How to solve P0118 OBD PROBLEM code The P0118 fault code indicates an "Engine Coolant Temperature (ECT) Sensor Circuit High Input," meaning the ECM detects a voltage signal from the sensor that is higher than normal, usually suggesting an open circuit, unplugged sensor, or short-to-voltage. The engine PCM often reads this as a -40°F (-40°C) temperature, causing cold-start issues, excessive fuel consumption, and potential overheating. Symptoms of P0118 Check Engine Light is on. Hard starting, esp

P0118: Engine Coolant Temperature Sensor Circuit High Input - OBD ADVISOR