98974M Mariner CLAMP

Illustration 1 g01342179
Typical schematic
Illustration 2 g01248310
A-C2/KJ-C2 connector or KJ-C1/KJ-C8 connector (Terminal 11) Air shutoff
Illustration 3 g01248306
P2 ECM connector (P2-13) Air shutoffTest Step 1. Inspect Electrical Connectors and Wiring
Turn the local/remote switch on the control panel to the OFF/RESET position.
Thoroughly inspect the ECM connectors. Inspect all of the other connectors for the circuit. Refer to 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. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Check the harness and the wiring for abrasion and for pinch points.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. 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 - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.STOPTest Step 2. Test the Air Shutoff System
Turn the local/remote switch on the control panel to the LOCAL position.
Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the "overspeed verify override".
Start the engine.
Monitor the air shutoff solenoid as the engine speed nears the modified setpoint of 975 rpm.Note: As the engine speed exceeds 975 rpm the air shutoff solenoid should activate. The engine should shut down.Expected Result:The air shutoff solenoid activates.Results:
OK - The air shutoff solenoid activated correctly.Repair: The problem may be intermittent. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".STOP
Not OK - The air shutoff solenoid failed to activate. Proceed to Test Step 3.Test Step 3. Check the Voltage to the Air Shutoff Solenoid from the User Interface Panel
Turn the local/remote switch on the control panel to the OFF/RESET position.
Remove wire N757-GY from terminal TB-85 or from terminal AC-C1-11 in the user interface panel. Refer to Illustration 1 in order to identify the configuration of the wiring.
Connect a voltmeter between the wire N757-GY and engine ground.
Turn the local/remote switch on the control panel to the LOCAL position.
Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the "overspeed verify override".
Start the engine.
Monitor the voltage on the voltmeter as the engine speed nears the modified setpoint of 975 rpm.Note: As the engine speed exceeds 975 rpm the voltage should measure approximately 24 VDC for one second.
Turn the local/remote switch on the control panel to the OFF/RESET position.
Reinstall all wires.Expected Result:The voltage measured approximately 24 VDC.Results:
OK - The voltage was OK. The problem appears to be in the wiring between the user interface panel and the air shutoff solenoid.Repair: Repair the wiring or replace the wiring between the user interface panel and the air shutoff solenoid.STOP
Not OK - The voltage was not OK. Proceed to Test Step 4.Test Step 4. Check the Voltage to the User Interface Panel
Remove wire 386-GY from terminal A-C2-11 or from terminal AC-C2-11 in the user interface panel. Refer to Illustration 1 in order to identify the configuration of the wiring.
Connect a voltmeter between terminal A-C2-11 or terminal AC-C2-11 and the engine ground.
Turn the local/remote switch on the control panel to the LOCAL position.
Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the "overspeed verify override".
Start the engine.
Monitor the voltage on the voltmeter as the engine speed nears the modified setpoint of 975 rpm.Note: As the engine speed exceeds 975 rpm the voltage should measure approximately 24 VDC for one second.
Turn the local/remote switch on the control panel to the OFF/RESET position.
Reinstall all wires.Expected Result:The voltage measured approximately 24 VDC.Results:
OK - The voltage was OK. The problem appears to be in the "shutoff driver diode" or in the wiring to the "shutoff driver diode".Repair: Repair the wiring or replace the wiring. If necessary, replace the "shutoff driver diode".STOP
Not OK - The voltage was not OK. Proceed to Test Step 5.Test Step 5. Check the Voltage from the ECM
Fabricate a jumper wire that can be used to replace the wire in the ECM connector for the air shutoff. Crimp a connector socket to one end of the jumper wire.
Remove wire 386-GY from ECM connector P2-13. Refer to Illustration 1 in order to identify the configuration of the wiring.
Install the jumper wire into the terminal location for the air shutoff at the ECM connector.
Connect the ECM connector.
Connect a voltmeter between the wire jumper and engine ground.
Turn the local/remote switch on the control panel to the LOCAL position.
Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the "overspeed verify override".
Start the engine.
Monitor the voltage on the voltmeter as the engine speed nears the modified setpoint of 975 rpm.Note: As the engine speed exceeds 975 rpm the voltage should measure approximately 24 VDC for one second.
Turn the local/remote switch on the control panel to the OFF/RESET position.
Reinstall all wires.Expected Result:The voltage measured approximately 24 VDC.Results:
OK - The voltage was OK. The problem appears to be in the wiring between the ECM connector and the user interface panel.Repair: Repair the wiring or replace the wiring.STOP
Not OK - The voltage was not OK.Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM". Verify that the problem is resolved.STOP