Originally Posted by Meles

I've been working on mine. This isn't quite right. According to alldata, a relay N17/3 is actuated for for about 3 seconds (verified) after the engine is switched off and operates the key-operated engine stop switchover valve (Y9/1). A vacuum of about 500 mbar is present at this valve which when actuated/switched-over operates the the shutoff actuator pneumatically moving the control rod into the stop position.