I have a 2005 Ford Taurus. It has about 167k miles on it. A few months ago the check transmission light came on. It was low on fluid so I refilled it and the light went over. 2 weeks ago it came back on as I was driving and then went away when I turned it off. Today it came back on. The fluid levels are fine. I have a Foxwell code scanner and it’s not showing any codes. It doesn’t shift any differently than it has been. What could be causing this? Is it safe to drive?