Principles of Operation
PRINCIPLES OF OPERATIONIn the single generator system, with the engine running, voltage is applied through the charging system warning indicator ignition (I) circuit to the voltage regulator. This turns the regulator on, allowing current to flow from the battery sense A circuit to the generator field coil. When the engine is started, the generator begins to generate AC which is internally converted to DC. This current is then supplied to the electrical system through the output terminal (B+) of the generator.
Once the generator begins generating current, a voltage signal is taken from the generator stator and fed back to the regulator through the stator circuit VDC42 (GN). This voltage feedback signal (typically half the battery voltage) is used by the regulator to provide a signal to the PCM. This, in turn, provides a signal over the controller area network (CAN) communication link to the instrument cluster (IC) to turn off the charging system warning lamp. This indicates the charging system is operating properly.
With the system functioning normally, the generator output current is determined by the voltage of the A circuit. This A circuit voltage (battery sense circuit) is compared to a set voltage internal to the regulator, and the regulator controls the generator field current to maintain correct generator output.
The set voltage varies with temperature and is typically higher in cold temperatures than in warm temperatures. This allows for better battery recharge in the winter and reduces the chance of overcharging in the summer.
This is a System 2 charging system, which uses a PCM-controlled I circuit to the generator regulator, circuit CDC09 (YE). System 2 charging systems are virtually identical in design and therefore, share the same diagnostics. The circuit numbers and colors may be different, but the functions are the same. System 2 charging systems may use any type of generator, as the generator type usually depends on the engine packaging and/or output requirements versus cost.