900 SE Hatchback L4-1985cc 2.0L DOHC Turbo EFI (1997)
Ignition Shut Down Relay (For Antitheft): Description and Operation
Integral with the anti-theft alarm's electronic control module is a "3-circuit breaking" function which takes over control of the following functions when
the alarm is armed. This prevents the engine from being started when the alarm is set off, as follows:
The starter relay (Ignition "ST" +50) receives no operating voltage as +50 is fed to the alarm control module (pin 20) which breaks operating
voltage on pin 8 if an attempt is made to start the car.
The fuel pump relay receives no operating voltage as the alarm control module receives a fuel pump signal on pin 21 from the engine
management system. The alarm control module then breaks operating voltage on pin 9 to the fuel pump relay. (The engine receives no fuel - the
car cannot be push started either.)
The engine management system does not receive +15 as the alarm control module (pin 22) breaks the voltage.
The "3-circuit breaking" function is connected when the rest of the alarm is armed.