C7.1 Engines Caterpillar

DEF Temperature Is Low

Usage:

C7.1 881

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Table 1
Diagnostic Trouble Codes for DEF Tank Temperature Is Low
J1939 Code	CDL Code	Code Description (code descriptions may vary)	Comments
3031-7	E1441 (2)	Aftertreatment #1 DEF Tank Temperature : Not Responding Properly	The DCU detects that the DEF tank temperature is not responding properly. The code is logged.
3031-18	E1398 (2)	Aftertreatment #1 DEF Tank Temperature : Low - moderate severity (2)	The DCU detects that the Diesel Exhaust Fluid (DEF) tank temperature is lower than expected.
3363-7	3126-7	Aftertreatment #1 DEF Tank Heater : Not Responding Properly	The DCU detects that the DEF tank temperature is not responding properly during a heating cycle. The code is logged.
5798-7	E1427 (1)	Aftertreatment #1 DEF Dosing Unit Heater Temperature : Not Responding Properly	The DCU detects that the DEF pump temperature sensor is not responding properly. The code is logged.
Follow the troubleshooting procedure to identify the root cause of the problem.

The E1441 (2) or 3031-7 code will be logged when the engine is running, the Diesel Exhaust Fluid (DEF) tank temperature is colder than −8° C (17.6° F) and the DEF tank temperature started to rise, but has fallen back below −8° C (17.6° F).

The E1427 (1) or 5798-7 code will be logged when the engine is running, the DEF tank temperature is warmer than −8° C (17.6° F), the DEF tank temperature has increased, but the DEF pump temperature has not changed.

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Table 2
Associated Diagnostic Trouble Codes
J1939 Code	CDL Code
3363-5	3126-5
3363-6	3126-6
4354-5	3110-5
4354-6	3110-6
4355-5	3111-5
4355-6	3111-6
4356-5	3112-5
4356-6	3112-6
5491-5	3822-5
5491-6	3822-6

Complete the procedure in the order in which the steps are listed.

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Table 3
Troubleshooting Test Steps	Values	Results
1. Check for Associated Diagnostic Trouble Codes A. Download the "Warranty Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes. B. Determine if an associated diagnostic code is present.	Diagnostic trouble codes	Result: An associated diagnostic trouble code is not present. Proceed to Test Step 2. Result: An associated diagnostic trouble code is present. Repair: Troubleshoot the associated code.
2. Check the Coolant Level of the Engine A. Determine if the engine coolant level is full.	Coolant level	Result: The coolant level is full. Proceed to Test Step 3. Result:The coolant level is not full. Repair: Add coolant to the system. Determine the cause of low coolant. Refer to Troubleshooting, "Coolant Level Is Low" for additional information. Proceed to Test Step 3.
3. Check for Coolant Leaks A. Check the entire engine cooling system for signs of coolant leaks. B. Inspect the coolant supply and return lines to the Pump Electronic Tank Unit (PETU) for leaks or damage that may cause restrictions.	Leaks	Result: No leaks were detected. Proceed to Test Step 4. Result: There were leaks or damaged lines detected. Repair: Repair the leaks or damaged lines and refill the coolant system. Proceed to Test Step 4.

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Illustration 1	g03767578
Typical Pump, Electronics, and Tank Unit (PETU) (1) DEF tank header electrical connector (2) DEF tank header

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Table 4
Troubleshooting Test Steps	Values	Results
4. Check the Electrical Connection at the DEF Tank Header A. Inspect electrical connector (1) to DEF tank header (2). Refer to Troubleshooting, "Electrical Connectors - Inspect" for further information. Look for corrosion or loose wires.	Electrical connections	Result: The electrical connections are free of corrosion and are not loose. Proceed to Test Step 5. Result: The electrical connections are corroded and/or are loose. Repair: Make the necessary repairs to the connector. Proceed to Test Step 5.
5. Check the Engine Coolant Temperature A. Start the engine. Allow the engine to warm to normal operating temperature. B. Connect to the electronic service tool. C. Select the "Status Parameters" tab. D. Check the coolant temperature. The temperature should be greater than 50° C (122° F).	Coolant temperature	Result: The coolant temperature is greater than 50° C (122° F). Proceed to Test Step 6. Result: The coolant temperature is not greater than 50° C (122° F). Refer to Troubleshooting, "Coolant Temperature Is Low" for troubleshooting information.

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Illustration 2	g03767596
(3) Coolant diverter valve

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Table 5
Troubleshooting Test Steps	Values	Results
6. Check the DEF Coolant Diverter Valve Solenoid Operation A. Turn the keyswitch to the ON position. B. Start the engine. C. Connect to the electronic service tool. D. Connect to the Dosing Control Unit (DCU). E. Set the status of the coolant diverter valve to open using the "DEF Coolant Diverter Valve Solenoid Override" for 20 minutes. F. Monitor the "DEF Tank Temperature" and make sure that there is an increase of at least 3° C (5.4° F). Note: The DEF tank temperature must be within 5° C (9° F) of ambient air temperature prior to performing this override.	Temperature rise	Result: The DEF tank temperature increased. Proceed to Test Step 7. Result: The DEF tank temperature did not increase. Repair: A failed coolant diverter valve has been detected. Replace the coolant diverter valve. Proceed to Test Step 7.
7. Check the DEF Coolant Diverter Valve Solenoid Operation A. Turn the keyswitch to the ON position. B. Start the engine. C. Connect to Cat ET. D. Connect to the "Diesel Exhaust Fluid Controller #1" E. Set the status of the coolant diverter valve to open using the "DEF Coolant Diverter Valve Solenoid Override" for 20 minutes. F. Monitor the "DEF Tank Temperature" and make sure that there is an increase of at least 3° C (5.4° F). The DEF tank temperature must be within 5° C (9° F) of ambient air temperature prior to performing this override.	Temperature rise	Result: The DEF tank temperature increased. Return the unit to service. Result: The DEF tank temperature did not increase. Repair: A failed DEF tank temperature sensor has been detected. Replace the DEF tank header assembly. Repeat the "DEF Coolant Diverter Valve Solenoid Override" for 20 minutes. If there is a temperature rise in the DEF fluid, return the unit to service. If the fault is still present, contact the Dealer Solutions Network (DSN).