CONTROLLER AS 4416515 - Caterpillar

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 the Operation and Maintenance Manual for the proper procedure.Note: The coolant level sensor should be completely immersed in coolant.Expected Result:The coolant level is low.Results:
OK - The coolant level was low.Repair: Check the cooling system for leaks. Repair any problems that are found. Refill the cooling system to the proper level. Stop.
Not OK - The coolant level is not low.Repair: There may be a problem with the coolant level sensor. Refer to the diagnostic functional test Troubleshooting, "Coolant Level Sensor Circuit - Test" in order to verify that the coolant level sensor is operating correctly.There may be an intermittent problem. Monitor the operation of the engine and repair any problems.Ensure that any repairs eliminate the problem. Stop.