tire pressure monitoring system problems

phillbriggs

Active Member
Dec 15, 2010
79
0
hi there i have a 2007 leon cupra, the car is equipped with the tyre pressure monitoring system, it has the yellow light on the dash when first turning the ignition on and then goes out and also the button in the centre console. you can hold the button and the system will reset with a bleep and then the light goes of on the dash. anyway havnt had the car on the road long at all and had prevously checked my tyre pressures and reset the system, but the next day i noticed my o/s/f tyre was soft about 20psi but i didnt get any warning or signs of this problem whilst driving the car or anything at all which indicates to me that something not working properly???

what pressure does the tyres have to drop to, to get a warning from the system???

where are the pressure sensors on the wheels are they internal on the wheel itself or are they the in the special valves you see on other cars, the valves look like normal rubber valves with no steel sleeve or solid base like you normally see on cars with pressure monitroing, im thinking the sensors or valaves may have been removed when tyres have prevously been fitted, would the system not work if say only 3 valves were present or something???

the other interesting thing is that i have a bosch diag machine at work and went into the car config, the tyre pressure warning option was set to NO???? i reset it to yes thinking this would solve the problem but i then just got a error on the tyre system saying there was no signal or sensor readings, which is why im thinking the sensors are not all present if any????

any ideas or ways of identifing pressure sensors on the wheels is great help???
 

Wellsy

GTI ED35
Feb 8, 2010
135
0
Yorkshire
www.facebook.com
I read in my handbook recently the system uses the ESP system, to measure the rolling circumference of the tyre, so there aren't any specific sensors.

Did you try driving the car with the pressure lower, or did you notice it was low before driving it? I obviously wouldn't advise it if you know you have a low pressure tyre!
 
Jun 5, 2008
511
0
Leeds
As per what Wellsy said there are no tyre pressure monitoring sensors, it goes by the rolling circumference of the wheel. The only time I have seen this sensor come on is when i got my car and the wheel had been upgraded to 18 from 17. Apart from that the light has never come on - pretty useless IMHO
 

Tombstoneuk

Active Member
Mar 5, 2010
170
0
Loughborough
Iv seen the light come on twice now, both with flat tyres. And they were completely flat. It's more of a way of saying u need to stop driving and sort it out now cos there's no air in there. So not totally useless, but close lol.
 

densil

Active Member
Feb 22, 2007
138
0
I had a rear tyre slashed and the thing was flat as a pancake. Unfortunately the system failed to notice it! I was on the M6 within a couple of minutes of driving, a minute later I found myself changing the tyre on the hard shoulder at 11pm, not pleasant! Moral to the story - do not give the tyre pressure monitoring the time of day.
 

SeanCorky

BMW E92 335i M Sport
Sep 4, 2008
809
3
Liverpool
They have been great for me, i had a slow puncture in one of my tyres on my old car. Every couple of weeks it would tell me the pressure was low so i'd top it up and reset the button
 

FR_Flavoured

Guest
They have been great for me, i had a slow puncture in one of my tyres on my old car. Every couple of weeks it would tell me the pressure was low so i'd top it up and reset the button

Same here. On my wifes Leon, the rear offside tyre has a slow pucture.

So every couple of weeks the light comes back on... At which point I take it to a garage and pump it back up - also it DOES take a while on that tyre - so the system was spot on at detecting the problem wheel.

We've also routinely replaced the tyres, as the tread gets low, which hasn't affected the ability of the system to detect a loss of tyre pressure (aka wheel circumference).
 

/dev/null

Active Member
Nov 12, 2008
1,649
101
It takes a while (ie, several miles) for the system to notice that you have a flat - you would probably have noticed yourself by then anyway (especially a front tyre).
 

gh.fr

Leon FR CR TDI
Dec 20, 2007
36
0
Bradford
Mine came on within 2 miles of swapping the wheels front to back. Its got to be pretty clever to notice 3mm fronts being swapped with 6mm rears...
 

SimonFRTDI

Active Member
Oct 13, 2009
122
0
Bristol
As people have said, it is just doing some maths and comparing the set circumference against the currently read one. It worked for me, but again I would not rely on it to let me know about exact pressures.

For those who have changed wheels etc and it has come on - just hold the 'set' button down (engine off) when you have the tyres at correct pressures and it resets the current figure to be the standard.
 

Rua1r1

Rua1r1
May 5, 2009
156
0
Co.Armagh
I'm having problems with mine as well, the light stays on even after I have checked the tyre pressure and reset it etc, don't know what the problem is ? any ideas ? I need to replace the rear driver side wheel bearing and was wondering would that be anything to do with it ?
 
Oct 17, 2006
2,141
0
Mid Wales
Same here. On my wifes Leon, the rear offside tyre has a slow pucture.

So every couple of weeks the light comes back on... At which point I take it to a garage and pump it back up - also it DOES take a while on that tyre - so the system was spot on at detecting the problem wheel.

We've also routinely replaced the tyres, as the tread gets low, which hasn't affected the ability of the system to detect a loss of tyre pressure (aka wheel circumference).

The system works by comparing the rotational speeds of the wheels with each other whilst the car is driving in a straight line - if you have a flat, the circumference of one wheel will alter and so they will spin at different speeds.

The tyres wear reasonably equally (or at least should), so you shouldn't ever get a warning as tyres wear down.

The downside of this system is that if all the tyres lose pressure equally you won't get a tyre pressure warning - for this reason it's important to regularly check the pressures yourself
 

Dean T

Guest
I think it's a great system, always warns me at the right time, thought it was a bit of a gimmick at first but I like it :)
 
Aug 16, 2007
666
0
Wolverhampton
I've had the light come on when swapping front-to-rear and not had it when the one of the fronts had a hole in it the size of a 50p. Just my experiences.

As it works off the ABS then it's a cheap system to 'fit' - better than not having it at all.
 

OLDOILER

Full Member
Jul 28, 2005
1,292
1
Wiltshire, UK
I'm having problems with mine as well, the light stays on even after I have checked the tyre pressure and reset it etc, don't know what the problem is ? any ideas ? I need to replace the rear driver side wheel bearing and was wondering would that be anything to do with it ?
The magnetic pickup is built into the hub, if the bearing is has bad as you say then this could throw the reading sent to the ABS unit - just a thought ?
 

begbie

Newbie
Sep 4, 2006
78
0
The magnetic pickup is built into the hub, if the bearing is has bad as you say then this could throw the reading sent to the ABS unit - just a thought ?

Could you direct me to where this magnetic pickup is? I know you say that it's on the hub, I assume you mean the hub of the wheel? :confused: I've just had this same problem occuring this morning!
 
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