YOUNTVILLE, CA – Toyota Motor Sales U.S.A. Inc.’s Scion brand will stage the unveiling of a concept car at April’s New York auto show that hints at a fourth production model.

“It will be a concept of a vehicle that will fit into the line, not a replacement of an existing vehicle,” Bob Carter, group vice president and general manager-Toyota Div., tells Ward’s here during a Toyota Prius media event.

A fourth model long has been discussed for the brand’s lineup, which now consists of the xD subcompact, boxy xB cross/utility vehicle and tC sport coupe.

While Scion sales started out strong after the youth brand’s 2004 national rollout, they have slowed over the last several years. The tC has aged and product cadence has became an issue. The ’06 xB and xA were extended until the debut of the second-generation ’08 xB and new xD in mid-2007.

The xD took the place of the xA as the subcompact in Scion’s lineup, although former Scion head Mark Templin, now general manager for the Lexus Div., told Ward’s in 2007 he wanted to see a return of the xA nameplate.

Reports last year suggested the Toyota iQ subcompact from Europe could fill that void, arriving in the U.S. as a Scion.

While Carter is mum on details of the New York concept car, he emphasizes the vehicle will not be the next-generation tC sport coupe, which eventually will be replaced. The tC debuted in 2004 as an ’05 model.

The coupe quickly became Scion’s best-selling model, but after suffering a 38.5% volume loss was eclipsed by the xB in 2008, which delivered 45,220 units compared with the tC’s 40,980, Ward’s data show.

Trying to keep the excitement and sales momentum going for coupes has proven problematic for most auto makers, Toyota included.

“You sell the heck out of them for 16-18 months, and then you buckle down for quite a while,” Carter says, adding the coupe segment in the U.S. now is a “shadow” of its former self in light of the recession.

“What’s the 2-door coupe of the future? It may not be a 2-door coupe,” he says.

Although Carter is enamored with the notion of a “sporty, emotional” car in the $30,000-range for the Toyota brand, he also knows money for product development is tight and there are other priorities, such as the Prius.

Toyota has put production of its 2-door Camry Solara convertible on hold due to bloated inventories, and a project to develop a coupe with Fuji Heavy Industries Ltd., maker of Subaru, has yet to be “green-lighted,” Carter says.

Toyota holds a 16.5% stake in Fuji Heavy, which had said it wanted to build the jointly developed rear-wheel-drive car powered by Subaru’s boxer engine at a new plant in Ohta, Gumma prefecture, Japan.

However, Toyota recently announced it was cancelling its involvement in the plant’s construction. The model now is to be built in an existing FHI facility, a Subaru of America Inc. spokesman says.

cschweinsberg@wardsauto.com