My new octy has TPM fitted and I was wondering how it worked.

Obviously there is going to be some kind of sensor somewhere on the wheel area but where is it and what does it do?

Can you still get tyres changed anywhere?

What about if you need a new wheel?

I can check the handbook later, but I remember it saying something about it not actually sensing pressure, but working on the rolling circumference of each tyre.

if it get's smaller, then there is less air so it warns you. I checked my tyres before a scotland trip a couple of weeks ago and reset the TPM, and checked them again before blackpool and still the same pressure.

I'm not going to let a tyre dowen to see if it works though :D

The system works off the ABS sensors that measure the speed of the rolling diameter of the wheel, if one wheel deflates the speed of rotation will change.

This system is a lot more reliable than more complex systems that use pressure monitoring valves, but if all your tryes drop in pressure at a slow and even rate, the system might not pick up the drop in pressure as the speed of each wheel remains the same. So this type of system is only good for telling you that you may have a puncture, but you should not rely on it as a means of not ever checking your tyre pressures as normal.

Hmmm , so it's actually all done in software then.

The £50 they charge for it is actually money for old rope

The

I had a nail in my tyre a while back (slow puncture) and the system alerted me as soon as I started driving:thumbup:

I had a nail in my tyre a while back (slow puncture) and the system alerted me as soon as I started driving:thumbup:

That happened to me too, same result tyre pressure monitor picked it up straight away but to the naked eye everything looked fine!.

I wonder how much does the pressure need to drop by before its recognises a pressure drop.

That sounds way better than the awful system I had in my late and not lamented Laguna. That used special tyre valves which transmitted the pressure back to a central receiver which was held on to the underside of the bodywork with 2 plastic clips. Going through any sort of standing water at high speed would result in the thing unclipping and then dangling from the underside of the car by its wire. The clunking noise usually gave the game away....

Then there was the time I had a puncture, stopped when the warning light came on, replaced the flat tyre with the spare and put the flat in the boot, got back into the car, drove for about 400 yards when the stop light came on along with a warning that the tyre was flat again. Of course, like an idiot, I stopped the car and got out to check - not realising that the computer was monitoring the still deflating flat tyre in the boot, not the spare tyre that I'd just fitted to the car.

Boy am I glad I gave up driving the Laguna Mk2...!

I wonder how much does the pressure need to drop by before its recognises a pressure drop.

As little as four PSi apparently.

Not sure how accurate that info was though.

As little as four PSi apparently.

Not sure how accurate that info was though.

Can it be retro-fitted?

Can it be retro-fitted?

Shouldn't be a problem in theory. A switch for the dashboard, maybe a control module and some Vag-COM reprogramming. The rest is all there in the car already. It's only a

What sort of warning indication do you get when the tyre pressure is too low? The manual says the warning light lights up, nothing about an audible warning or any message in the information display. If it's simply the switch lighting up then I imagine it's easy to overlook. A ping with an appropriate message would be useful.

What sort of warning indication do you get when the tyre pressure is too low? The manual says the warning light lights up, nothing about an audible warning or any message in the information display. If it's simply the switch lighting up then I imagine it's easy to overlook. A ping with an appropriate message would be useful.

It's an indicator on the dash that sort of looks like the 'handbrake on' one but with a little image of a flat tyre between the brackets instead of an exclaimation mark. You get get a ping like you do when the low fuel indicator comes on. No text message on maxidot though as far as i'm aware.

My warning light came on on saturday but didn't notice any ping. Its quite noticeable if you reguarly check your speedo.

I my case it came on because after resetting the tyres (having checked them beforehand and adjusted them from fully laden (as per delivery) to the more normal lighter load of 2 people I had not reset the tyre pressure button.

The warning light came on after about 12 miles at 70 mph on a dual carriage way so presumably trigger when hot rather than when cold. The tyres pressures were consistent all the way round so I reset and continued.

Since resetting the monitor has not come on again.

Is there something like a 2 stage warning, the first for a slight drop and a more urgent alarm if there is anything more serious going on?

You would think there would be an urgent warning especially as it monitors the all important tyres:rolleyes: .