Impreza Sedan AWD F4-1820cc 1.8L SOHC (1993)
Ignition Switch: Description and Operation
Ignition Switch (ON)
Ignition "ON" Signal
PURPOSE
The ignition switch "ON" signal informs the ECU that the key is on and power is needed at MPFI components.
OPERATION
When the ECU receives 12vdc from the ignition switch it supplies the ground for the ignition relay. The relay then provides power for the
following components:
^ Mass air flow sensor
^ Canister purge control solenoid
^ Fuel Injectors
^ Air control valve
^ O2 sensor heater
^ FICD solenoid