Hiace radar sensor failure

I had a similar issue with my 2019 Audi A4. Different car, but the symptoms sound identical. For me, it was a dirty sensor. Have you checked the sensor itself?

Where is the radar sensor located on the Hiace? Is it easy to get to and clean myself, or should I take it to a shop?

On the Audi, it was behind the front bumper, fairly accessible. I'm not sure about the Hiace, but I imagine it's similar. Cleaning it might solve it, but these radar systems are sensitive. If cleaning doesn't work, it might need recalibration, which is best left to a workshop. Cleaning wasn't enough in my case; recalibration fixed it.

Thanks! I checked the sensor for dirt first. I took it to the workshop, and you were spot on - it was a dirty sensor, but needed recalibration. Total cost was 45€.