Use this procedure if an engine shutdown occurs and the fault indicator for overspeed is flashing.
Test Step 1. Inspect Electrical Connectors and Wiring
- Turn the main disconnect switch to the OFF position.
- Thoroughly inspect all of the connectors that are associated with the circuit.
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 harness and connectors appear to be OK. Proceed to Test Step 2.
- Not OK - There is a problem with 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.Verify that the repair eliminates the problem.
STOP
Test Step 2. Check the Status Control Module (SCM)
- Turn the main disconnect switch to the ON position.
- Turn the Engine Control Switch (ECS) to the OFF/RESET position.
Expected Result:
The fault indicator resets.
Results:
- OK - The fault indicator resets. Verify that there are no existing overspeed conditions. Proceed to Test Step 3.
- OK - The fault indicator does not reset.
Repair: Proceed to Troubleshooting, "Fault Indicator Does Not Reset".
STOP
Test Step 3. Check the Overspeed Setpoint
- Turn the ECS to the START position.
- Start the engine. Run the engine normally.
Expected Result:
The engine starts. The engine runs normally.
Results:
- OK - The engine starts. The engine runs normally. The overspeed setpoint is correct.
Repair: Activate the overspeed verify switch on the back of the SCM and increase the engine speed until a shutdown occurs.If the shutdown occurs at 75 percent of the overspeed setpoint, the overspeed function is OK. Troubleshoot the engine governor.If the shutdown speed is incorrect, proceed to Testing and Adjusting, "Speed Sensor - Adjust". If the speed sensor is OK, replace the SCM.
STOP
- Not OK - The engine starts but the engine overspeeds.
Repair: If the overspeed occurred above the overspeed setpoint, troubleshoot the engine governor.If the overspeed did not occur above the setpoint, proceed to Testing and Adjusting, "Speed Sensor - Adjust". If the speed sensor is OK, replace the SCM.
STOP
- Not OK - The engine did not start and the engine did not run normally.
Repair: The overspeed setpoint is below specifications. Proceed to Testing and Adjusting, "Setpoint Programming".
STOP