The Powertrain Control Module (PCM) has been programmed to monitor the following cooling system components:If the engine has remained cool for too long a period, such as with a stuck open thermostat, a Diagnostic Trouble Code (DTC) can be set. If an open or shorted condition has developed in the relay circuit controlling the electric radiator fan, a Diagnostic Trouble Code (DTC) can be set.If the problem is sensed in a monitored circuit often enough to indicate an actual problem, a DTC is stored. The DTC will be stored in the PCM memory for eventual display to the service technician.To read DTC's and to obtain cooling system data, (Refer to 25 - EMISSIONS CONTROL/ON-BOARD DIAGNOSTICS - OPERATION).