1994 Geo Metro - Coolant Temperature Sensor

What Is A Coolant Temperature Sensor?

The coolant temperature sensor on your vehicle monitors the temperature of your cooling system and feeds the temperature gauge or temperature warning light on your dash. This helps prevent damage to your engine due to overheating, which may be caused by low cooling system levels, radiator or thermostat failure, and other factors. Coolant temperature sensors also deliver information to your engine control module (ECM) to prevent engine damage by engaging limp mode or making other adjustments. With time and due to exposure to high temperatures, the coolant temperature sensor or switch may wear out and send inaccurate readings or a complete lack of signal to the ECM, gauge, or warning light. This may result in especially low or high coolant temperature readings, your vehicle underperforming, or your Check Engine light may come on. In some cases, you may not notice any symptoms of failure, but your engine may overheat without warning because your temperature light does not activate. If your engine is frequently overheating or using more gas than usual, this could be an indication of cooling system problems, so it's best to check your coolant level and condition to determine the source of the issue. If your temperature light fails to activate, or if your dash gauge is not working, you may need to replace your coolant temperature sensor to stay aware of problems in your cooling system. At O'Reilly Auto Parts, we carry replacement coolant temperature sensors and switches for most vehicles, and can also test Check Engine lights for free to help you make an accurate and informed diagnosis before starting your repair.