12V Battery Charging System
The 12V battery is charged by the Direct Current/Direct Current (DC/DC) converter control module. The Battery Monitoring Sensor continuously monitors the battery state of charge condition and provides the BCM with this information. The BCM communicates this information to the PCM over the High Speed Controller Area Network (HS-CAN). The PCM communicates the battery desired setpoint to the Direct Current/Direct Current (DC/DC) converter control module which supplies the necessary charge voltage to the 12V battery. For more information, Refer to: DIRECT CURRENT/DIRECT CURRENT (DC/DC) CONVERTER CONTROL MODULE - SYSTEM OPERATION AND COMPONENT DESCRIPTION .
12V Battery Management System
Note. When any vehicle module is being programmed, connect an external battery charger to make sure the module programming is completed without interruption due to the load shedding feature becoming active. The external battery charger must maintain a system voltage above 13 volts. This may require a charger setting higher than the lowest charge setting. The external battery charger negative connection must be made to an engine or vehicle chassis ground and not the negative battery terminal. If the connection is to the negative battery terminal, load shedding may begin and module programming may be corrupted. After charging has begun, start the engine to clear any load shed states and then turn the engine off and proceed with programming.
Charging and Jump Starting
Do not charge or jump start the vehicle by connecting to the battery negative terminal. Refer to the Owners Guide for more information.
If the vehicle has been jump started, test the battery condition.
Refer to: BATTERY .
If the 12V vehicle battery has been charged by connecting to the battery negative terminal, do not reset the Battery Monitoring System.
Battery Monitoring Sensor
The Battery Monitoring Sensor continuously monitors the condition and the state of charge of the 12V battery and provides the BCM with this information. The Battery Monitoring Sensor also estimates losses in the battery capacity over time. The Battery Monitoring Sensor should only be reset when the battery is replaced. It is urgently recommended that the replacement battery has the exact same specification as the original battery. If it does not, the accuracy of the Battery Monitoring Sensor outputs will be compromised.
The Battery Monitoring Sensor is clamped directly to the negative terminal of the battery and grounds to the vehicle at the chassis ground connection point through the negative battery cable and eyelet. It is part of the negative battery cable and cannot be serviced separately. For more information, Refer to: BATTERY AND CABLES - SYSTEM OPERATION AND COMPONENT DESCRIPTION .
External customer loads must only be connected to the vehicle at the customer battery connection point. If an external customer load is connected at the negative battery post, the Battery Monitoring Sensor accuracy cannot be guaranteed. It is recommended that the Battery Monitoring Sensor pole clamp is not removed unless a battery replacement is required. Should the battery need to be isolated, this should be done by disconnecting the ground eyelet at the chassis ground.
Body Control Module (BCM)
The BCM monitors the Battery Monitoring Sensor and provides the PCM with battery state of charge information. For more information on the BCM
Refer to: MODULE CONTROLLED FUNCTIONS - SYSTEM OPERATION AND COMPONENT DESCRIPTION .
Powertrain Control Module (PCM)
The PCM provides desired voltage set point to the Direct Current/Direct Current (DC/DC) converter control module. For more information on the PCM
Refer to: ELECTRONIC ENGINE CONTROLS - SYSTEM OPERATION AND COMPONENT DESCRIPTION .
Direct Current/Direct Current (DC/DC) converter control module
The Direct Current/Direct Current (DC/DC) converter control module is responsible for maintaining and charging the 12V battery. It is enabled when the high voltage battery contactors have closed, providing high-voltage power to the Direct Current/Direct Current (DC/DC) converter control module. For more information
Refer to: DIRECT CURRENT/DIRECT CURRENT (DC/DC) CONVERTER CONTROL MODULE - SYSTEM OPERATION AND COMPONENT DESCRIPTION .
Possible Sources
- Battery monitoring sensor
- BCM
- Wiring, terminals or connectors