12 Volt Battery System Description (3.5L Engine)
Overview
This vehicle is equipped with a 12 volt battery sensor on the battery negative terminal. Some models come equipped with the 12 volt battery fan in order to prevent damage to the 12 volt battery by lowering the temperature of the 12 volt battery. The 12 volt battery fan motor is controlled by the PCM.
12 Volt Battery Fan Control
The 12 volt battery sensor measures battery voltage, battery fluid temperature, and charge/discharge currents. According to these readings, the battery fluid temperature, internal resistance, and state of charge are sent as signals from the 12 volt battery sensor to the PCM.
Regardless of the vehicle speed, the 12 volt battery fan motor does not work when the 12 volt battery temperature is low. When the 12 volt battery temperature rises more than the threshold, the 12 volt battery fan motor will run at low vehicle speeds and not run during high vehicle speeds. If the 12 volt battery temperature rises further, the 12 volt battery fan motor will run continuously regardless of the vehicle speed.
Failsafe Function
The information from the 12 volt battery sensor is first sent to the gauge control module or PCM by the LIN and is then sent to the PCM using the F-CAN. Commands are sent to the 12 volt battery fan motor by the PCM using the LIN. When the PCM does not receive information from the 12 volt battery sensor due to a failure with the sensor, gauge control module, F-CAN, or LIN, the PCM activates the failsafe control which turns on the battery fan motor if the MAF/IAT sensor signal indicates a temperature of 95°F (35°C) or more.