Rear Parking Aid Sensor, Removing And Installing: Removing

-- RS4  : Remove the rear bumper cover. Refer to REAR BUMPER COVER, REMOVING AND INSTALLING .

Exterior Sensors: 

Fig 1: Pressing Both Catches -Arrows - To Side And Press Sensor -3- Inward From Outside

Courtesy of AUDI OF AMERICA, LLC

Exterior Sensors: 

-- Vehicles with TDI engine, LTE antenna or tail pipe trim: Remove the rear bumper cover. Refer to the appropriate service information .

-- Equipped on some models: remove the side underbody trim panels. Refer to SIDE UNDERBODY TRIM PANEL, REMOVING AND INSTALLING .

-- Reach behind the bumper cover and expand both tabs -arrows- while pushing the sensor -3- from the outside toward the inside at the same time.

-- Disconnect the connector -2- by sliding the retainer -1- back and pressing the release down.

Interior Sensors: 

Courtesy of AUDI OF AMERICA, LLC

-- Remove the bolts -arrows- on the lower section of the bumper cover.

-- Press both tabs to the side -arrows- and at the same time, push the sensor -3- through from the outside toward the inside.

Fig 2: Pressing Both Catches -Arrows - To Side And Press Sensor -3- Inward From Outside

Courtesy of AUDI OF AMERICA, LLC

-- Disconnect the connector -2- by sliding the retainer -1- back and pressing the release down.