LOCK AS 2260292 - Caterpillar

System Operation Description:The Electronic Control Module (ECM) has the ability to stop the engine by cutting off the air supply in an emergency situation. The ECM activates the air shutoff solenoid which activates the air inlet shutoff valve.There are two conditions which cause the engine control to activate the air shutoff solenoid. The first condition occurs when the operator initiates an emergency shutdown. When the shutdown is recognized, fuel is shut off and the air shutoff solenoid is activated. The second condition is for an engine overspeed. Engine overspeed can be a real overspeed condition. Overspeed can be obtained by using the overspeed verify switch.Regardless of the reason for activation, the main power to the ECM must be turned OFF for three seconds in order to reset the engine control.Note: The Air Shutoff is optional. A programmable parameter needs to be set with the Caterpillar Electronic Technician (ET) in order to enable the air shutoff.Note: Ensure that BOTH of the air shutoffs are manually reset after an Emergency Stop in order to start the engine again.
Illustration 1 g00861631
Typical exampleTest Step 1. Check for Connector Damage.
Prevent sparks near the batteries. Sparks could cause vapors to explode. Do not allow jumper cable ends to contact each other or the engine.
Disconnect the main power at the Battery disconnect switch.
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: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 2.
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. Test the Circuit.
Start the Cat ET.
Connect the main power.
Access the override on the Cat ET. Activate the override for the air shutoff.Expected Result:The air shutoff solenoid should activate. The Cat ET should indicate "ON".Results:
OK - The air shutoff solenoid activates.Repair: There may be an intermittent problem. If the problem is intermittent, perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".STOP
Not OK - The air shutoff solenoid does not activate. Proceed to test step 3.Test Step 3. Check the Voltage at the Air Shutoff Solenoid.
Disconnect the main power.
Disconnect wire G971-BR from the terminal "C" of the air shutoff solenoid.
Connect a voltage test lamp between G971-BR and engine ground.
Connect the main power.
Access the override on the Cat ET. Activate the override for the air shutoff.
Monitor the voltage test lamp.
Disable the override for the air shutoff.Note: This test will cause a