Question on tyre pressure monitoring system

[azibux1]

Hi all

So the S3 doesn't have proper TPMS that can give exact value of PSI, instead it is ABS sensor / rolling resistance related

My question is when should you then click the store pressures button on the MMI?

Because clicking it at a standstill is surely a bit useless as there is no rolling resistance and the ABS sensor isn't doing much? But on the other hand clicking it after driving for a while, the tyres will be hot, so higher pressures... Meaning probably everytime you start the car after leaving it overnight, you'll probably get a lower pressure warning as they will have cooled down?

I know this abs sensor / rolling resistance TPMS isn't great anyway, but I'd like to try and get the best use out of it

What are your thoughts?

Thanks!

 

[RichardT]

My understanding is that it is basically measuring the difference between the speeds on each wheel.
Resetting in the MMI just normalises the settings. You’re telling the car that the pressures are correct and it takes that as normal (even if the speeds are slightly different - eg different depths of tread)
So it doesn't really matter if you reset when the your stationary or moving, or hot or cold.

 

[Flying Scotsman]

That is correct.
Temperature has no affect...hot or cold

The tire pressure monitoring system looks at the ABS wheel speed sensors and uses that information to track the rotational speed of the tires. Any time a tire has lower pressure, it will roll at a different number of revolutions per mile than tires that have the correct tire pressure. If one tire’s rotational speed seems off compared to the rest, the TPMS will alert the driver that one of the tires has low pressure.

 

[pburv]

As Richard and FS say...
You can have the tyres set really low and still set the tyre pressure monitor.

 

[azibux1]

Thanks for the explanations and sorry if I'm misunderstanding something simple here... but should it be done then whilst moving?

Example... 40 PSI in all tyres (not true, just an example), standstill, store the pressures in the MMI and then let 10 PSI out of 1 tyre and begin to drive off... the system won't know how many rotations they were doing whilst 'normal' as the car was at a standstill when it was stored? And therefore won't know that one is missing 10 PSI?

 

[RichardT]

Thanks for the explanations and sorry if I'm misunderstanding something simple here... but should it be done then whilst moving?

Example... 40 PSI in all tyres (not true, just an example), standstill, store the pressures in the MMI and then let 10 PSI out of 1 tyre and begin to drive off... the system won't know how many rotations they were doing whilst 'normal' as the car was at a standstill when it was stored? And therefore won't know that one is missing 10 PSI?

To start with, you don't "store the pressures" as such. But I think that, in your example, the system would not alert you to the low pressure - based on the explanations above.

 

[mikemod]

Once you press the reset, the system then learns the new values over the next few miles and uses those as a reference.

 

[azibux1]

To start with, you don't "store the pressures" as such. But I think that, in your example, the system would not alert you to the low pressure - based on the explanations above.

Correct, I was just basing it off the terminology used on the MMI screen (as best as I can remember)

Sounds like it is best to hit the MMI option then whilst driving rather than whilst at a standstill

 

[azibux1]

Once you press the reset, the system then learns the new values over the next few miles and uses those as a reference.

That's great then! Thanks

 

[TYb]

That's great then! Thanks

If it's the same system in the TT you can only set them when stationary. Best to set them immediately after pumping them up, then that is your baseline, the system will pick up changes there on.

 

[Wibbly]

After I set the pressures and TPMS in the summer, I have only recently remembered to check them (trusting TPMS). Pressures were WAY down on ALL the tyres (I presume due to lower ambient temperatures now). Point is, I think TPMS is looking for differences between the wheels. So if they all change their rolling circumference at the same time (like when they all lose pressure at the same time or perhaps even if you get 4 punctures at the same time (!)) it won't alert you it seems... This kind of makes sense insofar as then TPMS wouldn't be triggered as you speed up, tyre temperatures change (evenly) when driving, etc.

There are some aftermarket tyre pressure monitors that measure absolute pressure, but that's off thread here

 

[azibux1]

Yeah it seems it is very important to note that what you've experienced. It won't tell if they all become low pressure over time which is a bit rubbish but just a limitation of the system I guess.

Would be nice if it had proper TPMS

 

[Wibbly]

OK, I have used this (but not so far on my Audi - may give it a go now)
http://www.tyrepal.co.uk/products/tb99-4-or-5-wheel-tpms

Worked fine on my Focus, and I felt the effect on wheel balance was not enough to worry about. Not enough to worry about having the wheels rebalanced with the sensors fitted, anyway.

 

[Aparatos]

Correct, I was just basing it off the terminology used on the MMI screen (as best as I can remember)

Sounds like it is best to hit the MMI option then whilst driving rather than whilst at a standstill

You cant set/reset it while driving you have to stop for the option to come up.

