Voltage Signal: Description and Operation

THEORY OF OPERATION:
The PCM monitors battery voltage input to determine fuel injector pulse width and generator field control voltage.

Injector Pulse Width
If voltage is low the PCM will increase pulse width (the period of time that the injector is energized).

Generator Field Voltage
The PCM tries to maintain a system voltage between 12.9 volts and 15.0 volts. The voltage determined by the PCM as the final goal for the charging system is called "control" voltage. This control voltage is determined from the battery temp sensor for ambient sensor and the sensed voltage system voltage at the PCM. The control voltage is compared to the sensed voltage continuously during running.
- If the sensed voltage is less than the control voltage the PCM will supply more ground to the field circuit.
- If the sensed voltage is more than the control voltage the PCM will supply less ground to the field circuit.

GENERATOR FIELD-PCM OUTPUT
The PCM regulates the charging system voltage within a range of 12.9 to 15.0 volts.

BATTERY TEMPERATURE SENSOR-PCM INPUT
The PCM uses the temperature of the battery area to control the charge rate. The signal is used to regulate the system voltage. The system voltage is higher at cold temperatures and is gradually reduced as temperature is increased.