Hi All,
I have an issue with my 2017 Audi Q5 Premium Plus 2.0T which has bothered me for more than a year. Here is the warning on the panel
"Underinflated! Please Check all four tires and Reset TPMS in MMI"

A few things I've done so far and didn't help.
1. Refill my tires to the correct pressure [33psi, cold] and Reset the tire pressure setting under MMI. The warning will be gone for a while but will come back in a few hours, so it's not the fault of tire pressure.
2. Recently replaced all of my tires to the OEM version (continental CrossContact LX SPORT) and Reset the warning. Still didn't help.
3. Went to the Audi dealer and have them inspect the vehicle. After the diagnosis, the dealer said all speed sensors are fine, but the ABS module is not able to read the data from the speed sensors. The connection between the ABS module and speed sensors is fine, so the ABS module needs to be replaced. The ABS module is very expensive (1500USD+ labor), and I can't replace the ABS module myself since it needs reprogramming.

As you may know Audi doesn't use active TPMS sensors to tell the tire pressure anymore, and the manufacturer relies on the speed sensor to check the pressure instead. Besides the warning and not getting the tire pressure, the vehicle is fully functional. However, the yellow warning really bothers me. I don't think the dealer was cheating me since they also did not recommend me to have the ABS module replaced/fixed.
I'd like to hear your thoughts!
Thanks.
Lian

 

Audi used to use TPMS sensors in the wheels (I have them in my 2006 A6 Avant), but they cheapened the TPMS system by relying on the wheel speed sensors, which our 2014 Q5 has.

 

I would scan Address 03: ABS Brakes and see what DTC(s) are present.

Initially it does not make sense that the wheel speed sensors cannot communicate to the ABS Module yet your ABS System is not producing dash warning lights.

 

I'd like to give a quick update to the thread.
Like I said initially, the dealer claimed the OBD tool is not able to communicate with the ABS control unit. There are several videos in YouTube telling you how to fix the ABS module, and most likely the MOSFETS or diodes on the PCBA are damaged. Therefore, I decided to fix and dissemble the module myself.
I first unplugged the wire harness (see picture) to the ABS module, and I can hear the sound of the motor within the module. This means the PCBA is likely to be functional. Then I reset the TPMS warning, guess what? The issue seems to be fixed and it's been at least two weeks now.
I guess it's likely the microcontroller on the PCBA is dead and needs to be reset. Since the car never lost power, all electrical systems remain active for many years.
Hopefully my feedback is helpful.