I have 2005 ford Focus and the O/D was flashing on a new rebuild. It had only 10 miles on it. No codes in the OBD I I The output sensor failed. It was flashing on speeds over 30 mph witch the overdrive would kick in at that speed. If you came to a stop it would go off. Also seemed kinda sluggish like it was lacking power. Started with replacing the speed sensor and that did not do it went to the output sensor and that was it. SO OUTPUT SENSOR WAS THE PROBLEM. All fixed
Good for you. Glad you are back on the road with a correctly running car. Just curious, what’s the functional difference of the output sensor compared to the vehicle speed sensor? You’d think the transmission would know the vehicle speed b/c it is connected directly to the wheels.