Relays (contd.)
Fuel pump relay
The fuel pump relay is located in the relay holder on
the passenger's side. This relay supplies the fuel
pump and oxygen sensor heating elements with cur-
rent.
The fuel pump relay is controlled via the anti-theft
alarm's control module from pin 56 of the Trionic en-
gine control module. Grounding pin 56 causes the
relay to operate.
If the ignition has been switched off for longer than
15 minutes, the fuel pump relay will operate for 2 se-
conds when the ignition switch is turned to the ON
position. The purpose of this is to build up the fuel
pressure prior to pre-injection, which takes place
when the crankshaft starts to rotate.
The fuel pump relay then operates as soon as the
ECM receives pulses from the crankshaft position
sensor.
Saab 9000
Technical Description 57
I
56
102
589
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