What's the BMW code 140 electronic thermostat control?

The BMW code 140 thermostat is in the thermostat housing on the lower coolant line. The thermostat is what measures the temperature of the coolant running through the line, and from there it can determine what temp the engine is running at. If this part is not working then the engine runs the risk of overheating, which is bad for the car. If an engine overheats it will run the risk of warping or cracking the head gasket, which will cost thousands to fix in the long run. If You get a check engine light telling You that the thermostat is not working then get it fixed right away. It is only about 200 for a full replacement so You do not want to wait.