Circuit Description

The powertrain control module (PCM) uses the temperature of the engine coolant for engine control and as an enabling criteria for some diagnostics. The PCM monitors the starting engine coolant temperature, engine loads, engine speed, and elapsed time to calculate engine coolant temperature (ECT). The PCM uses the calculated temperature to determine if the engine has warmed up to the closed loop temperature or to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach the closed loop temperature, diagnostics that use the ECT as enabling criteria, may not run when expected. If the engine coolant temperature fails to reach the closed loop temperature or the thermostat regulating temperature, before a predetermined amount of air flow enters the engine, the applicable DTC sets.