Circuit/System Description
WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM) monitors the temperature of the engine coolant for engine control and enabling criteria for some diagnostics. The ECM estimates the amount of energy generated to calculate a target engine coolant temperature (ECT). If the ECT fails to reach the thermostat regulating temperature, before a predetermined amount of energy is generated engine, the DTC sets.