Charging System Components

WARNING: This page is about a different variant/trim than selected.

Starter/Generator Control Module

The starter/generator control module is a serviceable GMLAN device located in the luggage compartment. It is connected to the vehicle's 12 and 110-volt DC power circuits, and it is also joined to the starter/generator by 3-phase AC cables. The starter/generator control module is air-cooled. The hybrid/EV battery pack cooling fan draws air in through ports in the rear package shelf, flows across the Hybid/EV battery pack and cooling fins of the starter/generator control module, then blows the air out of the vehicle through ports in the luggage compartment. The starter/generator control module performs three main functions:

As the power inverter for the starter-generator, the starter/generator control module converts 110-volt DC power into 3-phase AC power to drive the starter-generator as a motor.
The power inverter also rectifies 110-volt AC output power from the starter/generator into the 110-volt DC power used to charge the 110-volt generator battery.
An auxiliary power module contained within the starter/generator control module converts 110-volt DC power into the 12-volt DC power which is used for 12-volt vehicle loads and to charge the underhood 12-volt battery. A serviceable 200 amp fuse located in the auxiliary fuse block protects the vehicle's 12-volt electrical system from excessive current. The starter/generator control module controls the starter/generator, transmission auxiliary oil pump, hill-hold solenoids, and the auxiliary coolant pump. The pumps and solenoids are driven by 12-volt pulse width modulated (PWM) power through vehicle wiring harnesses.

Body Control Module (BCM)

The body control module (BCM) is a GMLAN device. It communicates with the engine control module (ECM) and the instrument panel cluster (IPC) for electrical power management (EPM) operation. The BCM determines the desired voltage set point and monitors a battery current sensor, the battery positive voltage circuit, and estimated battery temperature to determine battery state of charge (SOC).

Battery Current Sensor

The battery current sensor is a serviceable component that is connected to the negative battery cable at the battery. The battery current sensor is a 3-wire hall effect current sensor. The battery current sensor monitors the battery current. It directly inputs to the BCM. It creates a 5-V pulse width modulation (PWM) signal of 128Hz with a duty cycle of 0-100 percent. Normal duty cycle is between 5-95 percent. Between 0-5 percent and 95-100 percent are for diagnostic purposes.

Engine Control Module (ECM)

The ECM receives control decisions based on messages from the BCM.

Instrument Panel Cluster (IPC)

The IPC provides a means of customer notification in case of a failure and a voltmeter. There are 2 means of notification, a charge indicator and a driver information center (DIC) message of SERVICE BATTERY CHARGING SYSTEM.