GM CEO Sees 'Robust' Auto Sales in July, August HKSCKPVIamp; Reuters

Demand is up significantly in the auto industry, and General Motors expects to see "robust" sales in August and September, CEO Fritz Henderson told CNBC Thursday.

Fritz Henderson

"Demand in the last week of July ... was about 30 percent higher than what the weekly rate was prior to that, so obviously the impact of the stimulus from the 'cash for clunkers' program was quite significant," Henderson said.

(See the full interview with Henderson)

As a result, GM is vamping up its production. But Henderson said the company is being judicious so it doesn't inundate the market with a surplus of cars.

"Some of the traditional leading indicators for at least coming out of the bottom are flashing green for our industry," he said. "While the impact of the stimulus from the 'Cash for Clunkers' would go away when the program goes away, there are still some fundamentals which would suggest that the market was begging to recuperate."

As for GM's deal with Magna over its European Opel unit, Henderson said it's too soon to say that the companies have a preliminary agreement, but he has received a revised proposal for review.

Earlier Thursday, Magna co-chief executive Siegfried Wolf had told Reuters they had reached an agreement in principle.

GM also announced it would invest $43 million to build a lithium-ion battery plant for production of its new electric Chevy Volt that will initially create 100 jobs in the Detroit area.

The Brownstown, Michigan battery pack assembly plant is scheduled to begin production in the fourth quarter of 2010 to support the launch of the Volt plug-in car later that year, GM said.