The general meaning of the engine P0118 Code is Engine Coolant Temperature (ECT) sensor circuit high open problem. There are some cause of the car engine problem and the problem can be the ECT sensor range input to the ECM went to 4.91 or less than -40 deg. F representing an open circuit in the sensor, connector or cabling. There are also several symptoms what you can judge for finding the right meaning of the engine problem. The symptoms are the car engine may run coarse and hesitate until the engine warms up and another is the engine should run near to usual once the engine warms up.