Bring condensed soup, sugar, vinegar, and oil to a boil in a saucepan. Stir well, remove from the heat, and let cool until needed.

At the same time, bring a large pot of water to a boil; add carrots and boil until just tender, about 10 minutes.

Drain carrots and transfer to a mixing bowl. Add onion, bell pepper, and celery. Pour soup mixture over vegetables and stir until coated.