BEARING-THRUST 0686733 - Caterpillar

function is used to provide secondary steering pressure if the primary steering system loses pressure. The ECM monitors the steering pressure switch at all times. If the pressure in the primary steering is low the ECM will activate the pump for the secondary steering. This will happen only if the system is armed.The secondary steering system can be activated two different ways.
If the engine is running the system is activated. The engine speed must be greater than 500 rpm in order to arm the system.
If the machine is moving the system is armed.The thresholds for both of these criteria are set high. This is done in order to make sure that the machine is running if either of the thresholds are met.Once the secondary steering system is armed the secondary steering system will remain active until the power is removed from the ECM.Once the system is armed any loss of the primary steering pressures will cause the secondary system to activate. The system will remain active until the primary steering pressure is regained, or power is removed from the ECM.The ECM determines loss of primary steering pressure through the steering pressure switch. The switch only senses the primary steering pressure and the switch is unaffected by the pressure of the secondary steering system.