0512832 JOHNSON TERMINAL

Illustration 1 g06486294
Table 1
Troubleshooting Test Steps Values Results
1. Check the Coolant Level
Allow the engine to cool prior to removal of the cooling system pressure cap.
A. Remove electrical power from the ECM.
B. Check the coolant level. Refer to the Operation and Maintenance Manual for the proper procedure to check the coolant level.
Coolant level
Result: The coolant level is OK.
Proceed to Test Step 2.
Result: The coolant level is NOT OK.
Add coolant according to the procedure in the Operation and Maintenance Manual.
There may be a leak in the cooling system. Identify the source of the coolant leak. Repair the leak. Refer to Systems Operation/Testing and Adjusting, "Cooling System" for additional information.
If the problem is not resolved, proceed to Test Step 2.
2. Verify that the "Coolant Level Sensor" Parameter is Programmed Correctly
A. Connect Cat ET to the service tool connector.
B. Establish communication with the ECM.
C. Verify that the "Coolant Level Sensor" parameter is programmed to "Installed".
D. Remove electrical power from the ECM.
Parameter programmed
Result: The "Coolant Level Sensor" parameter is OK.
Proceed to Test Step 3.
Result: The "Coolant Level Sensor" parameter is NOT OK.
Program the "Coolant Level Sensor" parameter to "Installed".
If the problem is not resolved, proceed to Test Step 3.
3. Check the Supply Voltage at the Sensor Connector
A. Disconnect the coolant level sensor at the sensor connector.
B. Restore electrical power to the ECM.
C. Measure the voltage between terminals 1 (sensor supply) and 2 (sensor return) at the harness connector for the coolant level sensor.
D. Remove electrical power from the ECM.
System voltage
Result: The voltage measurement is OK.
The supply voltage is reaching the sensor. Proceed to Test Step 4.
Result: The voltage measurement is NOT OK.
The sensor supply voltage is not reaching the sensor. There is a problem in the circuit for the sensor supply. Repair the wiring between the sensor and the ECM.
If the problem is not resolved, proceed to Test Step 4.
4. Short the Signal Wire to Ground and Monitor the Status for "Coolant Level"
A. Fabricate a jumper wire that is long enough to create a short circuit between two terminals at the coolant level sensor harness connector. Crimp connector pins to each end of the jumper wire.
B. Install the jumper wire between terminals 2 (sensor return) and 3 (sensor signal) on the harness side of the connector for the coolant level sensor.
C. Restore electrical power to the ECM.
D. Monitor the status of "Coolant Level" on Cat ET while the jumper wire is installed. Wait at least 30 seconds for activation of the status indicator.
E. Remove the jumper wire. Connect the harness connector for the coolant level sensor.
The voltage is within 5 VDC of battery voltage
Result: The status changes from "LOW" to "OK" when the jumper wire is installed. The ECM and the wiring harness to the coolant level sensor are OK.
Repair: Replace the coolant level sensor. Verify that the repair eliminates the problem.
Result: The status does not change from "LOW" to "OK" when the jumper wire is installed.
Repair: The problem is between the ECM and the sensor connector. Repair the wiring. Verify that the repair eliminates the problem.