Thanks 89nk!
I did a bit of looking and it seems that many of the post-MBA positions are focused on finance, supply chain, manufacturing or marketing.
So like you said, it doesn't seem like a engineering degree is a requirement.
However, I assume it is just like every other post-MBA job, work experience within the industry is highly valued.
If you have an engineering degree and have worked in the automotive industry, it's the work experience (and knowledge of the industry) that is highly valuable post-MBA, not necessarily the engineering knowledge itself (which can also be valuable depending on the position).
RF