Possible causes – Faulty Engine Coolant Temperature (ECT) sensor– Low engine coolant level– Engine Coolant Temperature (ECT) sensor harness is open or shorted– Engine Coolant Temperature (ECT) sensor electrical circuit poor connection– Faulty engine coolant thermostat Symptoms – Engine Light ON (or Service Engine Soon Warning Light) P1118 CADILLAC OBD Code Description The Engine Coolant…