Tyre warning light came on - Nothing seems to be wrong.

[jtmac]

Last night while going down the M1 at 70(ish) my tyre warning light came on. I start carefully slowing down and turn the radio off. The car feels and sounds completely normal so I don't fancy stopping in the hard shoulder just a few hundred yards from the next exist so I come off the motorway and drive like a grandad towards the first residential street where I look at the car and the wheels all look alright. I go off to next garage and all my tyres are above normal presure because they are still warm but most importantly they match left and right.

So I set off again re-assured and pressed the reset button near the handbrake and the warning light has stayed off.

If I remember right from the manual the warning light works by counting the revolutions of each wheel and if one wheel starts spinning quicker than the other three it guesses that that wheel must be flatter than the other three.

Does anyone know why this would give a false alarm?

I'm going to chuck a pressure gauge in with the sealant and air-compressor kit that is in the spare-wheel space. If I hadn't been near a garage I don't know if I would have trusted the gauge built into the little air compressor.

I might get myself I hi-vis vest and put it in the little glove-box under the seat too.

 

[RJS]

Our that,s what that button is for thanks.

 

[klawit]

hi jtmac,

had the same phenomenon approx. 18 months ago ... checked just as you did with same results: all tyres same constant and correct pressure.

Re-calibrated and never had a warning again since ... ok, have to mention that I do change wheels (summer/winter) twice a year including calibration afterwards.

I posted this incident at german board and even our electronics guru couldn't explain what & why ... just the assumption, that a former calibrating process probably hadn't finished properly.

greets ... Klaus

 

[jtmac]

Thanks Klaus,

I had replaced my front tyres about 3000 miles ago. and I hadn't re calibrated (didn't realise it might be necessary). Don't know it the tyre fitter had but I expect not. maybe that was it. If it had been that I would have expected the warning sooner but maybe there wasn't much difference between my orginal bridgestones and the new Fuldas.

slighlty deviating from topic would you know if this sensor the sensor that you would need if you wanted to use run on flat tyres or do you need an actual pressure sensor? I don't think i'd bother with run on flats but it did cross my mind considering that I don't have a spare.