RING 8T7567 - Caterpillar

System Operation Description:The Overspeed Verify Switch provides a way to check the system at 75 percent of the set point. The set point is 118 percent over the rated engine speed. When the engine reaches the set point, an overspeed shutdown is initiated. This action will test the shutoff system. The Overspeed Verify Switch allows you to verify proper operation of the system.
Illustration 1 g00894821
Typical exampleTest Step 1. Check for Connector Damage.
Turn the engine control to the OFF position.
Thoroughly inspect the connectors J1/P1 and J2/P2 of the Electronic Control Module (ECM). Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and pinch points.Expected Result:The connectors and wiring should be free of the following problems: damage, corrosion, abrasion and incorrect attachment.Results:
OK - The wiring and connectors are okay. Proceed to test step 3.
Not OK - The wiring and/or connectors need repair.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 2. Check the Status of the Overspeed Verify Switch on the Caterpillar Electronic Technician (ET).
Start the Cat ET.
Turn the engine control to the ON position.
Select the status screen on the Cat ET.
Toggle the overspeed verify switch to the ON position. Toggle the overspeed verify switch to the OFF position.Expected Result:The status of the overspeed verify switch should change in accordance with the switch position.Results:
OK - The circuit for the overspeed verify switch is working correctly.Repair: The system is working correctly. Reset the system and check for any active diagnostic codes.STOP
Not OK - The status screen is not changing in accordance with the switch position. Proceed to test step 3.Test Step 3. Check the Overspeed Verify Switch.
Turn the engine control to the OFF position.
Remove the wire 150-OR from terminal 2 of the overspeed verify switch.
Connect a voltmeter between terminal 3 and terminal 2 of the overspeed verify switch.
Toggle the overspeed verify switch to the ON position. Toggle the overspeed verify switch to the OFF position. Measure the resistance between the terminals.Expected Result:The resistance should measure more than 20,000 Ohms when the overspeed verify switch is in the OFF position. The resistance should measure less than 10 Ohms when the overspeed verify switch is in the ON position.Results:
OK - The overspeed verify switch is working correctly. Proceed to test step 4.
Not OK - The overspeed verify switch is not working correctly.Repair: Replace the overspeed verify switch. Reconnect all wires and connectors. Verify that the circuit is working properly.STOPTest Step 4. Check the Voltage to the Overspeed Verify Switch.
Connect a voltmeter between the wire 150-OR from terminal 2 of the overspeed verify switch and