DTC P0118: Engine Coolant Temperature (ECT) Sensor Circuit, High Input: Condition

WARNING: This page is about a different car, the 2002 Suzuki Grand Vitara. However, it is still accessible from the selected car via links, so may be relevant.

DTC is set when ECM (PCM) detects ECT sensor input voltage is more than 5 volts for 5 seconds. Possible causes are:

ECT sensor malfunction.
ECM (PCM) malfunction.