Circuit/System Description

WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.

The drive motor generator battery control module is also referred to as the battery energy control module (BECM). The BECM will diagnose its own systems and determine when a fault condition is present. Diagnostics and system status is communicated from the BECM to the hybrid powertrain control module (HPCM) through the Hybrid LAN communication circuit. The HPCM is the host controller for diagnostic trouble code (DTC) information.

The drive motor generator battery has four hybrid battery temperature sensors, an air inlet temperature sensor and an air outlet temperature sensor. The air inlet temperature sensor is referred to as sensor 1 and the air outlet temperature sensor is referred to as sensor 2. The hybrid battery temperature sensors are located on the top of the hybrid batteries. Both the hybrid battery temperature sensors and the air inlet and outlet sensors are a variable resistor that measures the temperature. The control module supplies 5-volts to the signal circuit and a ground for the low reference circuit. The temperature sensor resistance changes with temperature. The lower the temperature, the higher the sensor resistance. The higher the temperature, the lower the sensor resistance. The BECM uses these temperature sensors to determine the hybrid battery temperature and to control the battery vent fan operation.