ROD AS 1349844 - Caterpillar

Pressurized System: Hot coolant can cause serious burns. To open the cooling system filler cap, stop the engine and wait until the cooling system components are cool. Loosen the cooling system pressure cap slowly in order to relieve the pressure.
Remove the electrical power from the ECM.
After allowing the engine to cool, check the coolant level. Refer to the Operation and Maintenance Manual. Expected Result:The coolant is at the proper level.Results:
OK - The coolant is at the proper level. Proceed to Test Step 4.
Not OK - The coolant level is low.Repair: Add coolant according to the procedure in the Operation and Maintenance Manual.Verify that the repair eliminates the problem. Identify the source of the coolant leak and fix the problem.STOPTest Step 4. Disconnect the Coolant Level Sensor and Monitor the Status of "Coolant Level"
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to electronic troubleshooting Troubleshooting, "Electronic Service Tools".
Disconnect the connector for the coolant level sensor.
Restore the electrical power to the ECM.
Monitor the status of "Coolant Level" on Cat ET.
Remove the electrical power from the ECM. Expected Result:The status changes from "OK" to "Low" when the sensor is disconnected.Results:
OK - The status is "Low" when the sensor is disconnected. Proceed to Test Step 5.
Not OK - The status is "OK" when the sensor is disconnected. Proceed to Test Step 6.Test Step 5. Short the Harness and Monitor the Status of "Coolant Level"
Restore the electrical power to the ECM and monitor the status of "Coolant Level" on Cat ET.
Install a jumper wire between terminals B (Return) and C (Signal) on the harness connector for the coolant level sensor.
Monitor the status of "Coolant Level" on Cat ET while the jumper wire is installed.
Remove the jumper wire.
Remove the electrical power from the ECM. Expected Result:The status changes from "Low" to "OK" when the jumper wire is installed.Results:
OK - The status changes from "Low" to "OK" when the jumper wire is installed. The ECM and the wiring to the coolant level sensor are OK. There may be a problem with the coolant level sensor.Repair: Perform the following procedure:
Pressurized System: Hot coolant can cause serious burns. To open the cooling system filler cap, stop the engine and wait until the cooling system components are cool. Loosen the cooling system pressure cap slowly in order to relieve the pressure.
Drain the coolant below the level of the coolant level sensor.
Restore the electrical power to the ECM and monitor the status of "Coolant Level" on Cat ET.
Remove the electrical power from the ECM. If the status of the "Coolant Level" is "OK", replace the sensor. Verify that the problem is resolved.If the status for the coolant level is "Low", fill the cooling system according to the procedure in the Operation and Maintenance Manual. Return the engine to service.STOP
Not OK - Shorting the harness does not affect the status on Cat ET. Proceed to Test Step 6.Test Step 6. Check the Wiring for an Open Circuit
Remove the electrical power from the ECM.
Disconnect the J1/P1 and