Slight clonk soon after turning on

[XXL]

My igenius said it is a valve from the heatpump. That also would explain why not everyone has it. It comes about 30 seconds after startup. It can be pretty load and you can feel it also. It is not the doors looking, this clunk is much loader.
I had it from day 1, 21/11/2014.

If it was the ABS system, everyone should hear and feel it, that is not the case.

 

[alohart]

Upon each startup, our i-MiEV clunked toward the rear after moving forward a short distance. This was the ABS doing something (self-check?). Because of our i-MiEV, I am attuned to such a clunk but have never heard our i3 BEV clunk even though it has a heat pump, an ABS, and automatic brake washing (really?!). So I'm not liking the heat pump, ABS, or automatic brake washing explanation.