Can General Motors remake its rental car?

March 14, 2013, 8:28 PM UTC

FORTUNE — That Chevrolet Impala you may have rented on your last out-of-town trip has little resemblance to the one arriving at dealer showrooms in the next few weeks. General Motors Co. has completed the overhaul of Chevrolet, its biggest-selling brand, with a new full-size sedan it hopes — check that, prays — can command retail prices from buyers.

About 70% of the current Impala sales goes to rental and other fleets, meaning they must be discounted, thereby posing a drag on corporate profit. Worse, Chevrolet (GM) and the Impala’s brand prestige have been hurt to the extent that they’ve become synonymous with rides to and from the airport.

The 2014 Impala looks like a promising departure, with nuanced sheet metal and a stylish interior. Chevrolet hopes the new Impala will grab sales from Ford’s (F) Taurus, Toyota’s (TM) Avalon and the Hyundai Azera. Overall unit sales may suffer initially, the payoff coming in higher transaction prices. “We want to reverse the proportion, so that 70% are bought at retail and 30% go to fleet,” says Chris Perry, a Chevrolet marketing executive. Prices for the new model begin at $27,535 and rise to $36,580 for the fanciest of five versions.

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The debut of the new Impala roughly coincides with the arrival of Tim Mahoney, who was recruited from Volkswagen of America to lead the revival of Chevrolet as its global chief marketing officer. Joel Ewanick had been GM’s chief marketing officer for all brands until he was sacked last July by GM chairman Dan Akerson, “for failing to meet expectations.”

Given Impala’s debut on top of a burst of other new Chevy models, Mahoney’s task will be to transform Chevrolet — whose sales base is 45% in the U.S. — into a powerhouse. Competitive brands like Volkswagen and Toyota resonate from Shanghai to Berlin. If GM can boost Chevrolet’s consumer brand perception with five models that now are sold worldwide (not including the Impala), transaction prices generally should benefit, not to mention the self-esteem of GM executives.

But Mahoney must strengthen Chevrolet’s U.S. marketing as well, which, in the view of Michelle Krebs of, has been underwhelming Exhibit A: the midsize Malibu sedan. “The segment is jam-packed with great new vehicles, and yet Malibu isn’t playing — it is last in’s consideration, purchase intent” in the midsize segment, says Krebs. “It is first place in terms of inventory, prompting GM to cut back on production twice in the last four months. The car is decent, albeit with lukewarm design; but the problem is no one knows about it and there has been zilch in the way of marketing.”

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Enhancing the prestige and desirability of Chevrolet had been the creative mission of Commonwealth, the joint venture advertising agency for Chevrolet created following the 2010 firing of Campbell Ewald. The firing and joint venture were the brainchild of the now-deposed Ewanick. Campbell Ewald had held the Chevrolet brand for 91 years with familiar campaigns like “The Heartbeat of America” and “Like a Rock.” Ewanick chose the unlamented slogan, “Chevy Runs Deep.” The latest new Chevrolet slogan was unveiled last month at the Grammy Awards, “Find New Roads.”

But now the Commonwealth venture, barely off the ground, is on the rocks. The Detroit Free Press reported this week that it was being dissolved, with McCann Erickson getting all the work and San Francisco-based Silverstein, Goodby & Partners getting the boot. If the endless turmoil of GM and Chevrolet advertising arrangements and partnerships sounds confusing, that’s because it is. But customers prefer a clear, compelling message about the vehicle they’re considering. For the Impala to have a chance, GM’s marketing must get better.