snagitseven

Unfortunately having active sensors doesn't necessarily indicate a specific tire. For example, my '09 A4 was the last year for active TPMS sensors in B8s and did not indicate which wheel was down, just that one of them was. On the other hand, the A8 with active sensors not only specifies which tire but also shows PSI for each.

qqq1970

I was on I-90E two weeks ago at night when TPMS alerted rear left. Keep going for 50 miles at full speed and didn't feel the car was pulling, until I pulled over at service station and noted the tire was low. Inflated the tire and limped 20 miles to a rest stop when tire was flat. Thanks for TPMS I inflated the tires before it got completely flat on the interstate in the middle of the night.

newmoon

I also find the system throws off warnings rather unexpectedly, so it's not really reliable.

Once I went on a roadtrip so I pumped up the tires to the pressures listed on the door jamb for a full load. However, I forgot to reset the system in the MMI for the new pressures. Finally, about 750 miles into the trip, the tire pressure warning came on, so I pulled over and checked all the tires with a manual gauge. (Note that the pressures are now all increased from being heated up from driving). I think one tire was at 38 psi, and the others were at 40 psi. I couldn't find any puncture in the low tire, so I pumped it up to 40 psi, reset the system, and continued on. To this day (maybe 10k miles later) I haven't found a leak in any of the tires.

So the system is quite strange. For some people it seems not able to detect a flat tire, and for me, it gave a false alarm. So I'm going to just continue to check the pressures manually.

zeab

And that is your opinion and I do respect it. Just saying from my experience this is what I found. Feel free to take for what it's worth. I will have to admit I am a little amazed how quiet and smooth the drive was on a totally flat tire. Feel free to try it yourself.

snagitseven

Thanks, but I think I'll pass. Smooth as the ride may be, I would rather have a flat tire repaired before destroying it on the road.

DB22

I am not sure that I could tell the difference between driving on the rims or 20 inch P Zeros at 46psi either!

dwboston

Which is why I said I prefer Acura's TPMS implementation, which shows a readout in the MID of each wheel's tire pressure. Pretty easy to figure out which wheel is low when you can see the readout for each wheel. Sounds like Audi's active system (except for the A8) sucked.

How hard can it be to do this when Acura can do it for every car in its lineup?

snagitseven

FWIW, my 2013 A6 manual on page 260 shows a graphic with a message that indicates which tire is low. Not true PSI readouts like the A8 direct system but still useful with the passive TPMS system.