C4.4 and C6.6 Engines Caterpillar

Use this procedure to troubleshoot abnormal fuel rail pressure or use this procedure if any of the following diagnostic trouble codes are active. Refer to Troubleshooting, "Diagnostic Trouble Codes" for information about the codes.

Table 1

Diagnostic Trouble Codes for Fuel Rail Pressure Problem
J1939 Code	CDL Code	Code Description (code descriptions may vary)	Comments
157-15	E396 (1)	Engine Injector Metering Rail #1 Pressure: High - least severe (1)	No other 157-XX or 1797-XX codes are active. 3509-XX or 262-XX codes are not active. 3510-XX or 2131-XX codes are not active. No codes for the high-pressure fuel pump or the injectors are active. The fuel rail pressure is above an acceptable level. The code is logged. Engine power is derated.
157-16	E396 (2)	Engine Injector Metering Rail #1 Pressure: High - moderate severity (2)	No other 157-XX or 1797-XX codes are active. 3509-XX or 262-XX codes are not active. 3510-XX or 2131-XX codes are not active. No codes for the high-pressure fuel pump or the injectors are active. The fuel rail pressure is above an acceptable level. The code is logged. Engine power is derated.
157-17	E398 (1)	Engine Injector Metering Rail #1 Pressure: Low - least severe (1)	No other 157-XX or 1797-XX codes are active. 3509-XX or 262-XX codes are not active. 3510-XX or 2131-XX codes are not active. No codes for the high-pressure fuel pump or the injectors are active. The fuel rail pressure is below an acceptable level. The code is logged. Engine power is derated.
157-18	E398 (2)	Engine Injector Metering Rail #1 Pressure: Low - moderate severity (2)	No other 157-XX or 1797-XX codes are active. 3509-XX or 262-XX codes are not active. 3510-XX or 2131-XX codes are not active. No codes for the high-pressure fuel pump or the injectors are active. The fuel rail pressure is below an acceptable level. The code is logged. Engine power is derated.
1239-0	E499 (3)	Engine Fuel Leakage 1: High - most severe (3)	3509-XX or 262-XX codes are not active. 3510-XX or 2131-XX codes are not active. There is a probable fuel leak from the high-pressure fuel system. The amount of leakage is a calculated parameter. The code is logged. The engine will stop.
5571-16	E1264 (2)	High Pressure Common Rail Fuel Pressure Relief Valve : Active	3509-XX or 262-XX codes are not active. 3510-XX or 2131-XX codes are not active. The pressure limiting valve in the fuel rail is open. This code is a calculated parameter. The code is logged.
5571-0	E1264 (3)	High Pressure Common Rail Fuel Pressure Relief Valve : Active	3509-XX or 262-XX codes are not active. 3510-XX or 2131-XX codes are not active. The pressure limiting valve in the fuel rail is open. This code is a calculated parameter. The code is logged.

Probable Causes

• Diagnostic codes

• Electrical connectors

• Fuel filters

• Fuel rail pressure sensor

• High fuel rail pressure

• Transfer Pump Inlet Regulator (TPIR)

• Transfer Pump Inlet Regulator (TPIR) return

• Return fuel lines

• Low fuel rail pressure

• Transfer Pump Inlet Regulator (TPIR)

• Transfer Pump Inlet Regulator (TPIR) Return

• Electric Fuel Lift Pump (EFLP)

• Return fuel lines

Recommended Actions

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Contact with high pressure fuel may cause fluid penetration and burn hazards. High pressure fuel spray may cause a fire hazard. Failure to follow these inspection, maintenance and service instructions may cause personal injury or death.

Table 2

Troubleshooting Test Steps	Values	Results
1. Diagnostic Codes A. Connect the electronic service tool to the diagnostic connector. Refer to Troubleshooting, "Electronic Service Tools", if necessary. B. Download the Warranty Report and the Product Status Report with Histograms before diagnosing the fault or clearing any diagnostic codes. Note: The downloaded information will be required by the Dealer Solutions Network (DSN) if diagnostic assistance is needed. C. Determine if a diagnostic is active or recently logged.	Diagnostic codes	Result: One of the codes in Table 1 is present. Proceed to Test Step 2. Result: A code other than the codes in Table 1 is present. Repair: Troubleshoot the code. Refer to the applicable procedure.
2. Electrical Connectors A. Check for the correct installation of the ECM J1/P1 and the J2/P2 connectors. Check for correct installation of the connector on the fuel rail pressure sensor.	Connectors	Result: There are suspect connectors. Repair: Use the electronic service tool to perform the "Wiggle Test". Repair or replace connectors that are suspect. Result: There are no suspect connectors. Proceed to Test Step 3.
3. Fuel Filters A. Replace the in-line fuel filter that is upstream of the electric fuel lift pump (if equipped). Refer to the Operation and Maintenance Manual for further information. If an in-line fuel filter is not installed, replace the fuel strainer on the fuel tank pickup pipe. Refer to the documentation for the machine. B. Replace the primary fuel filter and the secondary fuel filters. Refer to the Operation and Maintenance Manual for further information.	Fuel filters	Result: The filters have been replaced and the fault is eliminated. Return the unit to service. Result: The filters have been replaced and the fault is still present. Proceed to Test Step 4.
4. Fuel Rail Pressure Sensor A. Make sure that the engine has been stopped for at least 10 minutes. Use the electronic service tool to check the status of the "Fuel Rail Pressure".	Pressure sensor	Result: The "Fuel Rail Pressure (absolute)" is more than 5,000 kPa (725 psi). Repair: Test the fuel rail pressure sensor. Refer to Troubleshooting, "Sensor Signal (analog, Active) - Test". Use the electronic service tool to perform the "Fuel Rail Pressure Test". If the test fails, replace the fuel rail. Refer to Disassembly and Assembly, "Fuel Manifold (Rail) - Remove and Install". Confirm that the fault has been eliminated. Result: The "Fuel Rail Pressure (absolute)" is less than 5,000 kPa (725 psi). For a high fuel rail pressure symptom, proceed to Test Step 5. For a low fuel rail pressure symptom, proceed to Test Step 10.
5. High Fuel Rail Pressure A. Use the electronic service tool to perform the "High Pressure Fuel Pump Calibration".	Fuel system	Result: Fuel rail pressure is normal after performing the "High Pressure Fuel Pump Calibration". Return the unit to service. Result: Fuel rail pressure is still high after performing the "High Pressure Fuel Pump Calibration". Run the engine for a minimum of 30 minutes. Proceed to Test Step 6.

Illustration 1	g03700009
Transfer Pump Inlet Regulator (TPIR) components on a C4.4 engine (1) Transfer Pump Inlet Regulator (TPIR) (2) TPIR return port

Illustration 2	g06100802
Transfer Pump Inlet Regulator (TPIR) components on a C6.6 engine (1) Transfer Pump Inlet Regulator (TPIR) (2) TPIR return port

Illustration 3	g02485896
Minimum TPIR flow rate in a 12 V system on a C4.4 engine

Illustration 4	g02485897
Minimum TPIR flow rate in a 24 V system on a C4.4 engine

Illustration 5	g02355128
Minimum TPIR flow rate in a 12 V system on a C6.6 engine

Illustration 6	g02355130
Minimum TPIR flow rate in a 24 V system on a C6.6 engine

Table 3

Troubleshooting Test Steps	Values	Results
6. Transfer Pump Inlet Regulator (TPIR) Flow Test Note: When performing the following fuel system tests, the Electric Fuel Lift Pump (EFLP) will only operate for 2 minutes unless the engine is running. If necessary, cycle the keyswitch to reactivate the pump. For a C4.4 engine, refer to Illustration 1. For a C6.6 engine, refer to Illustration 10. A. Disconnect the TPIR return line from the drain port on the TPIR. Install a suitable blanking cap on the open port in the TPIR return line. B. Connect a temporary drain line to the drain port on the TPIR. C. Place the end of the temporary drain line into a suitable calibrated container. D. With the isolator switch in the ON position but the engine not running, use a suitable multimeter to measure the input voltage to the EFLP. Record the reading. E. With the isolator switch in the ON position but the engine not running, measure the fuel flow from the temporary drain line. F. Refer to Illustration 3 through 14 for the minimum acceptable flow rate. G. Remove the temporary drain line from the drain port on the TPIR. Connect the TPIR return line to the TPIR.	TPIR flow rate	Result: The fuel flow is greater than the minimum limit. Proceed to Test Step 8. Result: The fuel flow is less than the minimum limit. Proceed to Test Step 7.

Illustration 7	g02527498
Minimum EFLP flow rate in a 12 V system

Illustration 8	g02527518
Minimum EFLP flow rate in a 24 V system

Table 4

Troubleshooting Test Steps	Values	Results
7. EFLP Flow Test at the Primary Fuel Filter Inlet A. Make sure the keyswitch is in the OFF position. B. Disconnect the fuel inlet connection from the primary fuel filter head. C. Install a suitable blank on the fuel inlet port on the primary fuel filter head. D. Place the open end of the fuel inlet line in a suitable calibrated container. E. With the keyswitch in the ON position, measure the input voltage at the EFLP. Record the result. F. With the keyswitch in the ON position, measure the flow from the fuel inlet line. Record the result. G. Check the recorded voltage and fuel flow on the graph in Illustration 7 or 8.	EFLP flow	Result: The fuel flow is below the minimum value for the recorded voltage. Repair: Replace the EFLP. Refer to Disassembly and Assembly, "Fuel Priming Pump - Remove and Install". Result: The fuel flow is above the minimum value for the recorded voltage. Proceed to Test Step 8.
8. Transfer Pump Inlet Regulator (TPIR) Return Test A. Make sure that the TPIR return line is not blocked or kinked. B. Check that the Electric Fuel Lift Pump (EFLP) is operating correctly.	TPIR return line	Result: The TPIR return line is blocked or kinked. Repair: Clear the TPIR return line or replace the line Confirm that the fault is eliminated. Result: The EFLP is not operating correctly. Refer to Troubleshooting, "Fuel Transfer Pump - Test". Result: The TPIR return line and the EFLP are OK. Proceed to Test Step 9.
9. Check the Return Fuel Lines A. Make sure that the TPIR return line is not blocked or kinked. B. If the TPIR return line is clear, confirm that the Electric Fuel Lift Pump (EFLP) is operating. Make sure that fuel lines between the EFLP and the TPIR are not blocked or kinked.	Return lines	Result: The TPIR return line or the fuel lines between the EFLP and the TPIR are blocked or kinked. Repair: Clear or replace the blocked line. Result: The TPIR return line and the fuel lines between the EFLP and the TPIR are clear. Repair: Replace the EFLP. If the fault is still present, proceed to Test Step 15.
10. Low Fuel Rail Pressure A. Visually check the fuel tank for fuel. Note: The fuel gauge may be faulty. B. Inspect the high-pressure fuel system for leaks. C. Use the electronic service tool to perform the "High Pressure Fuel Pump Calibration". D. If the temperature is below 0 °C (32 °F), check for solidified fuel (wax). E. Check the primary filter/water separator for water in the fuel. F. Check for fuel supply lines that are restricted or not correctly installed. G. Replace the in-line fuel filter that is installed upstream of the Electric Fuel Lift Pump (EFLP). H. Check that the EFLP is operating correctly. I. Replace the primary fuel filter and the secondary fuel filters. Refer to the Operation and Maintenance Manual for further information. J. Check for air in the fuel system and that the fuel system is primed. K. Check the diesel fuel for contamination. Refer to Systems Operation, Testing, and Adjusting, "Fuel Quality - Test". L. Use the electronic service tool to perform the "Fuel Rail Pressure Relief Valve Test". Note: This test will identify excessive leakage through the Pressure Limiting Valve (PLV) in the fuel rail.	Low-pressure fuel system	Result: There is a leak from the high-pressure fuel system. Repair: Rectify any fuel leaks. 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 or not correctly installed. Repair: Install the fuel lines correctly. Replace any damaged or restricted fuel lines. Result: The EFLP is not operating correctly. Repair: Investigate the fault with the EFLP. Refer to Troubleshooting, "Fuel Transfer Pump - Test". 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 primary fuel filter and the secondary fuel filters. Refer to the 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 low-pressure fuel system is OK. Before performing the following fuel system tests, the engine must be run for a minimum of 30 minutes. Proceed to Test Step 11.

Illustration 9	g03700009
Transfer Pump Inlet Regulator (TPIR) components on a C4.4 engine (1) Transfer Pump Inlet Regulator (TPIR) (2) TPIR return port

Illustration 10	g06100802
Transfer Pump Inlet Regulator (TPIR) components on a C6.6 engine (1) Transfer Pump Inlet Regulator (TPIR) (2) TPIR return port

Illustration 11	g02485896
Minimum TPIR flow rate in a 12 V system on a C4.4 engine

Illustration 12	g02485897
Minimum TPIR flow rate in a 24 V system on a C4.4 engine

Illustration 13	g02355128
Minimum TPIR flow rate in a 12 V system on a C6.6 engine

Illustration 14	g02355130
Minimum TPIR flow rate in a 24 V system on a C6.6 engine

Table 5

Troubleshooting Test Steps	Values	Results
11. Transfer Pump Inlet Regulator (TPIR) Flow Test Note: When performing the following fuel system tests, the Electric Fuel Lift Pump (EFLP) will only operate for 2 minutes unless the engine is running. If necessary, cycle the keyswitch to reactivate the pump. For a C4.4 engine, refer to Illustration 9. For a C6.6 engine, refer to Illustration 10. A. Disconnect the TPIR return line from the drain port on the TPIR. Install a suitable blanking cap on the open port in the TPIR return line. B. Connect a temporary drain line to the drain port on the TPIR. C. Place the end of the temporary drain line into a suitable calibrated container. D. With the isolator switch in the ON position but the engine not running, use a suitable multimeter to measure the input voltage to the EFLP. Record the reading. E. With the isolator switch in the ON position but the engine not running, measure the fuel flow from the temporary drain line. F. Refer to Illustration 11 through 14 for the minimum acceptable flow rate. G. Remove the temporary drain line from the drain port on the TPIR. Connect the TPIR return line to the TPIR.	TPIR flow rate	Result: The fuel flow is greater than the minimum limit. Proceed to Test Step 13. Result: The fuel flow is less than the minimum limit. Proceed to Test Step 12.
12. Transfer Pump Inlet Regulator (TPIR) Return Test A. Make sure that the TPIR return line is not blocked or kinked. B. Check that the Electric Fuel Lift Pump (EFLP) is operating correctly.	TPIR return line	Result: The TPIR return line is blocked or kinked. Repair: Clear the TPIR return line or replace the line Confirm that the fault is eliminated. Result: The EFLP is not operating correctly. Repair: Refer to Troubleshooting, "Fuel Transfer Pump - Test". Result: The TPIR return line and the EFLP are OK. Proceed to Test Step 13.

Illustration 15	g02527498
Minimum EFLP flow rate in a 12 V system

Illustration 16	g02527518
Minimum EFLP flow rate in a 24 V system

Table 6

Troubleshooting Test Steps	Values	Results
13. EFLP Flow Test at the Primary Fuel Filter Inlet A. Make sure the keyswitch is in the OFF position. B. Disconnect the fuel inlet connection from the primary fuel filter head. C. Install a suitable blank on the fuel inlet port on the primary fuel filter head. D. Place the open end of the fuel inlet line in a suitable calibrated container. E. With the keyswitch in the ON position, measure the input voltage at the EFLP. Record the result. F. With the keyswitch in the ON position, measure the flow from the fuel inlet line. Record the result. G. Check the recorded voltage and fuel flow on the graph in Illustration 15 or 16.	EFLP flow	Result: The fuel flow is below the minimum value for the recorded voltage. Repair: Replace the EFLP. Refer to Disassembly and Assembly, "Fuel Priming Pump - Remove and Install". Result: The fuel flow is above the minimum value for the recorded voltage. Proceed to Test Step 14.
14. Check the Return Fuel Lines A. Make sure that the TPIR return line is not blocked or kinked. B. If the TPIR return line is clear, confirm that the Electric Fuel Lift Pump (EFLP) is operating. Make sure that fuel lines between the EFLP and the TPIR are not blocked or kinked.	Return lines	Result: The TPIR return line or the fuel lines between the EFLP and the TPIR are blocked or kinked. Repair: Clear or replace the blocked line. Result: The TPIR return line and the fuel lines between the EFLP and the TPIR are clear. Repair: Replace the EFLP. If the fault is still present, proceed to Test Step 15.
15. Create an Electronic Service Tool Snapshot A. Select "Snapshot Viewer" on the electronic service tool. B. Select the event code and then click "View Data" or "View Graph". Select "Temporary Group" and then click "Change". C. Select the following parameters and then click OK. · Engine Fuel Pump Calibration Status · Engine Fuel Pump Current Offset Calibration Value · Desired Engine Speed · Engine Speed · Fuel Control Valve Command Current · Fuel Rail Pressure · Fuel Temperature · Delivered High Pressure Fuel Pump Flow Rate · Delivered Fuel Volume The data can be viewed as a table or a graph. D. Export the data to an Excel spreadsheet.	Return lines	Result: The electronic service tool snapshot was successfully saved as an Excel file. Send the file to the Dealer Solutions Network (DSN) for analysis Result: The electronic service tool snapshot was not successfully saved as an Excel file. Contact the DSN for guidance.