Hello, I actually looked at the engine of my Phaeton (3.0 TDI) for the first time today without a plastic cover. I noticed a “box” that sits in the direction of travel left between the engine and the body. The cable from the “box” has a connection to the rail tube and another junction. On the box is a small selector switch, which stands at my Phaeton on “2”. What is this: sensor? ECU? Please enlighten me. Thank you! Greeting André