WASHER-THRUST 2004215 - Caterpillar

Conditions Which Generate This Code:The Electronic Control Module (ECM) detects the following conditions:
The engine has been running for at least two minutes.
Engine coolant temperature that has increased above 75 °C (167 °F)
Engine coolant temperature that has decreased below 70 °C (158 °F) for two minutesSystem Response:The event is logged. After the temperature returns above 75 °C (167 °F) the warning due to low coolant temperature will be turned off.
None
There may be a problem with the coolant temperature sensor.
Faulty water temperature regulator
Long idle periods
Very light loadsTest Step 1. Check for Active Diagnostic Codes
Start the Caterpillar Electronic Technician (ET).
Turn the keyswitch to the ON position.
Check for any active diagnostic codes or logged diagnostic codes.Expected Result:No diagnostic codes are present.Results:
OK - No diagnostic codes are present. Proceed to Test Step 2.
Not OK - Diagnostic codes are present.Repair: Repair the diagnostic codes that are present.STOPTest Step 2. Perform a Check of the Cooling System
Perform a check of the cooling system. Test the water temperature regulator for proper operation. A regulator that is stuck open can cause overcooling. Coolant leaks that are around the water temperature regulator can cause overcooling. An example would be a leak in the vent line.Note: Refer to the Systems Operation/Testing and Adjusting manual for information on testing the water temperature regulator.Expected Result:The water temperature regulator is operating correctly.Results:
OK - The water temperature regulator is operating correctly.Repair: Cold ambient temperatures, light loads, or a slow engine speed can cause overcooling. This overcooling is caused by the low heat input of the engine.STOP
Not OK - There is a problem with the water temperature regulator.Repair: Replace the water temperature regulator.STOP