Viano Brake Booster Sensor Failure Reduced Braking

That sounds bad. I had something similar happen on my Vito. The brake pedal felt spongy which was scary. Was the error message constantly on, or did it come and go? Did you notice any difference in braking before the error showed up? Incorrect bleeding can cause problems. I wonder if air got trapped in the system somewhere. Let us know how it goes.

The error is constant now. Braking was fine before the bleed, so I reckon you are right about the air. Did you replace the sensor in the end?

A constant error message is not good. Mine was intermittent at first, but then became permanent. Replacing the sensor fixed it for me. I'd recommend getting it checked by a workshop though. Brakes are not something to mess with if you're not completely sure. Safety is paramount.

Thanks for the advice. I replaced the pressure sensor, part cost 90€. Seems bleeding the system introduced air, as suspected. Everything is good now.