Heat oil in a large non-stick frying pan over medium-high heat. Add sausage and onion. Sauté until onion is softened and light golden, about 5 minutes. Add capsicum, garlic and basil. Sauté until capsicum is very tender, 10 minutes. Remove from heat. Stir in olives, vinegar, salt and pepper.
Meanwhile, cook pasta in a large saucepan of lightly salted boiling water until al dente, following packet instructions. Drain; reserve 1/4 cup (60ml) of the cooking water. Toss pasta with sausage mixture and reserved water. Serve with parmesan.