7033 Mercruiser LOCKWASHER, FAN AND PULLEY NUT

The 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 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.
Table 2
Associated Diagnostic Trouble Codes
J1939 Code
3363-5
3363-6
4354-5
4354-6
4355-5
4355-6
4356-5
4356-6 Complete the procedure in the order in which the steps are listed.
Table 3
Troubleshooting Test Steps Values Results
1. Check for Associated Diagnostic Trouble Codes
A. Connect the electronic service tool to the engine ECM.
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 DEF tank 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.
4. Check the Electrical Connection at the DEF Tank Header
A. Inspect the electrical connector to the DEF tank header . Refer to Troubleshooting, "Electrical Connectors - Inspect" for further information.
Check 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).
Investigate the cause of low coolant temperature.
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 engine ECM.
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.
Return the unit to service.
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 Temperature Sensor Operation
A. Turn the keyswitch to the ON position.
B. Start the engine.
C. Connect to the electronic service tool.
D. Connect to the engine ECM.
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).