Honda Pilot: 12 Volt Battery System Description - Control/Function

Battery Fan Control

The 12 volt battery sensor measures 12 volt battery voltage, 12 volt battery fluid temperature, and charge/discharge currents.

According to these readings, 12 volt battery fluid temperature, internal resistance, and state of charge are sent as signals from the 12 volt battery to the gauge control module. The PCM actuates the 12 volt battery fan motor based on the vehicle speed and the 12 volt battery sensor temperature signals from the gauge control module.

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 threshold, the battery fan motor will run at low vehicles 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.

12 Volt Battery System Description - Failsafe Function

The information from the 12 volt battery sensor is first sent to the gauge control module by the LIN and is then sent to the PCM using F-CAN. Commands are sent directly to the 12 volt battery fan motor by the PCM using 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 fail-safe control which turns on the battery fan motor if the MAF/IAT sensor signal indicates a temperature of 95 ºF (35 ºC) or more.

12 Volt Battery System Description - Overview

This vehicle is equipped with 12 volt battery sensor on the 12 volt battery negative terminal, and is 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 Management System Description - ComponentsA/C System Description - A/C Pressure Sensor