This condition indicates that the coolant level is low. "Engine Monitoring" must be programmed to "WARNING", "DERATE", or "SHUTDOWN", and the parameter "Coolant Level Sensor" must be programmed to "4-pin" or "2-wire Float Sensor" before this diagnostic code can occur.
Note: This diagnostic code represents an event. This diagnostic code does not represent an electronic system fault.
System Response:
Electronic System Response If the "Engine Monitoring" is programmed to "DERATE" or "SHUTDOWN", the ECM will derate the power and the ECM will limit the vehicle speed due to this diagnostic code.
If "Engine Monitoring" is programmed to "WARNING", the Check Engine Lamp will flash and the Warning Lamp will illuminate continuously.
If "Engine Monitoring" is programmed to "DERATE" or "SHUTDOWN", the Check Engine Lamp and the Warning Lamp will flash.
This diagnostic code requires a Customer Password in order to be cleared.
Service Tool Display or Lamps The Caterpillar Electronic Technician (Cat ET) will display "LOW" and "DIAG" next to "Engine Coolant Level" on the status screen while the diagnostic code is active.
Engine Response If "Engine Monitoring" is programmed to "WARNING" this diagnostic code does not affect engine power.
If "Engine Monitoring" is programmed to "DERATE" or "SHUTDOWN", the vehicle speed is limited to a maximum of 72 km/h (45 mph), and the power is limited. The engine will shut down if conditions exist for a long enough period in the SHUTDOWN mode.
Test Step 1. Check the Level of the Coolant
Visually check the level of the coolant. Ensure that the coolant level switch is fully immersed in the coolant.
Expected Result:
The coolant is at the proper level.
Results:
- OK -
Repair: If a problem with the coolant level sensor is suspected, refer to Troubleshooting, "Coolant Level Sensor Circuit - Test".
Stop.
- Not OK -
Repair: Fill the cooling system with the proper coolant to the correct level. For further information, refer to the Operations and Maintenance Manual.
Stop.