agjil

Hello,

from what I understand, Audi's tire pressure monitoring system in the 2012/2013 A6 does not display the actual psi readings, but instead displays a warn sign if the pressure is too low.
Is this correct?

If so, at approximately what psi level does the tpms display the warning sign?
The recommended psi for my 2012 A6 I believe is 38 for the front and 41 for the rear wheels.

I haven't been pumping in air to the tires for a while, and I think the pressure is probably pretty low at this point, and I haven't seen the tpms warning yet, so that makes me wonder whether it is actually working.
I'm planning on checking out the exact psi readings on my way home today, but I was just curious if the tpms is reliable, and what others have experienced with it.

Thank you-

Mrmillergd

I had this problem with my 09 A6. The TPMS system never came on even though the tires were probably 10 lbs low when I checked. TPMS did not indicate low pressure. I think it is only good for detecting if one tire is substantially lower than the others rather than if all 4 are slowly losing pressure.

ben_aip

No 1 - the tires pressures that you've stated may be too high - look in the manual under normal load, your driver's door plate is for max load only - you will even enjoy a smoother less harsh ride if you follow the pressure setting in the manual, depending on your tire size.

No 2 - this here is how Audi's TMPS works:-
"The tire pressure indicator in the instrument cluster informs you if the tire pressure is too low or if there is a system malfunction. These characteristics can change and cause a tire pressure warning if the tire pressure in one or more tires is too low; the tire has structural damage; or the tire pressure was changed or the wheels rotated or replaced but the TPMS was not reset. An indirect tire pressure monitoring system (TPMS) compares the tire tread circumference and vibration characteristics of the individual tires. If the pressure decreases in one or more tires, this is indicated in the instrument cluster with a warning symbol."

mikem33

The newer Audis don't have pressure sensors in the tires; instead, they use the ABS sensors and analyze the waveform to determine if a tire is low. Thus, the car has no tire pressure information at all.

In order for TPMS to work with this system, you need to set the pressures at the correct value and then reset the TPMS learning/calibration in the MMI. Once you do this, the system will learn the waveform/signature for the particular tires and particular pressures. After about 20 minutes of driving at various speeds, the system finishes 'learning'.

In theory, the system will warn you if a tire is 20% low, and can figure out both single-tire and multiple-tire scenarios. I have not actually tried it to make sure it works.

Hope this helps. While there are no absolute readings, this approach allows for using rims without the TPMS sensors, avoids the replacement of sensors due to breakage when changing tires/batteries dying, etc. and in general makes for a more reliable, easier to maintain TPMS system that still provides useful information about dangerously low pressures. But you can no longer check your tires without using a gauge and getting some of that Audi brake dust soot on your fingers.

mwar99

It will also tell you which wheel is low. When my left rear had a nail in the tire it told me which wheel needed attention - of course with the rate of the air leaving the tire I couldn't miss it anyway.

tenspeed

Using a TMPS system is like relying on the electronic oil level indication in the engine. I trust but verify with a tire gauge.

Check your pressures every couple of months. Tires will lose about a pound for every 10 degrees Fahrenheit so pump them up in the fall. Compare the sidewall bulges. Don't forget the spare tire.

While your walking around, occasionally touch the wheels after a drive to see if there is excess heat from a brake hanging up or a wheel bearing on it's way out.

agjil

speaking of the devil, the TPMS warning light came on on Friday just as I was driving towards a local gas station to check the psi readings on the tires.
I was kind of glad to see it, as it meant the TPMS actually works.

z06bigbird

Read post by Ben Alp. He has accurate info.

keithl

I am a bit confused, so if the car does not do direct read out and relies on ABS and tire diameter, why is there TPMS sensors at parts sites?

http://www.titantpms.com/tpms/audi-a...uminum-9600008


If you are sensors is the receiver unit in the car to get a direct readout?

snagitseven

Audi used actual active TPMS sensors prior to 2010. My 2009 A4 had them. The 2010 on uses the passive system. I have no idea why anyone would buy these as there's no electronics in the C7s to deal with the signals. Even if there were, my experience with both is the active sensors were no more or less accurate than the passive ones but were an added expense to replace. Also, the '09 A4 did not display PSI or could alert which tire was low, same as now. AFAIK, only the A8/S8 have channels to read the actual psi of all four tires.