FITTING AS 9D7994 - Caterpillar

Use this procedure to troubleshoot a low coolant temperature. Also, use this procedure if one of the following event codes is active or logged.
Table 1
J1939 Code and Description CDL Code and Description Comments
110-1
Engine Coolant Temperature : Low - most severe (3) E199 (3)
Low Coolant Temperature The code is logged.
110-17
Engine Coolant Temperature : Low - least severe (1) E199 (1)
Low Coolant Temperature The code is logged.
110-18
Engine Coolant Temperature : Low - moderate severity (2) E199 (2)
Low Coolant Temperature The code is logged. Probable Causes
Codes
Light loads
Jacket water heater
Sensor
Connectors and wiring
Temperature regulators
Personal injury can result from hot coolant, steam and alkali.At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns.Remove filler cap slowly to relieve pressure only when engine is stopped and radiator cap is cool enough to touch with your bare hand.Cooling System Conditioner contains alkali. Avoid contact with skin and eyes.
Recommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: A code is active or logged.
Proceed to Test Step 2.
2. Check for Light Loads
A. Consult the operator to determine the usual load factor.
Load
Result: The load factor is OK.
Proceed to Test Step 3.
Result: The load factor is less than 50 percent.
Note: This overcooling is caused by the reduced amount of heat that is produced by the engine during light loads.
Repair: Operate the engine at a load that is greater than 50 percent.
If the problem is not resolved, proceed to Test Step 3.
3. Check for Proper Operation of the Jacket Water Heater
Heater
Result: The jacket water heaters are OK.
Proceed to Test Step 4.
Result: The jacket water heaters are NOT OK.
Repair: Repair or replace damaged jacket water heater.
If the problem is not resolved, proceed to Test Step 4.
4. Check the Coolant Temperature Sensor
Note: The sensor may be indicating an incorrect temperature that is within the normal range of the sensor.
A. Connect Cat ET.
B. Use Cat ET to monitor the following temperature:
- Coolant temperature
Note: The temperature should rise steadily as the engine is warmed.
C. Ensure that the temperature is reasonable.
D. Reference the reading to another temperature indicator when possible. Refer to Testing and Adjusting, "Testing the Cooling System" for additional information.
Sensor
Result: The temperature sensor is OK.
Proceed to Test Step 6.
Result: The temperature sensor is NOT OK.
Proceed to Test Step 5.
5. Inspect the Electrical Connectors and the Wiring
A. Turn the main disconnect switch to the OFF position.
B. Thoroughly inspect the connectors. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information.
C. Perform a 45 N (10 lb) pull test on the connector wires.
D. Check the harness for abrasions and pinch points.
Connectors and Wiring
Result: The connectors and wiring appear to be OK.
Repair: Replace the sensor.
If the problem is not resolved, proceed to Test Step 6.
Result: There is a problem