System Operation
Charging System
System Operation
System Diagram
Network Message Chart
Module Network Input Messages - BCM (Body Control Module)
Module Network Input Messages - IPC (Instrument Panel Cluster)
Module Network Input Messages - PCM (Powertrain Control Module)
Charging System
The smart regenerative charge system primary strategy is stored in the BCM (Body Control Module). The BCM (Body Control Module) receives all of the important information relating to the battery condition from the battery monitoring sensor via the LIN (Local Interconnect Network). The BCM (Body Control Module) calculates and sends the set value needed for the generator charging voltage via the HS-CAN (High Speed Controller Area Network) to the PCM (Powertrain Control Module). The PCM (Powertrain Control Module) then adjusts the value received (if necessary) and sends it to the generator via the LIN (Local Interconnect Network). The charging voltage is adjusted depending on various parameters, such as the current level of engine efficiency. The smallest possible set value for the generator voltage is 12.2 volts, while the maximum charging voltage can be anywhere between 14.5 and 14.9 volts. However, when the battery is in a refresh phase, the voltage may occasionally reach up to 15.2 volts. These refresh phases are required when the battery charge status is 80% over long periods of time, which increases the risk of sulfation in the battery cells.
The PCM (Powertrain Control Module) simultaneously controls and monitors the output of the generator. When the current consumption is high or the battery is discharged, the PCM (Powertrain Control Module) raises engine speed as needed to increase generator output. The generator charges the battery and at the same time supplies power for all of the electrical loads that are required. The battery is more effectively charged with a higher voltage when the battery is cold and a lower voltage when the battery is warm.
The PCM (Powertrain Control Module) turns off the generator during cranking to reduce the generator load and improve cranking speed. Once the engine starts, the PCM (Powertrain Control Module) slowly increases generator output to the desired voltage.
The PCM (Powertrain Control Module) reports any charging system faults and sends a message through the HS-CAN (High Speed Controller Area Network) to the BCM (Body Control Module). The BCM (Body Control Module) then sends a message over the MS-CAN (Medium Speed Controller Area Network) to the IPC (Instrument Panel Cluster), which controls the charging system warning indicator. The status of the PCM (Powertrain Control Module) charging system warning indicator message can be confirmed by viewing the PCM (Powertrain Control Module) Generator Fault Indicator Lamp (GENFIL) PID (Parameter Identification). Any charging system fault detected by the PCM (Powertrain Control Module) results in 1 or more DTCs (Diagnostic Trouble Codes) being set and the GENFIL PID (Parameter Identification) having a status of ON. If equipped with a charging system warning indicator, the IPC (Instrument Panel Cluster) turns the indicator on or off. If equipped with a message center, the IPC (Instrument Panel Cluster) displays the corresponding message to notify the driver of the condition.
Under certain circumstances, the charging system may have a concern but still keeps the battery charged while the vehicle is running. The LIN (Local Interconnect Network) is normally used to initiate charging, but the generator can charge with a fault in this circuit. If the engine operates at more than 2,000 RPM (Revolutions Per Minute) momentarily, the generator self-excites or begins charging on its own. The charging system warning indicator is then illuminated and/or the corresponding message to notify the driver of the condition is displayed and the generator operates in a default mode (approximately 13.5 volts) until the engine is turned off. When the engine is restarted and the engine operates at more than 2,000 RPM (Revolutions Per Minute) momentarily, the generator again self-excites and again the charging system warning indicator is illuminated and/or the corresponding message to notify the driver of the condition is displayed.
The Smart Regenerative Charge charging system is designed to set 1 of 7 DTCs (Diagnostic Trouble Codes) any time a charging system fault is present. All of the DTCs (Diagnostic Trouble Codes) can set as continuous faults, but not all DTCs (Diagnostic Trouble Codes) set as on-demand faults.
1 Requires vehicle speed above 8 mph.
Charging System PIDs (Parameter Identifications)
Battery Monitoring System (BMS)
This vehicle is equipped with a BMS (Battery Monitoring System) which manages battery charging by the generator and monitors the battery state of charge. The BMS (Battery Monitoring System) also utilizes a load shed strategy to help control discharge of the battery and prevent, when possible, an excessively low battery state of charge. The BCM (Body Control Module) monitors the battery state of charge using the battery monitoring sensor attached to the negative battery terminal and cable assembly.
NOTICE: When any vehicle module is being programmed, connect an external battery charger to make sure that 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.
To maintain correct operation of the load shed system, any electrical devices or equipment must be grounded to the chassis ground and not the negative battery terminal. A connection to the negative battery terminal causes an inaccurate measurement of the battery state of charge and incorrect load shed system operation due to the current being used bypassing the battery monitoring sensor.
The battery monitoring sensor has to be recalibrated at regular intervals. This occurs during a rest period or when the battery closed-circuit current is less than 100mA. The rest period must last for at least 3 hours. The timeframe in which a recalibration must take place is 7 days. If the system has been unable to carry out a recalibration within this time then it is impossible to confirm the exact state of charge of the battery. Any devices left attached to the power socket that draw in excess of 100mA (or less depending on other battery loads) will prevent a battery monitoring sensor recalibration.
Engine Off Load Shed
When the ignition is in ACC or ON mode and the BCM (Body Control Module) determines the battery voltage or the battery state of charge has dropped below set levels, a low battery warning message is displayed in the message center as described below. Should the battery voltage or the battery state of charge continue to drop, the audio system is powered down to save the remaining battery charge. This load shed state clears once the vehicle has been started and battery state of charge is allowed to recover.
When the ignition is in the ON mode and if load shed occurs, the message center can display the corresponding message to notify the driver that battery protection actions are active. The audio system shuts down after the message center displays the warning.
If a fault occurs with the battery monitoring sensor or circuit(s), the only engine off load shed strategy that is active is a 45 minute timer. After 45 minutes have elapsed, the audio system turns off. To clear the load shed state, restart the engine.
If the vehicle battery is replaced, carry out the BMS (Battery Monitoring System) Reset using the scan tool. If the BMS (Battery Monitoring System) Reset is not carried out, measurement data collected for the old battery will not be deleted and future state of charge measurements will be inaccurate. For example, if an old battery has a state of charge of 60% and the new battery has a state of charge of 90%, the BCM (Body Control Module) will recognize battery state of charge being 30% lower than it actually is. With the battery state of charge being perceived lower than it actually is causes shedding of loads earlier than is necessary. This also impacts the smart regenerative charge system (REFER to Charging System) by causing the battery to be maintained at a higher state of charge than perceived by the BCM (Body Control Module), reducing fuel economy benefits.
If the vehicle has been jump started, test the battery condition. REFER to Diagnostic Routine A: Battery Condition Test Pinpoint Tests.
For charging the vehicle battery, REFER to Battery Charging .