Engine management system faulty

I received this warning on Wednesday last week while in traffic. It disappeared for a while after the exclamation appeared on the panel. The car continued to run smoothly. There was no problem with the warning. I received the same warning today (Saturday). After the first warning, I traveled 430 km. There is no problem with the vehicle. It works smoothly, but the warning continues. What do you think can happen

Your vehicle should be connected to the original diagnostic tool in order to reveal the problem of instant engine electronics related fault code.

I took it to the master today. the fan resistance had to change. It was resolved when it changed.

thank you for the information.