Bosch

Throttle Position Switch:

FOR FUEL INJECTION ECU:
The ECU supplies a voltage (at two terminals) to the throttle switch. When the throttle valve is closed (idle position) or in the full load position, the switch grounds the ECU, allowing the current to flow from one of the two terminals. This will indicate the throttle position to the ECU. The throttle position switch is located on the throttle housing.

FOR IGNITION ECU:
The fuel injection ECU supplies a voltage via the ignition ECU to the throttle switch. When the throttle valve is closed (idle position) the switch grounds the ECU, allowing the current to flow from the terminal. This will indicate the throttle position to the ignition ECU. The throttle position switch is located on the throttle housing.