Code 117 &118 engine coolant temperture low &high input , what is the cause of this reading ? I have changed the coolant , Fan . engine coolant sensor, thermostat and housing. When the sensor is pluged in the fan will not come on until the car almost reachs hot. When the sensor is unpluged the fan comes on when I start the engine or I can unplug the sensor when the car is running and the fan will come on!