Drive with caution — fix soon.
This code is set when the engine coolant temperature sensor sends a signal that's too low, which the computer reads as an unusually hot engine. Because the ECU relies on this sensor to manage fuel, fans, and timing, a bad reading can cause the car to run rich and the cooling fans to behave oddly. The fault usually lies in the sensor, its wiring, or a short to ground.
$100 – $300
Varies by vehicle and root cause.
For short distances, usually yes, but keep an eye on your temperature gauge. Since the sensor reading is unreliable, you can't fully trust the dashboard, so get it diagnosed soon.
Commonly $100 to $300. The coolant temp sensor itself is inexpensive; most of the cost is labor and any wiring repair needed.
It's a moderate concern. The engine usually still runs, but the false 'hot' reading can hurt fuel economy and mask a real overheating problem, so don't put it off.
Not by itself. The code points to a low sensor signal, not real heat. Still, confirm with the temperature gauge and a scan tool, because a faulty sensor can hide a genuine cooling issue.