Coolant Temperature Sensor For SAAB OPEL OEM 850413 1338441 1338477 1341856 4803530 4810250 5952155 6238938 7778980.It is installed in the water jacket or coolant pipeline of the engine block and contacts with the coolant to detect the coolant temperature of the engine. The ECU corrects the injection time and ignition time after receiving the temperature signal.