 

[azibux1]

OK, I have used this (but not so far on my Audi - may give it a go now)
http://www.tyrepal.co.uk/products/tb99-4-or-5-wheel-tpms

Worked fine on my Focus, and I felt the effect on wheel balance was not enough to worry about. Not enough to worry about having the wheels rebalanced with the sensors fitted, anyway.

Thanks might check it out!

 

[Daveotto]

1. Pump up tyres to correct value
2. Reset TPMS in the MMI
3. Drive at steady speed for 10 mins*or so at no more than 50mph* so the TPMS software algorithm can set the correct rotational speed for each wheel

*the exact time and speed are somewhere in the manual, which no one (including me) can be bothered to read

P.S sure there is a thread or two or something in the FAQ as well on same subject

P.P.S based on experience the A3 TPMS is able to detect a drop in 2-3 psi in one tyre

 

[Wibbly]

3. Drive at steady speed for 10 mins*or so at no more than 50mph* so the TPMS software algorithm can set the correct rotational speed for each wheel

*the exact time and speed are somewhere in the manual, which no one (including me) can be bothered to read

I bothered. Could find nothing about this in my manual.

 

[Daveotto]

I bothered. Could find nothing about this in my manual.

Must admit to not reading my S3 manual, I might have seen it in the manual from my 8p A3 as was around the time TPMS became compulsory (I think!!!)

 

[deanshaw24]

This type of TPMS isn't very accurate either.. I think a tyre needs to drop by around 10-15psi before it notices.

 

[azibux1]

1. Pump up tyres to correct value
2. Reset TPMS in the MMI
3. Drive at steady speed for 10 mins*or so at no more than 50mph* so the TPMS software algorithm can set the correct rotational speed for each wheel

*the exact time and speed are somewhere in the manual, which no one (including me) can be bothered to read

P.S sure there is a thread or two or something in the FAQ as well on same subject

P.P.S based on experience the A3 TPMS is able to detect a drop in 2-3 psi in one tyre

Thanks! Quite detailed info. Shame on the speed limit

 

[Daveotto]

This type of TPMS isn't very accurate either.. I think a tyre needs to drop by around 10-15psi before it notices.

You think wrong ... my experience, see my post above, is that it will detect a 2-3 psi drop in one tyre.

A system that only detected a drop of 10 -15psi would be a bit of chocolate teapot as you would notice it yourself e.g steering would pull at that differential.

The problem with the A3 TPMS is that is does not detect a drop on pressures across both tyres on one axle, through either incorrect inflation or air loss over time.

Recently, my S3 sat on the drive for best part of 2 months and tyres not checked for about 3 months and all 4 tyres dropped about 3-4 psi but TPMS did not trigger

 

[deanshaw24]

You think wrong ... my experience, see my post above, is that it will detect a 2-3 psi drop in one tyre.

A system that only detected a drop of 10 -15psi would be a bit of chocolate teapot as you would notice it yourself e.g steering would pull at that differential.

The problem with the A3 TPMS is that is does not detect a drop on pressures across both tyres on one axle, through either incorrect inflation or air loss over time.

Recently, my S3 sat on the drive for best part of 2 months and tyres not checked for about 3 months and all 4 tyres dropped about 3-4 psi but TPMS did not trigger

But surely a 2psi drop would make absolutely no difference to rolling radius?

 

[larbel]

It will go off as long as there's noticeable tire speed difference. Mine went off when there was a 4 psi drop at the rear right tire couple months ago. I'm ok with the system, as I usually check tire pressures when getting gas every other week or so. But if you're really worried, there is 2nd gen TPMS kit from VW/Audi that can be had for about US$250? And will display on MMI when activated with VCDS.

 

[Daveotto]

But surely a 2psi drop would make absolutely no difference to rolling radius?

It obviously makes a difference to rolling radius or whatever else the system monitors to allow it to trigger....if GPS can detect a distance of 1 metre from a height of several miles its not to much to believe VAG can't detect a difference of a few millimetres circumference per revolution of a wheel with a diameter of around 2.5M

 

[DJAlix]

It will go off as long as there's noticeable tire speed difference. Mine went off when there was a 4 psi drop at the rear right tire couple months ago. I'm ok with the system, as I usually check tire pressures when getting gas every other week or so. But if you're really worried, there is 2nd gen TPMS kit from VW/Audi that can be had for about US$250? And will display on MMI when activated with VCDS.

View attachment 113802 View attachment 113803

Got a link to this kit by chance? I have all the bits bar the wiring but knowing where to source the complete kit would be useful

 

[larbel]

Got a link to this kit by chance? I have all the bits bar the wiring but knowing where to source the complete kit would be useful

Most of the shops in China carries them, but here's a Aliexpress guy selling for $325 https://www.aliexpress.com/item/Vol..._4&btsid=166f6670-0c06-427e-9d43-802a544e68e3

 

[DJAlix]

Most of the shops in China carries them, but here's a Aliexpress guy selling for $325 https://www.aliexpress.com/item/Vol..._4&btsid=166f6670-0c06-427e-9d43-802a544e68e3

Thanks

 

[JDHOWELLS]

Where do you find the reset option in the mmi?


