Voltage Signal: Description and Operation

Battery Voltage Signal
The fuel injector is driven by its solenoid coil based upon the ECM output signal. There is some delay called as "Ineffective injection time", which doesn't provide fuel, between ECM signal and valve action. As the ineffective injection time depends on the battery voltage, ECM takes voltage information to compensate it in fuel injection time.

Electric Load Signal
This signal is sent from each circuit of head & small (or clearance) lights, heater fan, and rear window defogger. ECM uses it as one of the factors for controlling idle air control valve.