Charging System
The PCM-controlled, or Smart Charge charging system determines the optimal voltage setpoint for the charging system and communicates this information to the voltage regulator. The Smart Charge charging system is designed to set a DTC when a charging system fault is present. All of the Diagnostic Trouble Codes (DTCs) can set continuous faults, but not all Diagnostic Trouble Codes (DTCs) set as on-demand faults.
| Diagnostic Trouble Code (DTC) | Key ON Engine OFF (KOEO) | Key ON Engine Running (KOER) | Continuous |
|---|---|---|---|
| P0562 | X | X | X |
| P0563 | - | X Requires vehicle speed above 13 km/h (8 mph). | X |
| P065B | - | X | X |
| P065C | - | X | X |
| P0A3B | - | X | X |
| U012D | X | X | X |
| U042E | - | X | X |
Some of the Parameter Identifications (PIDs) and their associated descriptions used in the charging system diagnosis are listed below:
| PID | Description | Normal Display |
|---|---|---|
| GENMON | Generator Monitor | Constant fluctuating percentage 3%-98% |
| GENCMD | Generator Command | Fluctuating percentage or small intermittent bursts 3%-98% |
| GENVDSD | Generator Voltage Desired | Voltage varies by vehicle needs - May be controlled by an output state control |
| GENFIL | Generator Fault Indicator Lamp | OFF if charging system is OK |
| GENCMD_LF | Generator Command Line Fault | NO FAULT if GENCOM circuit (GENCMD PID) is OK |
| GENMON_HZ | Generator Monitor Frequency | Frequency value |
| VPWR | Module Supply Voltage | Within 0.5 volt of battery voltage |
| RPM | Engine Revolutions Per Minute | Engine Revolutions Per Minute (RPM) - May be controlled by an output state control |
This system uses a dedicated LIN communication circuit. The generator uses this LIN circuit to communicate the desired setpoint from the PCM to the voltage regulator. The generator also uses this LIN circuit to communicate the generator load and error conditions to the PCM.
The PCM simultaneously controls and monitors the generator output. When the current consumption is high or the battery is discharged, the PCM raises engine speed as needed to increase generator output. The generator charges the battery and at the same time supplies power for all required electrical loads. 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 uses a signal from the IAT sensor to adjust the charging voltage according to the battery temperature. The PCM also uses other inputs to control the charging system voltage such as the VSS and engine coolant temperature. The voltage setpoint is calculated by the PCM and communicated to the voltage regulator by the GENCOM circuit based on the needs of the vehicle and the conditions.
The PCM turns off the generator during cranking to reduce the generator load and improve cranking speed. Once the engine starts, the PCM slowly increases generator output to the desired voltage.
The PCM controls the charging system warning indicator by sending a message over the HS-CAN to the IPC. The IPC module turns the charging system warning indicator ON or OFF. The IPC will also send a message to the FCDIM (vehicles without Touch Screen display) or FDIM (vehicles with Touch Screen display) to display CHECK CHARGING SYSTEM. When the ignition is ON and the engine is off, the CHECK CHARGING SYSTEM message may not be displayed. For additional information regarding the IPC module, Refer to: Message Center - System Operation and Component Description . For additional information regarding the FCDIM or FDIM, Refer to the appropriate Information and Entertainment Systems article for the procedure.
Under certain circumstances the charging system may have a concern but still keep the battery charged and the vehicle running. The LIN normally initiates charging from the PCM, but the generator may continue charging when a fault is present on this circuit. If the engine is operated at greater than 2, 000 rpm momentarily, the generator may self-excite or start charging on its own. The charging system warning indicator is illuminated and/or CHECK CHARGING SYSTEM message 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 is operated at greater than 2, 000 rpm momentarily, the generator may again self-excite and again the charging system warning indicator is illuminated and/or CHECK CHARGING SYSTEM message is displayed.