Legacy, 81K. The engine coolant leaks for months. Since yesterday, the temp gauge fluctuates between normal and high. This morning the engine check light was on and code shows “P0125 Clsd Loop Fuel Ctrl Insufficient Coolant Temp”. Any suggestions would be greatly appreciated.

P0125, from the Service manual it states that the engine is driven and detecting load. After a specific time, as determined by the temp, the coolant does not reach operating temperature. Could be defective coolant sensor or thermostat stuck open. That's for starters, after that you get into ECM and wiring continuity checks.

Thanks for the info.