11752M Mariner THERMOSTAT

Recommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in order.
Table 1
Troubleshooting Test Steps Values Results
1. Diagnostic Codes
A. Establish communication between the electronic service tool and the Electronic Control Module (ECM) . If necessary, refer to Troubleshooting, "Electronic Service Tools".
B. Check if any codes are active or logged.
Diagnostic code
Result: A code is active or logged.
Repair: Troubleshoot any codes before continuing with this procedure.
Result: A code is not active or logged.
Proceed to Test Step 2.
2. Accessory Equipment
A. Check all accessory equipment for faults that may create excessive load on the engine.
Accessories
Result: An engine accessory is creating an excessive load.
Repair: Repair or replace the engine accessory.
Result: An engine accessory is not creating an excessive load.
Proceed to Test Step 3.
3. Power Mode Control (If Equipped)
A. Refer to Troubleshooting, "CAN Data Link - Test".
B. Check the engine wiring harness for defects. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Power mode control
Result: There is a fault in the data link.
Repair: Repair the data link, as necessary.
Result: There is a wiring fault.
Repair: Repair or replace the wiring, as necessary.
Result: The data link and the wiring are OK.
Proceed to Test Step 4.
4. Fuel Supply
A. Ensure that the vent in the fuel cap is not filled with debris.
B. Ensure that the fuel supply valve (if equipped) is in the full OPEN position.
C. If the temperature is below 0 °C (32 °F), check for solidified fuel (wax).
D. Check the primary filter/water separator for water in the fuel.
E. Check for fuel supply lines that are restricted.
F. Replace the in-line fuel filter that is installed upstream of the Electric Priming Pump (EPP).
G. Check that the EPP is operating correctly.
H.Replace any filters and/or screens in the fuel system. Refer to Operation and Maintenance Manual for further information.
I. Check the diesel fuel for contamination. Refer to Systems Operation, Testing, and Adjusting, "Fuel Quality - Test".
J. Check for air in the fuel system. Refer to Systems Operation, Testing, and Adjusting, "Air in Fuel - Test".
Fuel system
Result: The vent in the fuel cap is blocked.
Repair: Install a replacement fuel cap.
Result: The fuel contains solidified wax.
Repair: Replace the fuel with fuel of the correct specification for the ambient conditions.
Result: There are fuel supply lines that are restricted.
Repair: Replace any damaged or restricted fuel lines.
The EFLP is suspect. Refer to Troubleshooting, "Fuel Transfer Pump - Test".
Replace any filters and/or screens in the fuel system. Refer to Operation and Maintenance Manual for further information.
Result: There is air in the fuel system.
Repair: Prime the fuel system. Refer to Systems Operation, Testing, and Adjusting, "Fuel System - Prime".
Result: The diesel fuel is contaminated.
Repair: Drain the fuel tank and the fuel system.
Replace any filters and/or screens in the fuel system. Refer to Operation and Maintenance Manual for further information.
Fill and prime the fuel system with fuel of the correct specification. Refer to Systems Operation, Testing, and Adjusting, "Fuel System - Prime".
Result: The fuel supply is OK.
Proceed to Test Step 5.
5. Low Compression (Cylinder Pressure)
A. Perform a compression test. Refer to Systems Operation, Testing, and Adjusting, "Compression - Test".
Cylinder compression
Result: The results of the compression test are outside the specifications.
Investigate the cause and rectify any faults.
Note: Possible causes of low compression are shown in the following list:
Loose glow plugs
Faulty piston
Faulty piston rings
Worn cylinder bores
Worn valves
Faulty cylinder head gasket
Damaged cylinder head
Result: The results of the compression test are OK.
Proceed to Test Step 6.
6. Electronic Unit Injectors
A. Use the electronic service tool to perform the automatic "Cylinder Cutout Test".
Note: If the compression test that was performed in Test Step 5 was satisfactory, the "Cylinder Cutout Test" will identify any faulty injectors.
Electronic Unit Injectors
Result: A faulty injector is indicated.
Repair: Remove any faulty electronic unit injectors. Refer to Disassembly and Assembly, "Electronic Unit Injector - Remove".
Install new electronic unit injectors. Refer to Disassembly and Assembly, "Electronic Unit Injector - Install".
Repeat the automatic "Cylinder Cutout Test". If the fault is still apparent, remove the replacement electronic unit injector and install the original electronic unit injector. Refer to Disassembly and Assembly, "Electronic Unit Injector - Remove" and Disassembly and Assembly, "Electronic Unit Injector - Install".
Result: All injectors are OK.
Contact the Dealer Solutions Network (DSN).