VALVE-GOVERNOR SERVO 1152553 - Caterpillar

System Operation Description:The Electronic Control Module (ECM) has the ability to stop the engine by shutting off the inlet air supply in an emergency situation. The ECM activates the output driver for the emergency shutdown system. The "ASOS" switch energizes the two air shutoff solenoids. The solenoids trip the air shutoff valves.There are two conditions which cause the engine control to activate the output driver for the air shutoff switch. The first condition occurs when the operator activates the customer's emergency stop. When the customer's emergency stop button is activated, the emergency stop inputs U and T to the ECM from the customer connector go high. The ECM will recognize this change. The ECM will energize the output drive for the emergency shutdown system for one second through the diode assembly.The second condition occurs