Very faint clicks at stop from brake actuator

If you don't hear clicks when you open the car door to drive it after not driving in a while you can hear accumulator pump powering up. If that's the case, keep searching for another source for the clicks.

 

The release valve for one of the brake lines could be leaking slightly, so that the apply valve for that same line has to repeatedly, briefly, click open to maintain the pressure in that line while you are holding the brake.

What leaks through the release valve returns to the reservoir, and if you're there holding the brake long enough, the pump will eventually have to cycle again, but if the leak isn't big you might notice the clicking before noticing any drastic increase in the pump cycling.

 

All of the apply and release valves are contained within the actuator. I don't know whether a stethoscope on the lines would allow you to pin down a particular brake line—or what good that would do, as nobody really takes the actuator apart or replaces individual valves in it.

 

Yes, but it'd be interesting to know...

 

The bad news is the brake actuator has no rebuilt or aftermarket options and most used ones are either the wrong part or are likely to be bad after sitting on a junkyard shelf.

The good news is yours is still good with no codes. It could stay that way for months or years.

The kind of good news is some shoppers have bought a new one and had it installed for as "little" as $500 parts and $300 labor. Parts from an online Toyota dealer during a holiday sale. Labor from an experienced independent. A few have bought the part for $1,000 and struggled to install and set it up with Techstream or equivalent. Most pay a dealer around $2,400 turnkey.

$500 part
Fuel Economy Drop After Speed Sensor Replacement | Page 2 | PriusChat

 

Speaking of Audi... This new 3rd of 3 Rich Rebuilds video of a $160K Audi he got for less than $10K with a supposed "blown engine" when it turns out engine is fine will inspire you to be optimistic about all Audi problems: