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 current sensor is mounted inside the drive motor generator battery assembly. The positive high voltage cable that foes to the positive contactor relay passes through the current sensor. The current sensor detects the amperage that flows in and out of the hybrid batteries. The BECM monitors and supplies a 5-volt reference signal to the current sensor. The current sensor has a return voltage signal between 0 and 5 volts to the BECM. The current sensor return voltage signal is in proportion to the amperage going in and out of the drive motor generator battery. A return signal voltage of the current sensor above 2.5 volts indicates that the drive motor generator battery is being discharged and a return signal voltage below 2.5 volts indicates charging. The hybrid battery current sensor has 3 measurement ranges in order to maintain accuracy. The ranges are low, medium and high. The measurement ranges of the current sensor have some overlap with each other. The low range measures from -22 to +22 amps. The medium Range sensor measures from -52 to +52 amps. The high range current sensor measures from -250 to +250 amps.