DRIVE GP-ACCESSORY 7N4871 - Caterpillar

Operation Description:The customer's emergency stop switch sends two signals to the Electronic Control Module (ECM). The signals are used to determine if the remote emergency stop switch is active. The remote emergency stop switch is active when the switch is in the open state and the two signals are held high. The remote emergency stop switch is inactive when the switch is in the closed state and the two signals are held low.If the ECM is powering up and one of the signals from the remote emergency stop switch is in a different state from the other signal, the ECM knows that one of the signals is faulty. If one of the signals from the remote emergency stop switch is in a different state from the other signal, the ECM will generate a diagnostic code that remains active until power to the ECM is cycled. The ECM will not allow the crank cycle to begin if the signals are opposite of each other. The ECM will allow the engine to be started manually in this state. The ECM monitors the remote emergency stop signals at all times. If the engine is running and one of the signals from the remote emergency stop switch changes states, the engine will continue to run. The ECM initiates a remote emergency stop shutdown only when both signals are in the open state during engine operation. For safety, the ECM will not allow the starting sequence to begin when the remote emergency stop switch is activated.
Illustration 1 g00808412
Typical remote emergency stop circuitNote: The Engine Control Switch (ECS) is mounted within an instrument panel that is located on the right side of the engine. The ECS is locked into the AUTO position with a pin. The pin must be removed in order to perform this test. After performing this test, ensure that the ECS is placed in the AUTO position and that the locking pin has been reinstalled.Test Step 1. Check for Connector Damage.
Disconnect main power.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. 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:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring should be free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and wiring are okay. Proceed to test step 2.
Not OK - The connectors and/or wiring need repair.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring. Stop.Test Step 2. Check the ON Status of the Remote Emergency Stop Switch.
Turn the circuit breaker for