Place the corn, vegetable broth, potatoes, onion, garlic, red chile peppers, chili powder, salt, parsley, and black pepper in a slow cooker; cover. Cook on Low for 7 hours.
Pour the vegetable mixture into a blender, filling the pitcher no more than halfway full. Hold the lid of the blender with a folded kitchen towel and carefully start the blender using a few quick pulses before leaving it on to puree. Puree in batches until smooth and pour into a clean pot. Alternately, you can use a stick blender and puree the mixture in the cooking pot. Once everything has been pureed, return it to the slow cooker. Stir the soy milk and margarine to the mixture; cook on Low for 1 hour more. Add the lime juice to serve.