellers offer batteries for 2008 PTMS so I guess they are similar to the other cars from PSA.
 
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Sorry, I read 2008 as a year, not the model! Best action here is to have it fixed under the new car warranty. The battery in the unit I dismantled required destruction of the casing to get at.
 
Thanks, David. Seems that you think it's a wheel speed sensor problem too. I may wait until it happens again, perhaps, then get it done under the 3 year guarantee I still have.

Cheers
 
If it was a wheel speed sensor problem you would get esp faults it’s more likely to have slightly low pressure I’ve never had a problem with this system but again they are very sensitive


Garage C5 X7 3008 XTE
Gone but not forgotten 206 GTI 180 306 XR SED 405 MI16 x2 xzara VTS 406 SV 206 XT Berlingo 2011 (best car ever) 306 HDI 307 XSE HDI touring
Fix it right the first time
 
I'm thinking the reset button does all the fixing you'll need. The sensors occasionally get out of whack for unknown reasons, so if you've checked the tyre pressures and they're OK a simple reset does the trick.
 
Its not really a reset button but a recalibrate, when was the last time it had been pressed? You're supposed to press it each time you pump up the tires.
 
What if I said that I’d never checked the tyres because they always seemed ok and the warning had never occurred? ..... (blush) ..... I won’t say that, then.....
 
You won't be the only one to not say it. The sensors will always warn you of a drop in pressure. No drop of pressure, no warning. No warning = tyres still at correct inflation pressure. I guess we don't recalibrate our oil pressure warning switches weekly for the same reason......
 
The 2008 doesn’t have pressure sensors they use the wheel speed to calculate pressure that’s why they need to be reset after adjusting tyres


Garage C5 X7 3008 XTE
Gone but not forgotten 206 GTI 180 306 XR SED 405 MI16 x2 xzara VTS 406 SV 206 XT Berlingo 2011 (best car ever) 306 HDI 307 XSE HDI touring
Fix it right the first time
 
True about wheel speed. I was on a fairly smooth dirt road, but I suppose that corrugations could affect the speed of one wheel compared to the others. That would be enough to trigger it, I expect. Probably only needed the discrepancy for a second or so?
 
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