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[Tom.H]

Where do you find the reset option in the mmi?


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This should help

https://www.paradigital.net/8vfl/ba/page_00732.htm

 

[Rcord]

It will go off as long as there's noticeable tire speed difference. Mine went off when there was a 4 psi drop at the rear right tire couple months ago. I'm ok with the system, as I usually check tire pressures when getting gas every other week or so. But if you're really worried, there is 2nd gen TPMS kit from VW/Audi that can be had for about US$250? And will display on MMI when activated with VCDS.

Looks like a cool retrofit to do. Indirect TPMS never worked for me. A couple weeks ago I had two flat tires after hitting a pothole and TPMS only warned me that there was something wrong the next day, after I had already replaced both tires.
I've looked for the parts for a direct TPMS kit but Chinese sellers won't supply any information about installation and coding and Audi electrical diagrams don't even include that feature for A3. Pictures show TPMS on an A3 MMI screen so it seems that it's supposed to work, but did anyone sucessfully retrofitted a TPMS kit on the A3?

 

[larbel]

I just did the retrofit myself, my supplier was able to give me a great deal that I couldn't resist lol The module is fixed to the inside of the rear bumper and running wires to the fuse box for power, took me like 2 hours. Now just need to go to tire shop and have them fit the sensors and then do the coding then it's all set. Something I wanted to do for a while now since I have retrofit VC and MMI2 in my PFL..

 

[Rcord]

I just did the retrofit myself, my supplier was able to give me a great deal that I couldn't resist lol The module is fixed to the inside of the rear bumper and running wires to the fuse box for power, took me like 2 hours. Now just need to go to tire shop and have them fit the sensors and then do the coding then it's all set. Something I wanted to do for a while now since I have retrofit VC and MMI2 in my PFL..

That's great! What part numbers did you use for the module and sensors? And about the CAN High and CAN Low signals what connection points did you use? I've found a detailed tutorial on how to install TPMS (in Spanish, with some pictures of German and Russian manuals too), but the cars shown are a Seat and a Golf VII and they seem to connect CAN wires to different points.
http://www.areavag.com/foro/showthr...ar-control-presion-de-neumaticos-directo-TMPS

 

[larbel]

That's great! What part numbers did you use for the module and sensors? And about the CAN High and CAN Low signals what connection points did you use? I've found a detailed tutorial on how to install TPMS (in Spanish, with some pictures of German and Russian manuals too), but the cars shown are a Seat and a Golf VII and they seem to connect CAN wires to different points.
http://www.areavag.com/foro/showthr...ar-control-presion-de-neumaticos-directo-TMPS

I ordered mine with the VIN and didn't really check part numbers... It came with plug n play connector to the Gateway, and all you need is run a wire to fuse power and ground...

 

[Rcord]

I ordered mine with the VIN and didn't really check part numbers... It came with plug n play connector to the Gateway, and all you need is run a wire to fuse power and ground...

Fine. Looks better than looking for parts from separate sellers. Would you please post a link for your supplier?

 

[larbel]

Fine. Looks better than looking for parts from separate sellers. Would you please post a link for your supplier?

Err.. Can't really, they're in China.. Mine's like GBP 220 but there's guy selling them on Aliexpress...

 

[larbel]

Finally got around to have the sensors fitted and did the coding It's actually much more useful than I thought and displays nicely on the VC

 

[oli356]

Wouldn't mind direct TPMS (or whatever its called), I don't understand why the A3 doesn't as standard... cars half the price come with it ***.

I check mine, somewhat regularly, especially before long journeys but shouldn't even have to. What Audis come with this as standard then?

 

[Rcord]

Finally got around to have the sensors fitted and did the coding It's actually much more useful than I thought and displays nicely on the VC

View attachment 156126 View attachment 156127

Looks great on the VC! I'm still trying to check if it will work with the model of MMI I have in my A3 before proceeding to the retrofit. What about the pressure units? Do you know if it's possible to display it in PSI instead of BAR? (measurements in BAR are meaningless for me!).

 

[jrumball]

Just ordered all the parts to add direct TPMS to my car. Found a receiver for £30 on as saved search and then the harness and 4x sender for about £80 so £110 all in very reasonable. The only thing I'm having trouble with is the bracket for the receiver, I can't find it in the parts catalogue any where does anyone have a location and part no. for it please .

 

[Svenedin]

Very nice but an extra problem (and expense) when changing a tyre.