Coming home last Friday the puncture alarm went off, so I checked all tyres, couldn't identify which had triggered the alarm and continued home at 80kmh. Went to the garage Sat and topped up the four wheels, all were a bit low but nothing exceptional. I reset the pressure sensor and no more puncture alarm! On Monday I again checked the pressures at the garage but no change in the tyres.

Does the puncture alarm system give any indication of which wheel it suspects is punctured?

For now, I'm just hoping it was a glitch, but it might be a slow puncture.

Does anyone else think that run-flats are a step backwards?

 

No. not really why would you say so.
It is generaly not a puncture alarm, more an advanced warning to low tyre pressure, it will coming on if there is a variation in tyre pressures, not just if you have a full flat tyre. if your pumped them all up and re set the system there is no need generaly to check them again.

 

+1. TPS is not a puncture alarm - it is a tyre pressure monitoring system and by the sounds of it did exactly what it was supposed to do by alerting 'Irishman' that his tyre pressures were a bit lower than the parameters allowed for by the system.

 

My experience over the past 18 months is that they don't always work when they ought to (I had a complete flat and the system did not trigger) and they sometimes trigger when they shouldn't (check pressures - reset system - no further triggers for 3 months...) but on average they do work. Whether it is worth the irritation of a false alarm in return for the peace of mind that the system is checking things is a personal opinion.

As for the question of whether RFTs are a step backward... again it's the peace of mind trade-off. I know that when I had a tyre go on the Autobahn loaded up with family on the way to Austria, I was glad of the ability to just drive to the nearest exit. (never mind that I couldn't get a replacement tyre because in the UK we use "Summer" tyres all year.....)

If I was convinced that RFTs were a retrograde step I'd probably have swapped them by now - so I suppose I'm happy to take the peace of mind option and put up with the idiosyncrasies of the tyre pressure warning system.

 

exactly. it is a new technology that for myself i feel is a step in teh rigth direction for safty and peace of mind. Sounds like you may have a dodgy sensor djone.

But personal i think there all fairly handy.

 

I looked up the manual (always a good start ) and it doesn't directly measure pressure, it monitors the wheel rotation rate and if the pressure is lower, the wheel circumference is smaller and tus the rotation of a wheel will be different to that of the other three wheels.

By that then I guess it won't detect if all tyres were, for example, 20% under inflated as they'd all have the same rotation rate. I also presume this can only be detected in straight line driving.

Finally, the warning that comes up on iDrive in big red letters was "Puncture Alert!" - not a pressure alert. But thats a pedantic point.

 

I too had this same alert come up over the weekend.....all tyre pressures were checked and no loss what so ever!

Reset from the I-drive and hopefully it has now disappeared (finger X'ed)

 

My '08 (LCI) tells me which tire is low on the display (display shows the car, all 4 tires in green, except the low tire which is in yellow). Is that new to the LCI?

 

But it grabbed your attention though!

 

Sounds like that's a new development, and a good one too.

I don't know if the puncture system in the US is the same as Europe though. My understanding is that the US are legislating puncture detection on all new cars from '08 and inferred information (i.e. wheel speed) does not comply with the regulations. I know that Ford use a sensor mounted in the rim which has battery (that's going to be fun when they start going flat... ) and it transmits a pressure signal to the car when it rotates. These are mounted on the rim with a steel band and from our experience so far, they are a PITA. The car has to recognise its own sensors so you have to swap them round if you change wheels too.