They may be coming. From the FT:
China is preparing to launch a trade investigation into whether US carmakers are being unfairly subsidised by the US government, according to people familiar with the matter.
...
General Motors and Chrysler have received about $60bn in government bail-out funds, though Ford has received nothing.
Washington has also provided substantial aid to US and foreign carmakers, as well as parts suppliers, to encourage investment in “green” technology.
The wildly popular “cash-for-clunkers” sales incentive scheme this summer was also a boon for both US and foreign manufacturers.
There's also an anti-dumping petition: "China has received an anti-dumping petition as well, which asks for investigation into whether US car exports are being sold at unfairly low pries." Is it possible that actions like these will affect how the U.S. views AD/CVD?
Meanwhile, over in the EU:
European Union regulators said Thursday they would probe plans for Audi to receive a euro49.5 million ($73.19 million) subsidy from the Hungarian government to help the car maker upgrade a factory.