66 20 540
Necessary preliminary work:
Remove rear bumper panel
Unlock retaining tabs (1) in direction of arrow and pull ultrasound transducer (2) upward out of bracket (3).
Before installation of ultrasonic sensor (2) on wiring harness, clean plug connection!
Retaining hooks (1) of ultrasonic transducer (2) must engage exactly in mountings (3).
Make sure rubber ring (1) is correctly seated on ultrasonic sensor (2).