KIT-SEAL 3937949 - Caterpillar

System Operation Description:The Electronic Control Module (ECM) has the ability to stop the engine by shutting off the inlet air supply in an emergency situation. The ECM activates a relay which energizes the air shutoff solenoid. The solenoid trips the air shutoff valve.There are two conditions which can cause the ECM to activate the air shutoff relay. The first condition occurs when the ECM detects an engine overspeed. The relay will be energized until the ECM detects an engine speed of 0 rpm. The second condition occurs when a test of the air shutoff relay is made. The overspeed verify switch is activated. When the engine speed reaches 75 percent of the programmed overspeed setpoint, the ECM will activate the air shutoff relay. Again, this is used for testing purposes.The air shutoff valve must be manually reset to the OPEN position.Verify that the air shutoff system has been installed. Verify that the parameter for "Air Shutoff" has been programmed to "ON" on the configuration screen of the CaterpillarElectronic Technician (ET). If the "Air Shutoff" is not programmed, Cat ET will display "Disabled" on the status screen.
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Schematic for the air shutoff system
The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Verify that the air shutoff valves are set to the Open position.
Thoroughly inspect the J1/P1 ECM connector and the P61 customer connector. Refer to Troubleshooting, "Electrical Connectors - Inspect".
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P1 terminals that are associated with the air shutoff system (P1-11) Air shutoff solenoid (P1-54) Overspeed verify switch (P1-67) Solenoid common
Illustration 3 g01123348
J61/P61 terminals that are associated with the air shutoff system (4) Air shutoff solenoid (5) Solenoid common (40) Overspeed verify switch
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the air shutoff system.
Check the allen head screw on the ECM connectors and the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points from the air shutoff solenoid to the ECM.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The connectors and wiring are OK. Proceed to Test Step 2.
Not OK - The connectors and/or wiring are not OK.Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly connected. Verify that the problem is resolved.STOPTest Step 2. Test for Voltage from the Normally Open Contacts of the Air Shutoff Relay
Turn the keyswitch to the OFF position.
Remove the wire from the normally open contacts of the air shutoff relay that goes to the air shutoff solenoid.
Connect a