Hi

I expect this is a dumb question (and yes I have searched for an answer, but not been successful)

How does the tyre pressure monitoring system work?

Will the fitting of winter wheels (be they steel or alloy) affect that.

My better half has run flats on her 320d and this has tyre pressure monitoring on it. I have seen that it is a requirement for run flats.

Cant see any difference in the valve caps, is there some sort of port and spigot in the wheel itself?

Also I have read that MOT's in the future will be checking these systems if fitted, if the wrong wheels are on and it doesn't work then its a failure - I guess!

Edited 8 May, 201214 yr by vegit8

Pretty certain it works by reading the wheel sensors for ABS etc and looking for a difference in wheel speed consistent with low pressure. There is no connection with the wheels/tyres.

If it is like the system on my last Seat it isn't very sensitive.

Reads off the ABS, daft thing is it's there on all models, and can be activated via VCDS. BUT... you pay extra for the 're-set' button - or of course you can re-set it each time via VCDS !!

I had a Renault Laguna sport tourer 2.0ltr diesel when they first came out. When you turned the ignition on it gave a readout of the pressure in each tyre. I believe there was a sensor of some sort in the wheel valve, but don't ask me how it worked, but it did, and very well.

There are active and passive systems - the Renault one described is active and relies on sensors in the wheels which communicate by short range radio to the car. The BMW and (I assume) VAG system is passive and rely on reading wheels speeds via the ABS sensors and spotting anything unusual - these need to be reset when you change wheels or tyres, or even when you pump them up (although this is rarely actually necessary).

I don't want to have to get the manual out of the car especially on crutches (going for the sympathy vote!) how do you do a reset cos I reckon I might get my Summers back on in about 4-5 weeks?

Hold the button down with ignition on until it boings.

Hold the button down with ignition on until it boings.

And stationary; will not reset on the move.

TP

Well added that man

Hold the button down with ignition on until it boings.

Thanks - Bizarrely even though I paid for the option I forgot there was a button :think:

Do a search for TPM... You'll find plenty on it. I'm glad I have it as it is not expensive but do I find it works? Nah. Sensitive it is not. It takes AGES to detect anything and when it does it does not tell you which wheel (though it knows EXACTLY which wheel it was of course!). Many people on here have driven miles and miles before it so much as beeped. And in some cases people have had a totally deflated tyre and still it did not activate!!!!!!! So it gets a 2 out of 10 rating from me as to its effectiveness. Pretty much useless in my book.

I don't have it on the Yeti but do on the B Class - this picked up a slow puncture before it looked or felt soft. That said, I wasn't impressed enough to order it on the Yeti!

...though it knows EXACTLY which wheel it was of course!

Yes - that's really annoying. When mine went off on the octavia, i couldn;t tell in the dark/rain which one it was. I drove home slowly and got the pressure gauge out and it was down to 22 (although who knows how much of that was lost in the 7-8 miles i drove after it came on.

Edited 11 May, 201214 yr by sdenny

Had mine come on, had to check 3 tyres before I found the right one, it was down to 1.2 bar. Pumped it up and travelled about 6 miles to the nearest Tyre Fitters and in that time the punctured tyre had not deflated by more than 0.1 bar so the original warning had taken a long time to register. It was a rear wheel and I had not noticed any change in the handling but it was a straight road with a 50MPH limit.

TPM probably saved the tyre as it turned out to be a simple repair once the nail was pulled out.