200 Quattro 20V Sedan L5-2226cc 2.22L DOHC Turbo (3B) (1991)
Fuel Pump Relay: Description and Operation
Fuel Pump Relay Socket Terminal ID
The fuel pump relay, located in the fuse/relay panel (in the plenum just ahead of the base of the windshield, under the hood), provides electrical power to
the fuel pump and other systems when energized. ECU energizes the fuel pump relay for approx. 5 seconds when the ignition is turned ON, by grounding
terminal 47/T of the relay. After this time, the relay is de-energized, and the ECU waits for a "cranking" signal before it will again energize the relay.
Once the engine is started, the relay will stay energized as long as the engine is running. If the engine dies, the ECU will turn the relay OFF after 5
seconds and wait for a "cranking" signal before it will energize the relay again.
On some vehicles, computer self diagnostics and output check modes can be accessed by inserting a fuse into the fuse socket on top of the fuel pump
relay. For specific procedures for entering the different self diagnostic modes, refer to COMPUTERIZED ENGINE CONTROLS.