PLATE 3283738 - Caterpillar

Illustration 6 g01132478
Harness connector for the coolant level sensor (A) +8 VDC (B) Return
Measure the voltage between terminals A (+8 VDC) and B (return) at the harness connector for the coolant level sensor.
Remove the electrical power from the ECM.Expected Result:The voltage measurement is 8.0 0.4 VDC.Results:
OK - The voltage measurement is 8.0 0.4 VDC. The supply voltage is reaching the sensor. Proceed to Test Step 3.
Not OK - The voltage measurement is not 8.0 0.4 VDC. The digital sensor supply voltage is not reaching the sensor.Repair: Refer to the diagnostic functional test Troubleshooting, "Digital Sensor Supply Circuit - Test".STOPTest Step 3. Check the Coolant Level
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.
Stop the engine.
After allowing the engine to cool, check the coolant level. Refer to Operation and Maintenance Manual.Note: If the coolant has been changed recently, ensure that the air has been purged from the cooling system. Refer to Systems Operation/Testing and Adjusting.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 to the cooling system.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 sensor connectors.
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.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.
Reconnect the