My 1998 Subaru Legacy L with 97,000 miles on it is running smoothly. But towards the end of today's driving (120 miles, mostly highway) I noticed that the temperature gauge on OBD Fusion was climbing high, over 200 (220o is the beginning of the red zone). The temperature gauge on the dashboard was normal. I know that the dashboard reads a sensor on the radiator. Does the engine diagnostic port use the same gauge? I am driving around 500 miles on Tuesday and will call my mechanic tomorrow morning. I am trying to figure out how concerned to be about this problem.