Part of the problem with Japanese sales is image, but product selection and a shrinking dealer network are also to blame. Rick Brown, president of GM Japan, says they plan to address those issues by adding a couple of dealerships a year, and by shaking up the product mix. They plan to start selling the Chevy Aveo, the new 2010 Camaro, and despite the struggling economy, some new luxury cars and SUVs like the Cadillac CTS Sport Wagon, Saab 9-3X, 9-4X and 9-5.
Even though those products might help, it might be a case of too little too late. Japanese buyers might be even more hesitant than usual to buy cars from the Detroit 3 because of bankruptcy fears. It's not like Ford and Chrysler are doing any better in Japan either, with similar sales declines over the pact ten years. Heck, they aren't even buying as many domestic cars these days.
[Source: Automotive News, sub. req.]