Passat L4-1984cc 2.0L DOHC (1991)
Fuel Pump Relay: Description and Operation
Fuse / Relay Locations
The Fuel Pump Relay is located in relay position #12 of the main fuse/relay panel (see diagram). The fuse/relay panel is underneath the left side of the
instrument panel on the drivers side of the car.
NOTE: Some vehicles are equipped with a knee bolster to prevent knee injury in the event of an accident. The knee bolster runs along the entire length
of the lower dash. To properly access the fuse/relay panel for servicing, the knee bolster must be removed from in front of the fuse/relay panel.
The Fuel Pump relay receives battery power to energize from the ignition switch and is grounded by the CIS-E Motronic Control Unit. The switched
battery power that flows through the relay comes from the battery source terminal of the fuse box. The switched battery power flows through the relay to
the transfer and main fuel pumps as well as the oxygen sensor heating element. When the ignition is turned ON the Fuel Pump Relay is energized for
only 1 or 2 seconds then the CIS-E Motronic control unit shuts off the relay by removing the ground and de-energizing the relay. When the ignition
switch is turned to the START position the Fuel Pump Relay again comes on for 1 or 2 seconds only. The Fuel Pump Relay is kept energized after the
CIS-E Motronic control unit receives an rpm signal from the ignition system, this rpm signal confirms that the engine is running above 225 rpm. The
purpose of this feature is to prevent flooding while starting, and to stop the fuel pumps in the event of an accident and fire.
