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Oh dear....horseshoe yellow light stays on - TPM


twoladies

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....so off I went to the Skoda dealer down the road from me.  The service guy said the tyres look OK and he reset it and showed me how.  20 miles on, not come on again.  He said that if you hit a pothole this can cause it.  They were very pleasant as I said they will be doing my annual servicing.  I suppose, because of the VW problem, they appreciate customers.

 

Will check all the tyre pressures again when its not so cold! :D :D Hopefully, not a slow puncture.

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My Yeti is about 16 months old and it's happened twice to me for no discernible reason. I also just reset the tpm. I wonder how common this is?

Edited by longedge
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Once it has been reset, it takes about 100 miles for it to register the new settings. Only after that will it become properly active.

I've hit quite a few potholes and not had TPMS come on! It only comes in if the rotational speed registered by the ABS sensor register a difference from what it has been set to.

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re post #4,

Where does this 100 miles before they register the new setting stuff come from?

 

Something I picked up on this forum that kind of made sense since the system works off the ABS sensors which won't know the rotating speed until the tyres have started moving.

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KBphoto,  

100 miles before the ABS knows the rotating speed and the circumference of the tyre has changed.

That is just nonsense really.

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KBphoto,  

100 miles before the ABS knows the rotating speed and the circumference of the tyre has changed.

That is just nonsense really.

It would take an awfully long time to get an average discrepancy when lots of town turns are involved prior to a significant run frinstance.
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KBphoto,  

100 miles before the ABS knows the rotating speed and the circumference of the tyre has changed.

That is just nonsense really.

You are entitled to your opinion - I have no concrete proof either way.

 

However, the explanations I have heard to back this up make sense to me - But I'm not an engineer! - and Ryeman is seems to say what I have heard elsewhere.

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It just makes sense trillions of bytes to detect a minor variation after initialising would be needed to eliminate the manoeuvring variations of axle rotation.

Edited by Ryeman
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It should calibrate within 20 minutes of driving but can take hours depending on road conditions to fully calibrate.

Lots more info here: http://www.my-gti.com/321/volkswagen-tyre-pressure-monitoring-system-tpms

I changed from indirect to direct tpms to give quicker warning about both slow and quick pressure losses :-)

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I guess if you circumnavigate London on the M25 you're going to get a rotational difference between NS v OS wheels and should therefore get a warning.......or not?.

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From what I remember from my Yeti's handbook, the system works by monitoring the rolling profile of the tyres. Again, IIRC, there was no mention of the ABS being involved.

I believe I proved this when I overloaded the car with wood and the TPMS alarmed. When I checked the pressures after unloading it, they were all correct

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Does this shed any light ?

 

In the interest of providing a lower cost Original Equipment system, indirect tyre pressure monitoring systems were developed by vehicle manufacturers wishing to comply with the law while minimizing development time and cost. Indirect systems use the vehicle's antilock braking system's wheel speed sensors to compare the rotational speed of one tyre to that in another position on the vehicle. If one tyre is low on pressure, its circumference changes enough to roll at a slightly different number of revolutions per mile than the other three tyres. Reading the same signal used to support ABS systems, the vehicle manufacturers have programmed another function into the vehicle's onboard computer to warn the driver when a single tyre is running at a reduced inflation pressure compared to the others.

 

Unfortunately, indirect tyre pressure monitoring systems have several shortcomings. Indirect systems won't tell the drivers which tyre is low on pressure, and won't warn the driver if all four tyres are losing pressure at the same rate (as occurs during the fall and winter months when ambient temperatures get colder). Additionally, our current experience with indirect systems indicates that they can generate frequent false warnings. We have found that false warnings may occur when the tyres spin on wet, icy and snow-covered roads. In these cases, the false alarms would train the driver to disregard the tyre pressure monitoring system's warnings, negating its purpose completely.

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?

How do you think the Brain 'Monitors the rolling profile of the tyres'  Mind over matter, or maybe with the ABS Sensors?

Why ask me - try Skoda it was their vehicle and their handbook. You obviously know more than them!

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The TPM may be an imperfect system but twice mine has alerted me to low pressure in one of the tyres and I've found a nail sticking out of the tread withd the resultant slow puncture. I'd not felt anything unusual through the steering and the second time (a couple of weeks ago) when the alarm went off I pulled in to the side of the road and walked round the car for a quick visual inspection and couldn't see anything obvious amiss. I'm afraid I'm not one of those people that religiously checks tyre pressures once a week or more so for me because of the early warning the TPM gave it may have been saved me the cost of a new tyre on both occasions.

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Old habits die hard, especially those established over 30 years driving at work. I still start any significant journey with a vehicle check - Oil, coolant and wiper fluid levels then tyres for pressure and damage. A quick trip to the shops and I walk round and do a visual check before getting in the car. I don't claim to be able to spot the loss of a couple of pounds in tyre pressure but between the visual check, changes in handling and the weekly (or thereabouts) check with my gauge I reckon that I could very well manage without this bit of flaky technology. 

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When set 40,000 miles ago, have the tyres pressures always been the same, never increased or decreased, and you have never checked the system or reset it when checking the tyre pressures from season to season?

 

If the car has been serviced, the Technician might have checked or adjusted the tyre pressures and Checked and Reset the TPMS, unless you know that was never done.

Edited by GoneOffskiroottoot
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On Tuesday my TPM alerted me to a problem. I immediately pulled in case I had a flat. Saw nothing but checked pressures and yes my nearside back tyre was quite low on pressure. Pumped it up and I'm now checking daily but cannot discern any daily drop. Will continue to do this till I take the winter tyres off - sooner it it deteriorates - and then take that wheel/tyre to tyre fitters for thorough check. This is the third time in 4 years that my TPM has given me useful valid info and never had any false alarms. Would not like to be without it now.

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Will continue to do this till I take the winter tyres off...

I'd suggest tracking down any slow puncture a.s.a.p. - it could save the cost of a new tyre or worst case a blowout and accident.

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