Tyre pressure monitor

[Mr Pig]

Sorry if this has been done but I just wanted to flag up how poor the tyre pressure monitor is.

The way the system works is actually quite clever, and simple. The expensive way to monitor your tyres is to have sensors inside the tyre which transmit the actual tyre pressure to the car. The Leon doesn't do that!

What the Leon does is look at the numbers coming off the ABS sensors to monitor the rotational speed of each wheel. If a tyre looses pressure the effective diameter of the wheel will get smaller and the wheel will rotate faster for any given road speed. The combluter notices that this wheel is spinning faster than the others and flags up the low pressure in that tyre. Clever, simple and cheap! Basically all that's needed is software in the ECU. The necessary hardware is already fitted to all cars with ABS. Great, except that it's a bit crap!

The service manager at the dealership told me that the system is quite sensitive, but it's not. I've been guilty of getting lazy and not checking the pressures, as I was told the monitor would pick up a loss of even a couple of psi. Imagine my surprise when I checked the tyres today and found them all down to between 20 and 25 psi!

I reckon the monitor might compare the tyre rotational speeds to each other, rather than to a reference for a given speed, so if all tyres are low it can't see it. Whatever the deal is, the system can't be trusted. So it's back to checking the tyres every week or so for me.

 

[kiddo]

Have you sync'd the tire pressure system after inflating your tyres?

 

[chrisRibiza]

Mine came on last week when my tyres hit 27psi. I'm happy with that TBH!

 

[stu_m]

On my Ibiza I had it was exactly the same system

I was trundling along the motorway when the pressure sensor came on!

upon checking the tyres every tyre had lost 3psi!!

I thought it was pretty good to pick up a 3psi drop and for all the tyres to be the same pressure it can't just be comparing them!

as above have you actually sync'd it?

 

[UTCIAD]

Two days after I took delivery of my new Cupra 280 in July 2014 the car warned me of low tyre pressure. I initially assumed that it may just need recalibrating due to the new tyres bedding in but went to check the pressures and found the nearside rear lower than the other 3 so duly inflated it back up to the same pressure. Two days later the same thing happened so I went to the local Kwik Fit who found a screw embedded in the inside wall of the Bridgestone. In short, perfectly happy with the car for picking this up, gutted at having to fork out £160 for a new tyre in the first week of owning the car.

 

[MrStroppy]

Hi

Quick question, I've got the Leon SC 1.8Tsi dsg on the standard 17" alloys anyone else have the same, if so what pressure's are you running front and back please

 

[FRTSIman]

I have a Leon 5-door FR 1.8TSI DSG with 17" alloys and Bridgestone Turanzas, and run with the SEAT-recommended 32psi at the front and 29psi at the back.

Whenever I finish checking my tyres, I always use the touchscreen menu feature to confirm that the tyre pressures have been set correctly - I thought this was essential for the tyre pressure monitoring system to operate correctly. This procedure is explained in the instruction manual and the correct tyre pressures are also shown on a sticker on the inside of the fuel filler flap.

 

[Mr Pig]

Have you sync'd the tire pressure system after inflating your tyres?

Yes, every time. Perhaps my system is faulty. I'll have to keep an eye on it. Two of the tyres were down around 20psi, which is pretty low.

 

[StevenM]

Me Pig, I'm amazed that you couldn't feel that your tyres were that low. I think the Leon is super sensitive to pressures and feels very different when even a couple of psi down.


Sent from my piece of shite iPhone - according to Muz.

 

[Mr Pig]

Me Pig, I'm amazed that you couldn't feel that your tyres were that low.

That's a fair point. Of course it feels much better now that they are correct but I think there are two reasons I didn't pick up on it. They reduced gradually and I hardly drive the car. The Leon is primarily my wife's car, I can go from one week to the next without driving it, and if something changes gradually you can acclimatise to it and not notice the change.

Yeah, it was a 'duh' moment when I drove the car after correcting the pressures ;0) For years I've been used to doing all my own servicing and checking the car weekly but I've gotten lazy with the Leon.

Incidentally, I usually find the best tyre pressure for any given tyre will be slightly different from the recommended pressure. On the Mazda I found that the Vredestiens felt better and wore more evenly if they were 2psi over. This of course could be totally due to the inaccuracy of the gauge but the point is the same. Set the tyres by the way they behave and the wear pattern, not the gauge.

 

[MrStroppy]

I have a Leon 5-door FR 1.8TSI DSG with 17" alloys and Bridgestone Turanzas, and run with the SEAT-recommended 32psi at the front and 29psi at the back.

Whenever I finish checking my tyres, I always use the touchscreen menu feature to confirm that the tyre pressures have been set correctly - I thought this was essential for the tyre pressure monitoring system to operate correctly. This procedure is explained in the instruction manual and the correct tyre pressures are also shown on a sticker on the inside of the fuel filler flap.

Thanks I'm running 32 front 30 back so happy with that.

