Circuit/System Description

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

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 drive motor generator control module through serial data. The drive motor generator control module is the host controller for diagnostic trouble code (DTC) information.

The drive motor generator battery contains 2 high voltage (HV) contactors and a current limit relay. The contactors allow the high voltage DC batteries to be connected to the vehicle or safely contain the DC high voltage within the drive motor generator battery assembly. The two contactors are a positive HV contactor, negative HV contactor, and current limit relay. These contactors close and open in sequence and are controlled by the drive motor generator battery control module. The control circuit for the contactors use a buss bar attached to the circuit board and the drive motor generator battery control module supplies a ground to turn them on and off individually. The drive motor generator battery control module monitors the control circuit voltage to these contactors and 12 V reference circuit internal to the control module to determine if the circuit is open by comparing the two voltage readings. If the drive motor generator battery control module detects 2 consecutive failed high voltage precharge events, a precharge wait time is activated by the drive motor generator battery control module. This precharge wait time limit is to allow the precharge circuit internal to the drive motor generator battery assembly to cool down. The precharge wait time counts down in seconds and is displayed on the scan tool.