P0118 1998 HONDA CIVIC - Engine Coolant Temperature Sensor 1 Circuit High Voltage
Low Engine Coolant Level
Faulty Engine Coolant Temperature (ECT) sensor
Faulty Engine Coolant Thermostat
Engine Coolant Temperature (ECT) sensor harness is open or shorted
Engine Coolant Temperature (ECT) sensor electrical circuit poor connection
First check to see if there are any coolant leaks and if the thermostat is opening, if problem is still there replace the coolant temperature sensor.
When is the code detected?
An excessively high voltage from the sensor is sent to ECM.
Engine Light ON (or Service Engine Soon Warning Light)
P0118 1998 Honda Civic Description
The Engine Coolant Temperature (ECT
) sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the Engine Control Module (ECM
). The modified signal returns to the ECM
as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.