Bring condensed soup, sugar, vinegar, and oil to a boil in a saucepan.
Stir well, remove from the heat, and let cool until needed.
Bring a large pot of water to a boil and add carrots.
Boil carrots until just tender, about 10 minutes.
Drain carrots and transfer to a mixing bowl.
Add onion, bell pepper, and celery to the bowl.
Pour soup mixture over vegetables and stir until coated.
Cover and refrigerate for 8 hours to overnight before serving.
