BOOT 1691644 - Caterpillar

Use this procedure in order to troubleshoot low coolant temperature or use this procedure if the following event code is active. Refer to Troubleshooting, "Event Codes" for information about event codes. You must access the engine monitoring system on Caterpillar Electronic Technician (ET) in order to view the current trip points for these codes. For information on the engine monitoring system, refer to Troubleshooting, "Engine Monitoring System".
Table 1
Event Code
Code and Description Conditions which Activate the Code System Response
E199(1) Low Coolant Temperature The temperature of the engine coolant has fallen below the trip point for the programmed delay time. The code is logged.
The alarm output is activated. Probable Causes
Ambient air temperature
Jacket water heater
Coolant temperature sensor and/or circuit
Water temperature regulatorsRecommended Actions
Ambient Air Temperature
Check that the ambient air temperature is within the limits that are recommended for the engine. Refer to Operation and Maintenance Manual, "Cold Weather Starting". Follow the recommendations that are provided.Malfunctioning Jacket Water Heater
Determine if the jacket water heaters are functioning properly.If the jacket water heaters are not functioning properly, determine the cause of the malfunction of the heaters. Perform the necessary repairs.Coolant Temperature Sensor and/or Circuit
Check the status for the "Engine Coolant Temperature" parameter with the Cat ET while the engine is warming to operating temperature. The temperature should rise steadily as the temperature of the engine rises. Ensure that the temperature is reasonable.If the status of the "Engine Coolant Temperature" parameter is not reasonable, troubleshoot the circuit for the engine coolant temperature sensor. Refer to Troubleshooting, "Sensor Signal (Analog, Passive) - Test".Faulty Water Temperature Regulators
The water temperature regulators should not begin to open until jacket water reaches opening temperature for the regulators. Allow the engine to cool and then start the engine. Check the hose at the outlet for the jacket water. If the hose is warm and normal operating temperature is not achieved yet, a regulator may be stuck open.If the water temperature regulators are suspect, check for the proper operation of the regulators. Refer to Systems Operation/Testing and Adjusting, "Testing the Cooling System". Replace the water temperature regulators, if necessary.