China should hit back with tariffs the countries who voted for and abstained. It doesn't need to be against cars cause this will hit the countries where automotive is big, and which voted against the tariffs such as Germany, Slovakia and Hungary
I think it should be some useless overpriced crap, such as luxury brands -> It will hit particularly France and Italy or, and agriculture it would hit Poland, Spain and the baltic triple Chihuahua
If you want to split the EU, which should be in China's interest, retaliation will need to hit the EU as a whole. Otherwise, countries like Germany will keep on acting like they're the nice guys to avoid Chinese retaliation, while reaping the benefits of EU protectionism. Exemptions should only be made for countries that subvert the new EU rules.
Retaliate against the whole block. And let the EU members fight among themselves over how their national economies are suffering due to other countries in the EU voting for.
If history taught us anything, one should always focus on the very few die-hard enemies and leave the wall-sitting ones alone. Beat the front running enemy then pick up the second rank and so on. Never ever beat every potential enemy all together at the same time. That is how devide and conquer works. Throwing a tantrum works only against one's objective.
During long march Jiang Jieshi orgnized containment campaigns with both his own troops and warlord troops. Communist force had in many many times hit Jiang Jieshi's troops only and left troops of other warlords alone. Communist even made deal with other warlords for safe passages. The warlords just moved unbelievably slow to close the gap, or just run away after the first shot. Think about Jiang Jieshi as the EU faction against China, the warlords as the wall-sitting faction, you will get the picture.
My advice is to pick France, Italy and Poland, three big economies, populations and car manufacturers, leave everybody else alone
for the moment. EU rules apply to every member, but China can treat individual member differently, punish the one who opening against us, reward the one openly support us and leave the silent one alone.
Remember people like Von the lier want to bind every EU countries to the same war wagen and use the China-friendly members as a human shield, beating up every EU member indiscriminately will just play into the hands of Von the lier.
Deal with what people do, not what they may think in their heads.