BOLT-SEGMENT 1171617 - Caterpillar

Use this procedure in order to troubleshoot the emergency stop system. Also, use this procedure if the following diagnostic code is active or easily repeated.
Table 1
Diagnostic Codes Table
J1939 Code and Description Conditions which Generate this Code System Response
970-2
Engine Auxiliary Engine Shutdown Switch : Erratic, Intermittent, or Incorrect The two inputs from the emergency stop switch are in the opposite state. The code is logged. The Electronic Control Module (ECM) receives two signals from the emergency stop switch. The signals allow the ECM to determine the status of the emergency stop switch. The ECM will shut down the engine when both of the signals are open. When both of the signals are connected to the −Battery the emergency stop switch is not active, and the engine will run. If two different signals are detected during the powerup, the ECM will determine that one of the signals is incorrect. A diagnostic code will be logged and a diagnostic code will remain active. The engine will continue to run when the ECM detects two different signals. If both of the signals are open, the engine will stop.The customer can install multiple emergency stop switches. When the Engine Control Switch (ECS) is turned to the ON position, the engine will begin the sequence for start-up.When the emergency stop switch is activated, the ECM will stop firing the injectors. The engine will stop. When an emergency stop is received by the ECM, the ECM will activate the output for the solenoid valve that controls the air shutoff valve. When the solenoid valve activates, the air shutoff valve closes removing the intake air to the engine. Manually open the air shutoff valve in order to start the engine.Note: The air shutoff is optional. Set the programmable parameter with Caterpillar Electronic Technician (ET) in order to enable the air shutoff. The 970-31 Engine Auxiliary Engine Shutdown Switch event code will be set when the remote emergency stop switch is activated. This event will prevent engine operation. Electrical power to the ECM must be removed for three seconds in order to clear this event.
Illustration 1 g03321401
Emergency stop schematic
Illustration 2 g03325742
The P1 ECM connector
(P1-19) Air shutoff
Table 2
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Verify that the air shutoff mechanisms are set to the OPEN position.
C. Thoroughly inspect the ECM connectors. Also, inspect the connectors at the air shutoff mechanism that are for the solenoids. Also, inspect the switches for the air shutoff. Refer to Troubleshooting, "Electrical Connectors - Inspect".
D. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the air shutoff system.
E. Check the allen head screw on each ECM connector for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
F. Check the harness and the wiring for abrasion and for pinch points from the air shutoff solenoid to the ECM.
Connectors
Result: The connectors and