Spurious TPMS warnings

[Kestrel]

I took delivery of my new car on Sep 1st and since then I have had 6 or 7 spurious TPMS warnings.

Now, I am a very low mileage / local driver and during these local trips (10 to 20 miles) I have no problems at all.

But as soon as I take a longer drive (40 or 50 miles) I always get a TPMS warning.

I had the car back to the dealer last month to check it out. They kept the car overnight but couldn’t replicate the issue. They said they made some `adjustments` and hoped it would now be okay. (Whilst in their care they destroyed my precious average MPG…but that’s a different story).

Since they made the adjustments I have only done local drives with no probs…until yesterday when I went down to Peterborough (40 miles or so) and guess what…yeah another warning. As always I check the pressures and they are all okay.

I’ll contact the dealer again but in the meantime, do any of you chaps have any ideas?

Many thanks.

 

[cuke2u]

As they work from the abs sensors is there anything that could be interfering with them? Mud or snow could...

 

[Kestrel]

As they work from the abs sensors is there anything that could be interfering with them? Mud or snow could...

Thanks for your response.
No, I dont think so, we've had no snow and I keep my car well detailed.
It'll be interesting to hear what the dealer has to say!

 

[maui]

Hopefully not tyre dressing on the tread!

 

[S.line]

When it comes up are you losing any pressure? Also do you have the correct valves (I think from memory audi valve caps come in two different types, tpms and non tpms)


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[Kestrel]

When it comes up are you losing any pressure? Also do you have the correct valves (I think from memory audi valve caps come in two different types, tpms and non tpms)


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As I said in my OP. each time its happened I've checked the pressures and all have been as they should.
A few years back I had a Chrysler 300C which had special valves because each tyre gave a pressure readout on the dash.
My Audi valves look just like any other, as do the caps.

 

[cuke2u]

It'll be the version that uses ABS to sense the rotational speed variations not the ones that have wireless tpms valves https://www.national.co.uk/information/tpms-sensor-valve-service-and-replacement

 

[Retroman]

Chucking some ideas in:- Is the gauge on the pump you are using accurate? Any chance you have a slow puncture/leak? Any chance they have been filled with different gases which are expanding/contacting at a differing rate - longer drive = more tyre heat? - replication at a garage would require them to simulate a longer drive. Do you keep any electrical equipment or chargers etc in the car which you would have removed when leaving the car at the garage?

 

[Kestrel]

Chucking some ideas in:- Is the gauge on the pump you are using accurate? Any chance you have a slow puncture/leak? Any chance they have been filled with different gases which are expanding/contacting at a differing rate - longer drive = more tyre heat? - replication at a garage would require them to simulate a longer drive. Do you keep any electrical equipment or chargers etc in the car which you would have removed when leaving the car at the garage?

Thank you, `Retroman` for your ideas.

Let me try to explain whats happening:
I pump the tyres up to the correct temperatures (36 front, 33 rear) today.
I drive around locally for a week or so.
I then take a longer drive and get the TPMS warning.
I leave the car overnight to make sure the tyres are cold.
The next day I take the pressures and the are exactly the same (36 front, 33 rear).

I have already thought that `heat` on a longer drive may be a factor here and will be mentioning that to the dealer.

Thanks again.

 

[desertstorm]

The car uses the ABS sensors to monitor wheel speed to determine if a tyre has gone flat. When a tyre loses pressure it's circumference reduces so it rotates fractionally faster. This is the mechanism it uses to determine there is an issue. When you blow the tyres up to the correct pressures and hit the reset button the next time you take the car for a run it monitors the various rotational speeds of the tyres to set a reference point.
When going on a longer trip the tyre is more likely to heat up and pressure increase. This should be similar front and rear so the relative speeds of the tyres will be the same.
However I suspect that one end of the car is having a greater increase in pressure and this is causing an issue. The best thing to do is measure tyre pressures at the start of the journey and then as soon as possible after the TPMS has said there is an issue. You should have a similar pressure rise in all tyres.
The starting pressures you have look a little low to me, I use the fully loaded tyre pressures at all times on my car. It says in the manual this is the best for fuel economy etc .
Are they tyres directional? Are they all fitted correctly with the tyre rotation correct. If the geometry / tracking is incorrect this could result in more heat being generated in a tyre that would result in it's pressure increasing more.
I think the key to sorting this is spotting the relative change in pressures on a longer trip and then going from there to see why the issue is occurring.

