Description - engine management (ENGINE MANAGEMENT SYSTEM - V8) (page 16 of 43)

ENGINE MANAGEMENT SYSTEM - V8

DESCRIPTION AND OPERATION 18-2-21

Thermostat Monitoring sensor

The thermostat monitoring sensor is located in the radiator, adjacent the bottom hose. The ECM compares the 
temperature measured by the thermostat monitoring sensor to the temperature measured by the ECT sensor. If the 
difference between the two readings is too great, the ECM determines the thermostat is stuck. In this case, the ECM 
registers a fault code in its memory.

The thermostat monitoring sensor works as a Negative Temperature Coefficient (NTC) sensor. As temperature rises, 
the resistance in the sensor decreases, as temperature decreases, the resistance in the sensor increases. With this 
information, the ECM is able to monitor the performance of the thermostat. The normal operating parameters of the 
thermostat monitoring sensor are as follows: