**Possible Causes**
• Diagnostic Codes
• Engine Accessories
• Power Mode Control (If Equipped)
• Fuel Supply
• Low Compression (Cylinder Pressure)
• Electronic Unit Injectors
**Recommended Actions**
Note: The steps below are listed in order of probability. Complete these steps in sequence.
**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 for any active or logged diagnostic codes.
**Result:** Codes are active or logged.
**Repair:** Diagnose and resolve all codes before proceeding with this procedure.
**Result:** No codes are active or logged. Proceed to Test Step 2.
**2. Engine Accessories**
A. Inspect all engine accessories for faults that may be imposing an excessive load on the engine.
**Result:** An engine accessory is creating an excessive load.
**Repair:** Repair or replace the engine accessory. **Result:
** No engine accessory is creating an excessive load. Proceed to Test Step 3.
**3. Power Mode Control (If Equipped)**
A. Check the Power Mode Control system using either the Cat Data Link or the CAN Data Link, and then perform the appropriate tests. Refer to *Troubleshooting*, “Data Link – Test” or *Troubleshooting*, “CAN Data Link – Test.”
B. Inspect the engine wiring harness for defects. Refer to *Troubleshooting*, “Electrical Connectors – Inspect.”
**Result:** A fault exists in the data link.
**Repair:** Repair the data link as necessary.
**Result:** A fault exists in the wiring.
**Repair:** Repair or replace the wiring as necessary.
**Result:** The data link and wiring are normal. Proceed to Test Step 4.
**4. Fuel Supply**
A. Ensure that the fuel tank cap vent is not clogged with debris.
B. Ensure that the fuel supply valve (if equipped) is in the fully open position.
C. If the temperature is below 0 °C (32 °F), check the fuel for solidification (waxing).
D. Check the fuel pre-filter / water separator for the presence of water.
E. Check the fuel supply line for blockages.
F. Replace the in-line fuel filter located upstream of the Electric
Fuel Priming Pump (EFLP).
Fuel Priming Pump (EFLP).
G. Check if the EFLP is functioning correctly.
H. Replace the fuel pre-filter and the fuel fine filter.
I. Check if the diesel fuel is contaminated. Refer to *Systems Operation, Testing and Adjusting*, “Fuel Quality – Test”.
J. Check the fuel system for the presence of air. Refer to *Systems
Operation, Testing and Adjusting*, “Air in Fuel – Test”.
Result: The fuel cap vent is blocked.
Repair: Install a replacement fuel cap.
Result: The fuel contains solidified wax.
Repair: Replace the fuel with the correct specification suitable for
the ambient conditions.
Result: The fuel supply line is blocked.
Repair: Replace any damaged or blocked fuel lines.
The EFLP may be malfunctioning. Refer to *Troubleshooting*, “Fuel Priming Pump – Test”.
Replace the fuel pre-filter and the fuel fine filter. Refer to the *Operation and Maintenance Manual* for more 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 the fuel pre-filter and the fuel fine filter. Refer to the *Operation and Maintenance Manual* for more information.
Fill the fuel system with the correct specification of fuel. Refer to *Systems Operation, Testing and Adjusting*, “Fuel System – Prime”. Result: Fuel supply is normal.
Proceed to Test Step 5.
5. Low Compression (Cylinder Pressure)
A. Perform a compression test. Refer to *Systems Operation, Testing and Adjusting*, “Compression – Test”.
Result: The results of the compression test are outside of technical specifications. Investigate the cause and resolve any faults.
Note: Possible causes for low compression pressure are listed below:
below:
· Loose glow plug
· Piston failure · Piston ring failure
· Cylinder bore wear · Valve wear
· Cylinder head gasket failure
· Cylinder head damage
Result: The compression test results are normal. Proceed to Test Step 6.
6. Electronic Unit Injectors
A. Use the electronic service tool to perform an automated “Cylinder Cutout Test.”
Note: If the compression test performed in Test Step 5 met expectations, the “Cylinder Cutout Test” will identify any faulty injectors.
Result: A faulty injector is indicated.
Repair: Remove the faulty electronic unit injector. Refer to
Disassembly and Assembly, “Electronic Unit Injector – Remove.” Install a new electronic unit injector. Refer to Disassembly and Assembly, “Electronic Unit Injector – Install.”
Repeat the automated “Cylinder Cutout Test.” If the fault persists, 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 normal. Contact the Dealer Solution Network (DSN).
