"Great products and improving economic fundamentals are really driving our business," Johnson told analysts and reporters during a conference call.
Sonic, Cruze up
GM sold 7,900 Chevy Sonics in February -- nearly triple the year-earlier sales of the car it replaced, the Aveo, and the highest mark since the car was launched in August.
Sales of the Chevy Cruze totaled 20,427 units, the first time Cruze sales topped the 20,000 mark since August.
Johnson attributed the rise in small-car sales to the success of its new offerings rather than the rise in gasoline prices throughout the month. He said nearly 40 percent of GM's overall sales are derived from vehicles that get at least 30 mpg on the highway vs. 16 percent three years ago.
"I think the strength of our broad-based portfolio is what's helping us achieve these kinds of numbers," he said.
Another strong point was sales to commercial customers, such as contractors and farmers, which rose 35 percent. Heavy-duty versions of the Chevy Silverado and GMC Sierra pickups rose 28 percent and 20 percent, respectively.
Chevrolet sales rose 6 percent to 151,197.
Cadillac, Buick off
Cadillac weighed on GM's overall results. Sales fell 27 percent, to 11,505, from a year earlier, which had been the brand's best February on record, Kurt McNeil, Cadillac's sales chief, said. He blamed the results on the phaseout of the DTS and STS sedans and an 81 percent drop in sales to rental fleets.
Buick sales fell 11 percent to 14,023. GM sold 1,688 of the new Verano, which was launched in December. That helped offset a 29 percent sales drop for the mid-sized Regal sedan. Many dealers have said that sales of the less-expensive Verano could cannibalize Regal sales.
GMC sales were flat, inching up 47 units to 32,581.
In January and February of 2011, GM offered a loyalty lease deal that allowed GM customers to waive the last three or four monthly payments if they bought new cars. That drove heady results during those months, which GM has struggled to match this year despite the improvement in the overall market.
March sales last year suffered a hangover from that binge, which signals that GM could post a strong increase next month compared with the weak year-ago numbers.