Circuit Description

ECT sensor uses a thermistor to control signal voltage to PCM. PCM applies and monitors 5-volt reference signal to sensor. When engine coolant is cold, sensor (thermistor) resistance is high and PCM will sense a high signal voltage. As engine coolant warms, sensor resistance becomes less and PCM voltage drops.

Code P1114 will set when the following conditions are present.

• PCM indicates ECT sensor signal voltage is low (less than one volt) for 2 seconds.
• A failed last test code will occur on first fault.
• A history code will occur on second drive cycle with a fault.