Checked my tyres and pumped to 38psi about 10 days ago, and reset the tpms. Just driving across London to the station and 3 miles into the journey tpms activates and says check rear left tyre. I pull over, it looks OK and since I'm on the way to the station to drop the fiancée for a booked train I got back in and reset tpms. I didn't go off again in the rest of the 15 or so mile journey but got the compressor out once home and.... 21psi...oh.

 

It's Sunday night and cold, I don't need the car tomorrow... It's now pumped back to 38psi with tpms reset and away in the garage but what's the odds on a nail or screw? Hopefully a repairable puncture if I've any luck.

 

At least I know tpms works, and it seems to need a fall of about 16 or 17 psi to activate it.

Bummer! I had a nail in recently (stuck in so a slow leak). The TPMS went off with a drop of 8psi (32 from 40 - I'm on Xtremes). It did it 3 times at the same pressure drop. After 3x losing 8psi over 24h I begrudgingly acknowledged that I needed a trip to the dealer...

As an aside, the dealer charged me $35 to fix the flat. I kind of expected to have it done for free, it was less than a 10min job. Many tyre shops do it for free in NZ, on anyone's car. Obviously Skoda make money from servicing, but I thought fixing a flat might have been a freebie. If I'd have known in advance I would have taken it to a tyre shop. My fault for not checking though!

Edited 19 January, 201511 yr by kitset

TPMS inform me of rear left (300 miles on the clock).  Pressure was 12psi.  Pumped it up, reset it.  Went off 5 mins into next journey.  Nail in tyre wall, new tyre required.  Glad I didn't have to pay for it - would have cryed at that mileage needing a new one.

Yes, for all the people that complain about warning messages, when you use it properly it seems to work very well.

Also living in a country where its common to have winter wheels/tyres its much better than other systems which require expensive sensors to be fitted inside the wheel.

Yes glad to have the system now, at 21 psi the tyre looked and felt fine so I hadn't spotted it, tpms would seem to give plenty of warning. Had I been on a motorway or busy a road after stopping for a visual inspection I would have, in this case, been able to safely proceed a short distance to a safe place to pump it up or fit the spare. I like that it gives this warning.

Yes, for all the people that complain about warning messages, when you use it properly it seems to work very well.

Also living in a country where its common to have winter wheels/tyres its much better than other systems which require expensive sensors to be fitted inside the wheel.

 

Could you tell me how the system monitors the pressures please?

The TPMS is an indirect system.  It does not directly monitor tyre pressures, but rather uses the ABS wheel speed sensors to detect if one wheel is rotating at a markedly different speed to the others.

 

http://en.wikipedia.org/wiki/Tire-pressure_monitoring_system#Indirect_TPMS

Thanks. So quite important to check the pressures are correct when new, reset the system and drive for quite a few miles while the system learns the 'normal' behaviour of the tyres. 

The TPMS is an indirect system.  It does not directly monitor tyre pressures, but rather uses the ABS wheel speed sensors to detect if one wheel is rotating at a markedly different speed to the others.

 

http://en.wikipedia.org/wiki/Tire-pressure_monitoring_system#Indirect_TPMS

Thanks for the info. Have been finding my TPMS (Octavia III) is a bit fiddly at times. For instance, last week, I went over something on the road and about 30 seconds later reached destination and parked up for about 30 minutes. Came out and drove off (it was a poor night so moving slower than normal). About a minute into my trip, I could feel steering was off so pulled in on a forecourt and found front left was nearly completely flat. Turns out I'd blown the sidewall when I hit whatever I hit. I would have thought that that kind of change would have caused the TPMS to tell me something? Any ideas would be helpful - thanks!

Its a great system and does what it says on the tin....provides some forewarning of an issue but naturally will not be any good for rapid deflation situations.

Ive had two situations where its worked great.

Once on my old Fabia vRS...after the notification came on I hobbled the mile or two left to work to get out the car to hear the tyre deflating...it identified an issue and gave me the oportunity to get somewhere local (though I admit to continue driving was a little bit of a risk).

2nd time was in motorway in my O3.....indicated low pressure in my rear right tyre (love how it now tells you what wheel is affected) I pull over open the door and sure there is the hissing and in couple of mins its as flat as a pancake.

Im glad its been made a legal requirement as I personally would not want to own a new car without the tech now...it can literally prove to be a life saver!

The TPMS is an indirect system.  It does not directly monitor tyre pressures, but rather uses the ABS wheel speed sensors to detect if one wheel is rotating at a markedly different speed to the others.

 

http://en.wikipedia.org/wiki/Tire-pressure_monitoring_system#Indirect_TPMS

 

 

Its a great system and does what it says on the tin....provides some forewarning of an issue but naturally will not be any good for rapid deflation situations.

Ive had two situations where its worked great.

Once on my old Fabia vRS...after the notification came on I hobbled the mile or two left to work to get out the car to hear the tyre deflating...it identified an issue and gave me the oportunity to get somewhere local (though I admit to continue driving was a little bit of a risk).

2nd time was in motorway in my O3.....indicated low pressure in my rear right tyre (love how it now tells you what wheel is affected) I pull over open the door and sure there is the hissing and in couple of mins its as flat as a pancake.

Im glad its been made a legal requirement as I personally would not want to own a new car without the tech now...it can literally prove to be a life saver!

Seems odd then - if as says above uses the rotational speed to determine a change, wouldn't rapid deflation, or in my case, a nearly flat tyre give rise to a huge change between the rotational speeds?

 Seems odd then - if as says above uses the rotational speed to determine a change, wouldn't rapid deflation, or in my case, a nearly flat tyre give rise to a huge change between the rotational speeds?

 

Yes - but there are *many* things that will give a difference in rotational speed, such as bumps, cornering, poor traction etc.  To avoid spurious errors the system looks for significant differences in wheel speed over a period of time, rather than instantaneously.  Hence it will not trigger on a rapid deflation.  This is not as much of a problem as it might initially sound: as you've found out, a rapid deflation is very noticeable to the driver.  The slower, gradual deflation is much harder to detect, and indirect TPMS will pick that up, usually with enough warning for you to get somewhere safe to deal with it.

Yes - but there are *many* things that will give a difference in rotational speed, such as bumps, cornering, poor traction etc.  To avoid spurious errors the system looks for significant differences in wheel speed over a period of time, rather than instantaneously.  Hence it will not trigger on a rapid deflation.  This is not as much of a problem as it might initially sound: as you've found out, a rapid deflation is very noticeable to the driver.  The slower, gradual deflation is much harder to detect, and indirect TPMS will pick that up, usually with enough warning for you to get somewhere safe to deal with it.

Thanks for elaborating!

My issue turned out to be a clout nail. Thankfully it was in a repairable position.

The screw in mine was too close to the edge.   New tyre to be fitted to match the others (450 miles old) £101 !!!!

 

Michelin Primacy HPs fitted as standard. Apparently fairly good (but older) tyres? 

The screw in mine was too close to the edge.   New tyre to be fitted to match the others (450 miles old) £101 !!!!

 

Michelin Primacy HPs fitted as standard. Apparently fairly good (but older) tyres? 

 

Ouch! I had to replace my front left last week as pre above, 3,500Km old. Conti Sport Contact 5, to match the others as you said.  :peek:  it was terrible news!

I feel your pain!  I hit a pothole in my (then) 2 week VRS, Nov 2014.  Took out the sidewall in both left tyres - 19" Xtremes with p-zero's.  That hurt the wallet!  The tyre shop didn't have any match pzero's.. in hindsight I should've fitted something grippier like the F1A's, which were cheaper too.

 

I'm now extra careful with road surfaces in the outer suburbs of Melbourne!

Edited 3 February, 201511 yr by chriskan

feel for you. I was nervous as i headed to kwikfit, but thankfully the nail was found slap bang in the middle of the tread, phew!

Thought I'd come back on this one....TPMS been complaining about the rear right so kept an eye on the pressure and turns out in the end broken nail rammed deep slap bang in the middle of the tyre. Guy in the garage nearly couldn't find it. Sorted, cheap and cheerful but bottom line is pressure drop was gradual and only small but TPMS wen't off reliably and did exactly what it should have done.