Low Tire Pressure Light, Tire Pressure is Fine

[Gerthex]

Hello all, As the title states, my tire pressure light keeps coming on yet my tire pressure is fine. I know Audi does a weird calculation to find the "tire pressure" based on the wheel speed sensor readings. I would suspect I have a faulty/bad wheel speed sensor but my speedo is working fine.
Anyone run into this? What was your issue? Alignment issues? Balance issues? My car seems to drive straight, tires seem to be wearing evenly from what I can tell and, tires seem to be balanced maybe a very slight imbalance

[apeck240]

Hello all, As the title states, my tire pressure light keeps coming on yet my tire pressure is fine. I know Audi does a weird calculation to find the "tire pressure" based on the wheel speed sensor readings. I would suspect I have a faulty/bad wheel speed sensor but my speedo is working fine.
Anyone run into this? What was your issue? Alignment issues? Balance issues? My car seems to drive straight, tires seem to be wearing evenly from what I can tell and, tires seem to be balanced maybe a very slight imbalance

I'm assuming you saved the pressures in the mmi?

[Allowencer]

Could be a bad TPMS sensor on that tire. Like ^, did you save?

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[apeck240]

Could be a bad TPMS sensor on that tire. Like ^, did you save?

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There are no tpms sensors

[Gerthex]

I'm assuming you saved the pressures in the mmi?

Yes I have saved pressures after adjusting. The light comes on almost immediately after I start driving, occasionally it may take up to a day to pop back up.

[Allowencer]

There are no tpms sensors

Sorry? There isn't a sensor in the tire/valve stem?

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[Gerthex]

Sorry? There isn't a sensor in the tire/valve stem?

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Nope! Thats how most car manufacturers do it but not Audi. They use the wheel speed sensor to calculate the change in tire diameter which would have a direct correlation to tire pressure. Once below X tire diameter, the TPMS light kicks on. To me this is like the definition of German engineering lol. It is overly complicated but actually makes sense and also less parts and hopefully less cost to the consumer.

[Allowencer]

I could swear when the shop has changed my tires I saw the modules. I have 2 sets of wheels, my summers have them and my winters don't. I don't have monitoring when I have my winter tires on the car. Unsure if that changed in later years maybe? My car is an early 2010

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[Smac770]

Direct TPMS is on the MY09. MY10 initiated indirect TPMS gen2, which was developed enough by that time such that regulations would allow it. And you can be sure VAG was all over that to cut costs. And Canada didn't get TPMS at all anyway because it's not required there. That Canadian MY10 must have been retrofit with the J502 and wheel sensors.

[Allowencer]

I have a US car. I might be a MY09 then (early). Interesting.

Could indirect be retrofitted?

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[Smac770]

Indirect requires a different ABS/ESP module with additional computing resources vs. direct.

Model year when discussing the car features is always clearly denoted by the VIN. Either the 10th character is a 9 or an A. https://www.fcarusa.com/TechSupport/KB/vin-year-code

[jadatis]

I had this with also indirect pressure alarm.
Aleared to be hanging rear brake, brakeklaw had to be replaced.

So clear the message, and if it comes back after 10 minutes driving.
Park direct safely, and feel the rimms.
If at one (mostly rear) you burn your fingers, thsts the hanging brake.

Explanation is that the heat produced, highens the tirepressure, wich gives a larger rolling circumference, so ABS detects difference in rotationspeed, and explainst that as low pressure on the other side.
So still usefull message, but the other way around.

[Gerthex]

I had this with also indirect pressure alarm.
Aleared to be hanging rear brake, brakeklaw had to be replaced.

So clear the message, and if it comes back after 10 minutes driving.
Park direct safely, and feel the rimms.
If at one (mostly rear) you burn your fingers, thsts the hanging brake.

Explanation is that the heat produced, highens the tirepressure, wich gives a larger rolling circumference, so ABS detects difference in rotationspeed, and explainst that as low pressure on the other side.
So still usefull message, but the other way around.

This is exactly what I was looking for! I think this is my issue honestly. I have a manual a4 and ever since i changed my pads it doesnt seem like the car rolls back on hills in neutral as much as it used to be making me think the pad is getting hung up a bit. I can feel some pulsating from the brakes for a few months now, very minor. I have been planning on changing brakes once it got a bit warmer. I am expecting this to my issue. thanks a bunch!