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 hybrid battery assembly consists of 40 individual batteries. Each battery is rated at 7.2 volts. A pair of batteries is rated at 14.4 volts. The batteries are connected together in a series circuit. The BECM monitors the hybrid battery voltage on every two batteries for a total of 20 locations, across the battery assembly. The BECM monitors and compares these 20 voltage measurements, if the BECM detects a voltage difference greater than a calibrated value on any two consecutive hybrid battery voltage measurements this DTC will set.