You echo my main concern–that even though the engine itself has no problem, if the sensor is faulty, it may give bogus information/instructions to the cooling system that cause an overheat. I would love to know if the temperature gauge on my dash panel is driven by that sensor, if it is a separate sensor.
In another post on this forum, I found a post by another Saturn owner that stated there are two lights that can come on to notify me about problems: the Service Engine Soon as well as the traditional Check Engine, and that the SES light may only indicate that my car is coming up on its due date for some scheduled maintenance.
If anyone knows for sure about these, any info would be much appreciated.