 

[cuke2u]

I also set mine on cold tytres to the same pressures and I also mostly drive around town, did not have any TPMS warnings though when I went on a 350 round trip over Christmas. That also included some more 'spirited' driving.

 

[gbrown]

Thank you, `Retroman` for your ideas.

Let me try to explain whats happening:
I pump the tyres up to the correct temperatures (36 front, 33 rear) today.
I drive around locally for a week or so.
I then take a longer drive and get the TPMS warning.
I leave the car overnight to make sure the tyres are cold.
The next day I take the pressures and the are exactly the same (36 front, 33 rear).

I have already thought that `heat` on a longer drive may be a factor here and will be mentioning that to the dealer.

Thanks again.

Did you reset the TPMS after adjusting the tyre pressures?

Geoff

 

[Kestrel]

Did you reset the TPMS after adjusting the tyre pressures?

Geoff

Oh yes. After each of the spurious warnings and after my fortnightly pressure checks.

 

[PR.]

I assume it doesn't tell you which wheel it thinks is causing a problem?

I would have thought the dealers could pull the logs of which wheel is reporting an issue and if it happens again against the same wheel it would indicate a faulty sensor which they can replace?

 

[cuke2u]

I would have thought though that if a ABS sensor was faulty in any way an ABS error would also come up. It could be the TPMS module of course...

 

[Kestrel]

I assume it doesn't tell you which wheel it thinks is causing a problem?

I would have thought the dealers could pull the logs of which wheel is reporting an issue and if it happens again against the same wheel it would indicate a faulty sensor which they can replace?

No, no indication of the `offending` tyre. It just says to check `em all!

 

[gbrown]

In the order tracker for my S4 it lists "Direct tire pressure monitoring system" which implies that at least for my specification it is using direct measurements of the tyre pressures, rather than relying on the relative rotation speeds. I've tried to Google this, but haven't yet got any solid indication whether this is standard for all Audi's, S4, A4 or otherwise. However, it seems most likely that all A4's use Direct TPMS (rather than indirect). Perhaps someone with the full order breakdown via the tracker for an A4 could look to see if they have the same XML section as my S4?

{
"subParentLabel": "RDK",
"productId": "MRDK7K1",
"name": "Direct tire pressure monitoring system",
"displayable": true,
"standard": false
}

N.B. Everything listed in my order has "standard": false, so no idea

If the cars are using Direct TPMS, then the warming would be due to one or more sensors reporting a low pressure (I understand this is likely to be below around 28 psi) rather than a rotational difference, which could be caused by uneven changes in pressure. Since the pressure are all well above what could be considered low after the warning has been seen, it seems most likely that at least one sensor is faulty, or something is causing a problem in the sensors communicating with the TPMS receiver.

As PR. says, this should show in the log!

Worth asking the technician to confirm if the TPMS is Direct (as stated in the order XML) or Indirect, and what the logs show.

I found a little info here... http://www.eurocarservice.com/audi/119220

"Sensors within the tire, or on the car, send information to one or several modules in the car. These modules are programmed with a range of acceptable circumstances. For direct tire pressure monitoring, this is often between 28 and 35 pounds per square inch (psi) of air in the tire."

Geoff

 

[Kestrel]

In the order tracker for my S4 it lists "Direct tire pressure monitoring system" which implies that at least for my specification it is using direct measurements of the tyre pressures, rather than relying on the relative rotation speeds. I've tried to Google this, but haven't yet got any solid indication whether this is standard for all Audi's, S4, A4 or otherwise. However, it seems most likely that all A4's use Direct TPMS (rather than indirect). Perhaps someone with the full order breakdown via the tracker for an A4 could look to see if they have the same XML section as my S4?

