Lower customer satisfaction with domestic cars and trucks could hurt the comeback of Detroit automakers, according to the analyst behind the American Customer Satisfaction Index released today.

Overall, the industry’s score improved 1.2 percent to 83 out of 100, according to the index’s annual auto comparison. The index is based on customer evaluations.

Detroit automakers lost ground a year after the Lincoln and Buick brands surged to the top in the 2010 index with the help of incentives, reported The Detroit News.

Ironically, Japanese automakers now relying on incentives in the wake of recalls are improving their scores.

“Japanese automakers are determined to recapture recent losses in market share,” said Claes Fornell, professor of business administration at the University of Michigan. He created the ASCI in 1994. Fornell took the index private in 2009.

“It used to be Detroit that was forced to use buyer incentives to compensate for its weaker customer satisfaction. Now, with the Japanese using discounts in addition to their strong customer satisfaction, Detroit will probably have no choice but to respond in kind,” Fornell said.

In the index, Toyota and Lexus ranked as top nameplates along with Cadillac. Four of the six nameplates that declined were domestic: Lincoln, Buick, GMC and Chrysler. Among Japanese and Korean brands, all but Mazda improved.

Ford Motor Co. ranked highest among domestic carmakers, scoring an 85; General Motors Co. followed with an 84. Both companies slipped 1 percent from a year ago.

Chrysler Group LLC is below the industry average with a score of 78. Dodge, Jeep, Chrysler and Mazda are at the bottom of the index.

The Big Three had closed the gap in the last two years but a rebound by Asian brands is erasing that, said David VanAmburg, ASCI managing director in Ann Arbor.

With incentives, Asian automakers “are beating Detroit at its own game,” he said.

Washington – The Japanese government has rejected criticism that its $3.7 billion “cash for clunkers” program unfairly excludes Detroit’s Big Three automakers, reported The Detroit News.

Satoshi Miura, a consular official in the Japanese Embassy in Washington who handles auto issues, said U.S. manufacturers could participate if they followed the same import rules as many others. Instead, U.S. companies opt to use a set of rules that doesn’t require the same emissions testing.

“The short answer is Japan believes that our program is fair,” Miura said today. “We have our ‘cash for clunkers’ program, but this is not only about stimulus but also for environmental policy.

“Any car can enjoy this program as long as they satisfy the same fuel efficiency standards, regardless if it is domestic or imported.” Miura said 43 percent of imported vehicles qualify for the program in Japan.

In a letter to the deputy U.S. trade representative Thursday, General Motors Co., Ford Motor Co. and Chrysler Group LLC called the program “another example of Japan continuing efforts to discriminate against imported vehicles.”

The program makes “the vast majority of imports ineligible for the program’s significant tax cut benefit, regardless of the vehicle’s fuel efficiency,” the letter said.

Japan is providing up to a ¥250,000 ($2,830) tax cut for scrapping a car 13 years old or older toward the purchase of a new vehicle as long as it meets the 2010 fuel efficiency requirements and a ¥100,000 ($1,130) incentive for new vehicle purchasers who do not scrap a vehicle.

Under Japan’s program, no U.S. vehicles are eligible because of special import rules; 87 percent of Japanese-built vehicles are eligible. But the Japanese government noted that program is voluntary, and U.S. manufacturers can qualify if they use the same import guidelines that other companies use.

Domestic automakers have long railed over what they call unfair hurdles to selling vehicles in Japan and have been trying to get more access to the market. It’s unclear how much a favorable change would boost U.S. exports to Japan.