TPMS Question

[Tron2013A5]

After I got my tired changed about 6 weeks ago everything was fine, MMI showed green for tires...today I went through a car wash and suddenly my TPMS light went off though none of my tires are low, so I reset it. Now when I go into the TPMS indicator in the MMI it only shows gray like something is missing. Anyone got any ideas?

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[Smac770]

No idea. Scan for DTCs, see if anything comes up. 2013 A5 has indirect TPMS, so there are no sensors in the wheels. It presumes to guess that the tire pressure is different than what you calibrated (learned) originally based on the statistical analysis of the wheel speed sensor signal. Maybe water messed up one of the wheel speed sensors? But you should have a lot more issues on the dash than just a grayed out MMI option.

[Neil F]

What year do you have? The B8 as indicated above is indirect. There is not a MMI display indicating green/gray

[Dippy]

In terms of false TPMS warnings I have had a few. I only recently noticed that in the manual it suggests resetting TPMS after every time the pressures are adjusted. I had not been doing this because the adjustments have been small. I have had false warnings sometime after tyre change or if it has been a long time since I reset the system.

[Tron2013A5]

What year do you have? The B8 as indicated above is indirect. There is not a MMI display indicating green/gray

Neil, it's a 2013 A5 Cab. What I mean by display is that in the MMI under car settings, before I went through a car wash the TPMS option under car settings/service & checks would show green wheels on the display. Now they are gray despite tire pressures being fine.

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[Tron2013A5]

In terms of false TPMS warnings I have had a few. I only recently noticed that in the manual it suggests resetting TPMS after every time the pressures are adjusted. I had not been doing this because the adjustments have been small. I have had false warnings sometime after tyre change or if it has been a long time since I reset the system.

Yeah it went off right after leaving the car wash. Reset it, but now it doesn't indicate whether tires have pressure under the settings menu. They used to show green and whatever the low pressure one is. Now just gray as if the system disappeared. I'll hook it up to VCDS this weekend. Gotta be a fault somewhere.

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[Tron2013A5]

Interesting addition...it used to tell me which tire to check, lately it's just been telling me check all four tires.

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[Tron2013A5]

Resurrecting this thread because I wasn't clear enough and maybe someone can still help. Not sure if it is a sensor issue or what but when I first got my car it would tell me at least which tire was running low. Now it is only saying check all four tires even though one will be low and the rest will be fine. So is this a sensor issue? And if so how do I recalibrate them? 2013 Audi A5 Cab.

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[Smac770]

You have no sensors on the wheels, there's only the wheel speed sensors mounted in the wheel bearing housings. You have indirect TPMS, it never knows the actual air pressure or air temperature in any of the tires.

If you've ever rotated tires, changed tires, changed pressure in the tires, or otherwise did anything that would impact the rolling nature of the tires, you'd need to reset the tire pressure system. After that, the system goes into a calibration mode that might take an hour of driving to complete. Once that's locked in, the wheel speed sensor profile for each tire is stored and used as the comparison point going forward.

[Tron2013A5]

You have no sensors on the wheels, there's only the wheel speed sensors mounted in the wheel bearing housings. You have indirect TPMS, it never knows the actual air pressure or air temperature in any of the tires.

If you've ever rotated tires, changed tires, changed pressure in the tires, or otherwise did anything that would impact the rolling nature of the tires, you'd need to reset the tire pressure system. After that, the system goes into a calibration mode that might take an hour of driving to complete. Once that's locked in, the wheel speed sensor profile for each tire is stored and used as the comparison point going forward.

Thanks. That's helpful!

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[Smac770]

I reread my post and think one aspect might be misleading. If you change the pressure in the tires, you don't do a "store pressures" or whatever the menu item is in the menu interface under tire pressures for indirect systems. Unless you're changing your normal tire pressure and want it to be your new normal (maybe you used to run 34 but now you want to run 35, etc). It's whenever you change your new normal reference that you do the store pressures recalibration process. Such as rotating tires. You might still be using the same pressures, but now there's a different physical wheel/tire at each corner, so the relearning process needs to be initiated.

But not just because it got cold for a week and you added a psi or two to bring them back to your normal cold pressure. In case my prior post gave the wrong impression there.

[Tron2013A5]

I always do the "store pressures" whenever I add air. My biggest issue is that it doesn't tell me which tire is low. I understand it is an indirect system that sees when rolling dynamics change due to underinflation but it used to tell me, for example "rear right underinflated" but only says check all 4 now.

I don't know I'll dig deeper.

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[RockJGC]

I always do the "store pressures" whenever I add air. My biggest issue is that it doesn't tell me which tire is low. I understand it is an indirect system that sees when rolling dynamics change due to underinflation but it used to tell me, for example "rear right underinflated" but only says check all 4 now.

I don't know I'll dig deeper.

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Have you tried manually testing it? What I mean is this--- fill all four tires to specs, store the pressures, then after driving around for a while, pull over and lower the pressure by at least 10 psi in just one tire and see what message pops up after you start driving again. It shouldn't take very long for the wheel speed sensors to pick up on the underinflated tire. And it should tell you which tire is underinflated.

[Tron2013A5]

Have you tried manually testing it? What I mean is this--- fill all four tires to specs, store the pressures, then after driving around for a while, pull over and lower the pressure by at least 10 psi in just one tire and see what message pops up after you start driving again. It shouldn't take very long for the wheel speed sensors to pick up on the underinflated tire. And it should tell you which tire is underinflated.

I did not try that. Will do tomorrow.

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