{
"subParentLabel": "RDK",
"productId": "MRDK7K1",
"name": "Direct tire pressure monitoring system",
"displayable": true,
"standard": false
}

N.B. Everything listed in my order has "standard": false, so no idea

If the cars are using Direct TPMS, then the warming would be due to one or more sensors reporting a low pressure (I understand this is likely to be below around 28 psi) rather than a rotational difference, which could be caused by uneven changes in pressure. Since the pressure are all well above what could be considered low after the warning has been seen, it seems most likely that at least one sensor is faulty, or something is causing a problem in the sensors communicating with the TPMS receiver.

As PR. says, this should show in the log!

Worth asking the technician to confirm if the TPMS is Direct (as stated in the order XML) or Indirect, and what the logs show.

I found a little info here... http://www.eurocarservice.com/audi/119220

"Sensors within the tire, or on the car, send information to one or several modules in the car. These modules are programmed with a range of acceptable circumstances. For direct tire pressure monitoring, this is often between 28 and 35 pounds per square inch (psi) of air in the tire."

Geoff

Being as you are spelling tyre as `tire`, does that mean you are not in the UK? If so, things might be different where you are.

 

[gbrown]

Being as you are spelling tyre as `tire`, does that mean you are not in the UK? If so, things might be different where you are.

I am in the UK, I was just quoting the order tracker, which spells tyre as tire! I always spell it correctly...

 

[Kestrel]

I am in the UK, I was just quoting the order tracker, which spells tyre as tire! I always spell it correctly...

Thank you for your help, `gbrown`.

 

[gbrown]

Thank you for your help, `gbrown`.

This is what it says in the online/MMI manual

"The tyre pressure loss indicator makes use of the ABS sensors to compare the rolling circumference and the vibration of the tyres. If changes in the inflation pressure are detected on one or more tyres, the driver is alerted by an indicator lamp

and a message in the instrument cluster display. If only one tyre is affected, the display will indicate its position.
Each time you change a tyre, change the wheels round or change the tyre pressures on your vehicle (e.g. when switching from partial load to full load and vice-versa), you must store the new tyre pressures on the infotainment system link►. Monitoring of the tyre pressures is based on the tyre pressures you have stored. The inflation pressures recommended for your vehicle are given on the tyre pressure sticker Fig. ►.
The rolling circumference and vibration can change and cause a tyre pressure warning if:

• The inflation pressure in one or more tyres is too low.
• The tyres have suffered structural damage.
• The wheels were changed or the tyre pressures were changed and the new tyre pressures were not stored link►.
• Only some of the worn tyres have been replaced."

This describes Indirect TPMS, so I suspect the order tracker is telling lies and the TPMS does just rely on the ABS sensors, which is a shame, as these have proven error prone compared to Direct TPMS on previous cars.

Geoff

 

[cuke2u]

Definately the tyre pressures are read from the abs sensors as there are no sensors in the valves..

 

[desertstorm]

Direct TPMS is a much better way of monitoring tyre pressure as it reads the actual pressure in each tyre . Doing it via the ABS sensors really costs nothing extra to the manufacturer as all the hardware is already present, it's just a bit of extra software to monitor the ABS wheel speeds and try and calculate whether there is an issue.

 

[DeanoC]

Are you sure it is done via the abs sensor? My B8.5 has sensors in the wheels. Common faults are when they are installed wrong or the bluetooth gets interference.

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[desertstorm]

Does your car display the individual tyre pressure and temperature on the display ? Pretty much only the top line RS cars, S8 , R8 etc get direct TPMS systems these days.

 

[DeanoC]

Does your car display the individual tyre pressure and temperature on the display ? Pretty much only the top line RS cars, S8 , R8 etc get direct TPMS systems these days.

Oh i see. I just thought if i had it everything newer would.

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[cuke2u]

Are you sure it is done via the abs sensor? My B8.5 has sensors in the wheels. Common faults are when they are installed wrong or the bluetooth gets interference.

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As the manual clearly states the monitoring system uses the abs sensor which part are you not understanding?

 

[DeanoC]

As the manual clearly states the monitoring system uses the abs sensor which part are you not understanding?

Yea my bad. I didn't read a B9 manual as i don't have one.

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[cuke2u]

Fair enough if you don't have access to this information...

 

[DeanoC]

Fair enough if you don't have access to this information...

I did the classic web forum thing of read the first couple of pages where there was debate where the data come from and then gave my 2p. I can see the mmi manual extract above now.

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