Uwe Ellinghaus doesn't like to see Cadillac explicitly comparing itself to German luxury competitors in its ads. But he's determined to see Cadillac adopt the marketing strategies used by those rivals, including his former employer, BMW.

The results of that drive will show up in April, said the 45-year-old marketing chief, when Cadillac unveils its range-topping CT6 sedan, the first car to carry its new vehicle-naming system, at the New York auto show, along with a revamped strategy that will seek to position Cadillac not just as a car brand, but as a pure luxury brand.

"Johan de Nysschen, my boss, and I always say we want to build the first luxury brand that just happens to make cars," Mr. Ellinghaus said in an interview at the Los Angeles Auto Show. "That sounds like a joke, but we're serious about it."

The new image will come from a General Motors division that is in transition under Mr. de Nysschen's leadership, preparing to distance itself from the GM mother ship in Detroit and set up as a new business unit with its own headquarters in New York. After a hot 2013, Cadillac sales have slid this year as higher sticker prices repelled customers, leading to gluts of CTS and ATS sedans on dealer lots.

'Declare me nuts'
Mr. Ellinghaus, a German who came to Cadillac in January from pen maker Montblanc International after more than a decade at BMW, said he has spent the past 11 months doing "foundational work" to craft an overarching brand theme for Cadillac's marketing, which he says relied too heavily on product-centric, me-too comparisons.

"In engineering terms, it makes a lot of sense to benchmark the cars against BMW," Mr. Ellinghaus said. But he added: "From a communication point of view, you must not follow this rule."

Rather, he says, Cadillac needs to project unrestrained self-confidence, the way its competitors do. The brand communications rolling out next year "will not play with Cadillac's ambivalent image with a twinkle in the eye and say 'no more crappy cars,' or 'no longer your grandfather's car,'" Mr. Ellinghaus said. "Luxury brands need to display confidence. They have confident, very educated customers who only accept brands on eye level."

Neither will Cadillac be defined by phrases like "American luxury."

"Firstly, if you need to say that you are luxury, you are not luxury," Mr. Ellinghaus said. "Louis Vuitton does not say they are luxury. They simply are. Secondly, it's not meaningful. We realize that even in the U.S., people don't understand what makes American luxury different from European luxury."

The rebranding effort will be wide-ranging, Mr. Ellinghaus said, delivering a consistent image across all media, including TV, print, online, showroom appearances, auto show displays and events. Mr. Mr. Ellinghaus said he wants to "reinject some Americana into the brand. I want this brand to be bolder, more optimistic and capture people's imagination far more.

"And again, like with the nomenclature change, many people will declare me nuts, which I am," he quipped. "But the changes at Cadillac are not evidence thereof."

Mr. Ellinghaus wouldn't discuss whether any changes are coming to its relationship with ad agency Lowe Campbell Ewald, part of the giant Interpublic Group. He said a recent dismantling of Rogue, the alliance of Interpublic firms that handled Cadillac's account, was an IPG-led restructuring initiative to help Cadillac's push to be a global brand. But he said it was too soon to judge the results.

'Breathing space'
In the meantime, he's grateful for support from Mr. de Nysschen, as well as CEO Mary Barra and President Dan Ammann, for the changes he's pushing and for the move to New York, saying it will provide the "breathing space" that Cadillac needs from GM's other brands as well as a different talent pool.

"When I recruit new people, I do not need petrolheads," he said. "We have more than enough petrolheads, and we will still. I need people with experiences in other industries, but with luxury brands."

Mr. Ellinghaus said the new naming system is his initiative, and a direct response to what the Germans do to establish a hierarchy among their vehicles. Germans didn't invent hierarchy, Mr. Ellinghaus said. They merely adhere to it better than Americans.

"Whether we like it or not, customers come to the showroom and say, 'Cadillac, what's your 5 series? What's your A4?'" Mr. Ellinghaus said. "Cadillac in the past said that 'We don't do that. This is not a hierarchy we have.' … No. If we want to play with the big boys, then we need to accept the rules of their game."

Mercedes-Benz recently issued a complex diagram to explain a realignment of names across its vast product portfolio. At Cadillac, the rules will be simpler for now. All the new sedans will take a CT prefix -- C for Cadillac and T for tourer -- along with a number designating its place in the hierarchy. SUVs and cross-overs will use XT and a number.

New names will be introduced over time as vehicles are redesigned or added to the lineup, Mr. Ellinghaus said, rejecting the quick-change "Infiniti route." After the CT6, the next to switch will be the successor to the SRX, and then the updated CTS and ATS.

"So this means we muddle through for a few years [until] one day, all the cars have the new nomenclature," Mr. Ellinghaus said. "That's not a happy picture -- I accept that," but he'd rather not "muddle through forever."

The Escalade name won't be touched. "That's a brand in its own right," Mr. Ellinghaus said, adding that the ELR plug-in hybrid will also sit outside the traditional model hierarchy.

So why No. 6 for the range-topper? Mr. Ellinghaus notes that the new car will be priced and sized between BMW's 5 series and 7 series, and Audi's A6 and A8 but a "luxury brand always underpromises and overdelivers."

"If we had called the car CT7, it would have been compared to the 7-series long wheelbase, and it is not that expensive and not that big," he explained. "And same with CT8: It would have been compared with an Audi A8, and still it is not there."

The CT6 will be the top of the range, but "it's not the end of our aspiration," Mr. Ellinghaus said. "We can definitely, long term, imagine a car on top of that even. I'm not saying we will, but we are definitely dreaming high."

--Krishnan M. Anantharaman is a reporter for Automotive News