Ticking Noise Under the hood near ABS Pump - C240

[trueog]

Hey Guys my Mercedes C240 makes a strange ticking noise. Its a part located near the ABS pump under the hood of my car. Its a black part. The ticking noise is very noticeable when the car is idling or being driven at lower speeds. On the freeway I don't notice it as much, perhaps road noise drains out the sound. Does anyone know what my problem could be or what that part is?

Thanks