Bosch

Sent by the fuel injection ECU:

PURPOSE
The system relay provides current to the fuel pumps, idle air valve, mass air flow sensor, suppressor relay, oxygen sensor pre-heating resistor and to other ECU controlled functions or components.

LOCATION
Located in center console behind the ash-tray.

OPERATION
The fuel injection ECU controls the relay ground connection. When ground is supplied, the system relay is activated and currant can flow to all the related components. If the ground connection is interrupted, no current can reach the components.