Open Limit Switch on Trane Furnace: How to fix?
The high temp limit switches usually have a manual reset button that needs to be pressed to reset. I would try a reset it may have been a fluke that it tripped, if the reset dosent trip again it is probably fine. If it trips again you will want to verify the exhaust is clear, and the fan is freely spinning (some do need oil at each end to lube the bearings) low air flow on a high efficiency system can overheat the fire box.