Fuel Pump Relay: Description and Operation

Fuel-pump relay (R50)
Fuel-Pump Relay

Function
The fuel-pump relay is used to control the fuel pump. When the ignition is switched on, the fuel pump is supplied with current. The fuel-pump relay remains energized as long as the engine is running. When the engine is not running, the relay is switched off with a time delay. The relay is immediately switched to OFF when the engine is shut down and, following a delay time, the ignition key is detected as in position "OFF". The relay is supplied with current directly from the ignition switch and it is activated when the engine control module connects to ground.

A crash sensor is installed between the relay and the ignition switch. If the sensor is triggered in a collision, this switches off the fuel-pump relay. The crash sensor must be reset manually.

Installation location
The fuel-pump relay is located in the passenger compartment fuse box.

Failure
If the fuel pump fails, the engine is stopped due to lack of fuel.
ck of fuel.