The all-new 2016 Cadillac CTS-V, shown in this GM illustration, is at the heart of the idea of "passion" that the brand's marketing chief wants to convey to customers. Source: General Motors Company.

Analysts, including your humble Fools, have talked a great deal about the "conundrum" that General Motors (NYSE:GM) now faces with its luxury brand, Cadillac. 

That conundrum goes like this: After decades of neglect, GM committed big bucks and big resources to develop new cars for Cadillac that could match or beat the best from the German luxury stalwarts. For the most part, they succeeded: The Cadillac ATS and CTS are no-excuses luxury sedans, with taut handling and impressive interiors. 

But so far, the new Cadillacs haven't lured a lot of buyers away from BMW and Mercedes-Benz. The problem: While the cars had come a long way, the Cadillac brand itself still needed work. Market research showed the brand was not drawing much "consideration" from those German-brand loyalists. In other words, they weren't even interested in a test drive.

How do you fix that? That's the challenge that GM put in front of newly hired Uwe Ellinghaus. Ellinghaus, a longtime BMW veteran, had joined GM as Cadillac's marketing chief.

So what will Ellinghaus do to turn Cadillac into a brand that German-luxury-brand customers will take seriously? How will he get Cadillac onto those shopping lists? 

Ellinghaus has said that it all starts with the idea of "passion." We had a few minutes with Ellinghaus at the North American International Auto Show in Detroit earlier this month, and we asked him to explain. In this short video, shot on Cadillac's show stand, you can hear what he told us.