ericguqin@gmail.com

The 2018 Q5 is my first Audi. Firstly I was a bit shocked it doesn't have an active monitor that shows me the precise current pressure of each tire. Most of the much cheaper car I had have it.
The only related function I found is set the current pressure as "normal", and a warning will pop up when any tire goes wrong. So my questions are:

1. Does it tell you which tire goes wrong if any?
2. Does that me I have to use an old school gauge to check every single tire before I reset it?
3. Does it monitor the spare tire? the spare tire in 18 Q5 is the tiny uninflated one, so I guess it's NO?

ericguqin@gmail.com

Also, how accurate of this Audi's "using rotation speed" method compared with the regular tire sensor monitoring system?

superswiss

This question keeps coming up. There are already several threads discussing this, so do a search.. It works as well as the law requires. TPMS meets the regulations, which requires it to alert the driver if tire pressure is 20% or more low on one ore more tires. TPMS is not a substitute for using your own gauge to check the cold tire pressure before driving and regularly do a visual inspection. It never was, even for the systems that show actual pressure. Once the tire heats up, the pressure these systems show are only relevant if you track the car and want to monitor hot tire pressure and tire temperatures. The main reason Audi uses the indirect system is because it doesn't require costly sensors or extra sensors for people who keep a set of winter and summer wheels. The common understanding of the indirect system is that it uses rotating speed to figure out if pressure is low, but that's not how these systems work anymore. The first generation system worked like that, but they had significant shortcomings. One being if all four tires lose pressure at the same rate, then there is no detectable difference in rotation speed and the system wouldn't detect that the tire pressure is low on all tires. Today's systems are much more sophisticated. They use the ABS sensors and signal spectrum analysis to measure oscillations in the wheel assembly that are known to be sensitive to tire pressure. They can tell if one or more tire is low and yes, it will tell you in the dash which tire is low. I've posted lots of information on this subject if you wanna learn more about it. Just do a search.

1. Yes
2. Yes. Resetting the system initiates a 20 minute learning cycle during which the algorithms measure the mentioned oscillations and build a base profile. Once the learning cycle is over, the current measurements are continuously compared to the base profile and if a big enough deviation is being noticed, the driver is alerted. Also keep in mind that changing a wheel, rotating your wheels or even things as simple as tighten the wheel lugs require the system to be reset as the oscillations could be different afterwards and throwing false alerts.
3. No. The spare tire does not produce any measurable signals while sitting in your trunk.

rausda27

Ill argue. I got a tire pressure warning and it didn't indicate which tire it was. I had to put a tire pressure gauge on it to figure out which tire was losing pressure.

ericguqin@gmail.com

Which model of Q5 do you have? That's really bad ... especially if you got that on a highway. My 2010 RAV4 always drive me crazy by flashing the tire light but didn't say which one! but come one, that's half price car from 8 years ago!

superswiss

That would be unusual. I've had TPMS go off a few times over the years and it has always indicated which tire has the issue. Problem is that particularly with older models there is no way to recall warning messages. The details of the warning message flashes on the DIS for a couple of seconds and then disappears, so if you don't catch the message while it's being displayed, then the information is easily missed. The only thing that stays on is the TPMS idiot light. The virtual cockpit now has a way to get a list of the current warnings. Not sure if the standard analog gauge cluster with the smaller display has the same capability.

blchandl2

The tire pressure light came on in my wife's '18 Premium last week. It did not say which tire was low. I still prefer the VW/Audi system over the the others.I have owned cars the monitor each tire and provide a pressure reading and had nothing but problems with sensors failing.

daberlin

In our GEN 1 Q5 I'd have to reset the tire pressure warning system at least once or twice a year. Major temperature changes, the car sitting for an extended period of time seemed to be the big culprit in throwing the warning light. Ironically, I never had a nail get the Q5's tires so I never saw the system work 'as designed'. However, my Porsche is a nail magnet and having a real time system certainly has it's advantages. As for a preference of the Audi rotational speed vs. actual TPMS systems in each tire, it's a personal preference and I think, more importantly, a cost question. I like knowing what the real time tire pressures are in my Porsche. On the track, over long distance trips where I'm concerned about tire performance, it is a nice peace of mind. But, at $200 per battery installed, that's an $800 every 5 year (or so) cost that I'd prefer not to have.

superswiss

Only once or twice a year? How often do you check your tire pressure? I reset mine every other week after checking and adjusting the tire pressure. It's supposed to be reset every time you adjust the tire pressure. A typical tire loses about 1 psi every month just due to air escaping and every 10F drop or increase in temperature is another 1 psi up or down.

rausda27

2018 Premium Plus. It doesn't tell you which tire it is. Trust me.