Circuit/System Description

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

The drive motor generator power inverter module assembly (PIM) contains capacitors and a resistor circuit intended to discharge the electrical energy stored within the capacitors. Whenever the high voltage contactors are opened, the hybrid powertrain control module connects an internal resistor circuit across the high voltage positive and negative circuits. If high voltage is detected monitored by the hybrid powertrain control module after the resistor circuit has been connected, the hybrid powertrain control module commands the motor control modules (MCMs) to connect the motor phase circuits across the DC high voltage positive and negative circuits. If high voltage is monitored by the hybrid powertrain control module after the motor phase circuits have been connected, indicating a stuck-closed contactor, this DTC will set.