The Engine Control Module (ECM) detects the following conditions:
- The coolant level is very low for more than 20 seconds.
- The "Coolant Level Sensor" parameter is programmed to "4-pin" or "2-wire Float Sensor".
- The engine has been running for at least 30 seconds.
System Response:
The ECM will display "Low" and "DIAG" next to the status for "Engine Coolant Level" on the Caterpillar Electronic Technician (Cat ET). The check engine lamp and the warning lamp will turn on while this code is active.
Note: If a lamp for low coolant level is installed, the lamp for low coolant level will turn on instead of the warning lamp.
Customer passwords are required to clear this diagnostic code.
None
Test Step 1. Check the Coolant Level
- Check the engine coolant level. Refer to the Operation and Maintenance Manual for more information.
Expected Result:
The engine coolant level is normal.
Results:
- OK - The engine coolant level is normal.
Repair: Ensure that the coolant level sensor is properly installed.
STOP
- Not OK - The engine coolant level is low.
Repair: Add coolant to the engine. Refer to the Operation and Maintenance Manual for more information.
Proceed to Test Step 2.
Test Step 2. Check for Leaks in the Cooling System
- Check for leaking engine coolant.
- Check for coolant in the engine oil.
Expected Result:
There are no leaks. There is no coolant in the engine oil.
Results:
- OK - The engine is not losing any engine coolant.
Repair: Ensure that the engine coolant level is normal.Run the engine until the engine reaches normal operating temperatures.Stop the engine and allow the engine to cool.Recheck the engine coolant level. If the coolant level is low, add more engine coolant.
STOP
- Not OK - The engine is leaking engine coolant or there is coolant in the engine oil.
Repair: Repair the leaks.Verify that the repair eliminates the problem.
STOP