TPMS sensors mass suicide..?

[Iain_S4]

I've just ordered a new antenna. How does the antenna release from the bracket/holder - had a quick look a few weeks ago but to my shame didn't figure it out then. Its easier to ask than fiddle with it for ages.

[pisquano]

If the system is active i.e. you can access setting via the DIS then the sensors will be working.
To test, after a longish drive, keep engine running and deflate a tyre.

ok so I have a potentially stupid question
if the system is triggered only after a longish drive, then the actually pressure measured of the tyres won't necessarily be accurate 100% isn't it? audi recommends to inflate the tyres at ambient temperature, or you can get wrong levels.
but then, does the system compare the stored levels to the "measured" levels, adjusting the latter to the fact that at that stage the tyres are warm hence there is a difference factor to be removed?
not sure If I made myself clear

[bam_bam]

The TPMS only warn of a drop in pressure. If the tyres pressures are stored when hot, then when the car cools there will be a warning, ne?

[pisquano]

that's why I ask. if stored pressures are with cold tyres, then TPMS compares those to pressures in hot tyres? (higher pressure than real)

[almoRS]

I've just ordered a new antenna. How does the antenna release from the bracket/holder - had a quick look a few weeks ago but to my shame didn't figure it out then. Its easier to ask than fiddle with it for ages.

Once you pop-out the honeycomb grill just pull the antenna out of the bracket on the cable, then fix the same one back in. It is a single plugged cable.

[bam_bam]

that's why I ask. if stored pressures are with cold tyres, then TPMS compares those to pressures in hot tyres? (higher pressure than real)

I don't understand your point. TPMS is a simple IF THEN statement i.e. IF tyre pressure is lower than stored pressure THEN warning. It doesn't care about temperatures.
The reason Audi ask you to store pressures when 'cold' is this will be the lowest acceptable pressure, a baseline if you will. If pressures were stored when hot then when the tyres have cooled, there will be less pressure, hence a warning.
It is an extremely simple system, it's not rocket surgery.

[pisquano]

my point is that if you compare an pressure value of a hot tyre (increased temporarily) with a value when cold (accurate) the comparison is unprecise by definition because of the temporary increase in pressure when running.

but yea, once the tyres have become "cold" again the TPMS will trigger its warning there and then if the value is lower.

anyway there a few things that could go wrong with TPMS: my question is whether VAGcomm can detect each of them: (1) battery out (2) broken sensor (3) broken antenna (4) any combination of 1,2 and 3

[neckarsulm]

You don't need Vag Com to detect those faults, if any of them occurs, a message is posted in the DIS to that effect.
Trying to deduce which problem has caused the fault message does require VCDS.

As for temp readings, surely VCDS cross references temp with pressure so it can tell sooner if there is pressure loss?
e.g. a 4 PSI pressure loss at the same temp could be read as a 2 PSI loss with an increase in temperature of x

[pisquano]

OK I see.... but then again I need to do some more testing as the system didn't warn me although I had a tyre less than 3bar minus the stored value

[Iain_S4]

Ok, new antenna fitted but still have TPMS fault message in the DIS .Stored tyre pressures, took car for a drive etc to no avail. Do you need Vagcom to clear the fault message?

[neckarsulm]

Iain,

I don't think you need to clear the fault with VCDS as it should check it on start ip.
Did you check with the VCDS that the fault was actually the antenna?

Does the fault come on as soon as you turn the ignition on?
On the last car I changed the aerial it didn't fix the problem and my next suggestion would have been new sensors and then TPMS ecu which others have had to change.

[Brooner]

Just repaced my antenna but when i removed the rear mesh a metal clip came out and i can't see were it goes anyone any ideas were it should be clipped

[Iain_S4]

Just repaced my antenna but when i removed the rear mesh a metal clip came out and i can't see were it goes anyone any ideas were it should be clipped

That happened to me to - couldn't manage to figure out where it came from but kept it somewhere. The panel seems to stay in ok without it. If anybody has it figured out please let us know.

Did you check with the VCDS that the fault was actually the antenna?

No, I didn't have access to VCDS so didn't check. The fault originated when the car was running its winter wheels and as I didn't know how old they were thought a battery might have gone in the wheel sensors. However, it was suggested that the TPMS fault message in the DIS meant it was more serious. When the summer wheels were put back on the fault persisted so without access to VCDS hoped it was the antenna and changed it.

[Brooner]

Ian
i have Vagcom i can run a test if you like pm me if you would like me to run a test

[Brooner]

Got this while trawling the net as my TPMS is still going off after changing the antenna audi had a look and shock horror "sorry sir cant see any thing wrong we have reset the settings so keep an eye on it" fecking fitters there useless are there no mechanics anymore so now it's either all the sensors battery life ruuning out after 4 years or the controler module so i decided to disable the sensors for now untill i change my tyres and then i will replace all 4 sensors so here how to disable the TPMS
select 17 Instuments then adaption Channel then enter 61 now what ever value is there subtract 512 and that should disable the TPMS i will let you know if it stays off as i just did it tonight