Fault

My car is 2001 automatic 206 celloid valve and transmission fluid was changed. Snow sport lights went out. After the maintenance. But two days later snow and sport lights started to come on again. The mechanic checked the oil pressure should be 280. He said it had dropped to 200. He connected it to the machine. He said there might be a problem in the brain. Why do you think it does this? I am waiting for your help. It protects itself when the lights come on. Tamoada does not work.