Brake Servo Pressure Sensor Restricted

[murfs3]

I am getting the "Brake Servo Restricted" message, intermittently. Have purchased replacement OEM part, and located the sensor under the cowl next to the brake master cylinder. A little hard to get to with the cowl on, but doable.

What is the trick to get this off? It seems like it should be relatively simple and just pull straight up. I was able to remove electrical "harness" and found the catch at the front of the sensor, but I just can't get it to come out. I tried putting a sting underneath the sensor and pulling up and was not able to. At one point, I heard the slightest bit of air release (vacuum hose opening sound), which may have been the closest I was to getting this out, but it didn't come out.

I tried pumping the brakes a few times with the ACC on, and with it off, but still nothing. Car was cold and had not run since the night before, and I couldn't get it off, then I fired it up for about 45 seconds to get it into the garage but still nothing.

Like I said, I feel like this should be an easy 3 minute job, but it has me baffled. I think I must just be missing how to equalize the air pressure or release it, but I couldn't find anything online other than pump the brakes.

Thank you for the help.

2017 Audi Q7 Prestige 3.0T 85K miles

[murfs3]

EASY FIX - the pressure sensor servo is a little challenging to get to, and at an odd angle. I am 6 foot tall, and I had to stand on a 4x4 to get a good view of what was going on.

I did pump the brakes a little and I felt the pedal firm up just a bit as the car hadn't been driven in 12 hours. Release the little gray wire harness clip by pushing the tab away from the sensor and then it acts as a lever and releases. What i was unable to see was that not only was there a clip at the end of the sensoro (closest to the front of the car), but there were two clips that had to be pulled back on each side of the sensor. Once those 3 clips were "opened up" the sensor pulled straight off, and you could hear the vaccuum release as the read o-ring cleared and opened up the vaccuum hole.

If you happen to drop the sensor, fear not it will just fall a few inches below to the bottom of the drain cowel (which is a good idea to clean out).

Fitment of new sensor is exact reverse order and it goes right on. Clip everthing back in place and you are good to go.

I also hooked up my OBDII scanner and cleared the codes for the servo restricted.

Hope that helps - really is an easy fix that can be done at home with a small flathead screwdriver and a little common sense and not extra large hands. No sense in spending a ton of money to have an Audi Tech do it, if you can do it yourself.

[minman26]

Would this be why I need to push the brake pedal harder than any other vehicle I’ve driven to get it to start?

[wwhan]

Did you replace with Pressure sensor, Brake booster? Audi #5Q0906207

I had the warning come up last night on my 2019 RS5.