 

[Curtly]

What are people with 18's running pressure wise

 

[StevenM]

Agreed Mr Pig, stock pressures as a starting point and adjust to suit tyre brand and personal preference.

Curtly, I'm running stock pressures for my 150 oil burner on 18s - 32 front 29 rear.


Sent from my piece of shite iPhone - according to Muz.

 

[SteveFR]

Noticed that the pothole filled roads around where I live have been giving more of a jolt than normal lately, so thought I'd check my tyre pressures and was surprised to discover that the fronts were down to 28psi and the rears to 24psi

Have inflated them back up to 32/29 (as per fuel flap label) and reset the monitoring system, so hopefully that alerts me next time; for the sake of my poor old bad back!

 

[KXL]

When I had the Leon, my power steering feels heavier with PSI lowered. Once topped up back to recommended levels 32/29, felt lighter again!

Eg...I didn't check my pressure (nor did the car tell me to) when I got it for a good 4-5 months. Must have arrived (I hope) with the correct pressures, checked it at tesco Air pump, rears were 26PSI and fronts were 29PSI, but the pressure did not ping up.

Although when I did have a screw in my rear right a yr later, it did ping up, and surely enough, that suspect tyre was 20PSI!

I wonder what air they put in my Ibiza (from Barcelona). Maybe nitrogen? or super tight air valves. Got it in Dec, and almost 6 months later, it almost hasn't lost any air. Arrived with 38.5 / 36 PSI (Recommended is 38/35 and comfort is 33/30)

I lowered it to 36 / 33 in Dec...checked recently it's still 35.5 / 32.5...PSI, strange..

 

[campbell_p30]

I've a slow puncture on my cupra and if I inflate to 39 psi it pings when it drops to 30 psi.

Sent from my SM-G950F using Tapatalk

 

[concerned cat]

I've a slow puncture on my cupra and if I inflate to 39 psi it pings when it drops to 30 psi.

Sent from my SM-G950F using Tapatalk

I agree. In the past it's been around 10psi drop before it registers a drop in pressure.

 

[MrRilo]

Noticed that the pothole filled roads around where I live have been giving more of a jolt than normal lately, so thought I'd check my tyre pressures and was surprised to discover that the fronts were down to 28psi and the rears to 24psi

Have inflated them back up to 32/29 (as per fuel flap label) and reset the monitoring system, so hopefully that alerts me next time; for the sake of my poor old bad back!

My understanding of the SEAT TPMS is that it is only good for punctures as it is an indirect monitoring system. It uses the ABS sensors to compare the rolling speed of all 4 wheels and should there be a difference in one, it triggers the warning.

If all the tyres are losing pressure over time (as they do), then it wont spot it.

From Google: Indirect TPMS works with your car’s Antilock Braking System’s (ABS) wheel speed sensors. If a tyre’s pressure is low, it will roll at a different wheel speed than the other tires. This information is detected by your car’s computer system, which triggers the dashboard indicator light.

SEAT do not have Direct TPMS which would alert us to all pressures dropping.

From Google: Direct TPMS uses a sensor mounted in the wheel to measure air pressure in each tire. When air pressure drops 25% below the manufacturer’s recommended level, the sensor transmits that information to your car’s computer system and triggers your dashboard indicator light.

 

[oldbutnotwise]

Warning tonight 5 miles into my 17 mile commute home.
Boring slow 5 miles at that, between queuing traffic and 50mph average speed cameras on the M74/M73.

Decided to carry on home at 60mph max, and checked the pressures there.

Had been set at 35psi all round ( on 18's ), and measurements came in at

36psi on both fronts, 35psi on back right, 34.5psi on back left.

Who knows why the warning came on . . .

 

[140 PS SE]

Sorry if this has been done but I just wanted to flag up how poor the tyre pressure monitor is.

The way the system works is actually quite clever, and simple. The expensive way to monitor your tyres is to have sensors inside the tyre which transmit the actual tyre pressure to the car. The Leon doesn't do that!

What the Leon does is look at the numbers coming off the ABS sensors to monitor the rotational speed of each wheel. If a tyre looses pressure the effective diameter of the wheel will get smaller and the wheel will rotate faster for any given road speed. The combluter notices that this wheel is spinning faster than the others and flags up the low pressure in that tyre. Clever, simple and cheap! Basically all that's needed is software in the ECU. The necessary hardware is already fitted to all cars with ABS. Great, except that it's a bit crap!

Well I for one am absolutely delighted to have the ABS based system. Had it on 3 cars now, a Mini, a BMW 118 and the Leon. Its alerted me to nails on the Mini and BMW but in 4 years I have been lucky with the Leon, guess that has jinxed it.

Best bit is when you buy winter wheels. No expensive valves and a press on the calibrate button and all is set. On the wifes Nissan we had to buy 4 expensive special valves but luckily the were self calibrating so no expensive dealer visit.

Give me the ABS system any time.

But you should never rely on the sensors as a substitute for regularly checking the tyres for wear, foreign objects and pressures. They are not a substitute for a good old pressure gauge.