Heat oil in large Dutch oven over medium-high heat. Working in batches, add pork; cook until browned on all sides. Transfer meat to plate.
Add onion and water to pot; cook until softened, about 5 minutes. Return pork to pot. Add cabbage, broth, tomatoes, vinegar, caraway seeds, salt and sugar. Bring to boiling. Reduce heat to low, partially cover and simmer 30 minutes. Add potatoes; cook 15 minutes, until potatoes are fork-tender.
Stir water and flour in small bowl until smooth. Stir into simmering stew. Cook until thickened, about 5 minutes.