CYLINDER A 5T6521 - Caterpillar

Use this procedure to troubleshoot a problem with low fuel pressure. Also, use this procedure if one of the following event codes is active or logged.
Table 1
J1939 Code and Description CDL Code and Description Comments
5578-14
Engine Fuel Delivery Absolute Pressure : Special Instruction E489 (1)
Intake Valve Actuation Pressure System Failure The prelubrication cycle completed, but the fuel pressure after the secondary filter is lower than expected.
5580-17
Engine Filtered Fuel Delivery Absolute Pressure : Low - least severe (1) E198 (1)
Low Fuel Pressure The fuel pressure after the secondary fuel filter is lower than expected while the engine is running.
5580-18
Engine Filtered Fuel Delivery Absolute Pressure : Low - moderate severity (2) E198 (2)
Low Fuel Pressure The fuel pressure after the secondary fuel filter is lower than expected while the engine is running.
Table 2
Associated Codes
J1939 Code CDL Code Troubleshooting Procedure
1381-17 E2172 (1) Troubleshooting, "Fuel Transfer Pump Inlet Pressure Is Low"
5584-0 E390 (3) Troubleshooting, "Fuel Filter Is Restricted"
5584-15 E390 (1) Troubleshooting, "Fuel Filter Is Restricted"
5584-16 E390 (2) Troubleshooting, "Fuel Filter Is Restricted" Probable Causes
Codes
Fuel level
Leaks
Voltage
Sensor
Low-pressure regulator
Relief valve
Back-pressure regulator
Bypass valve
Starting priority valveRecommended Actions
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: A code is active or logged.
Proceed to Test Step 2.
2. Check the Fuel Tank Level
A. Remove electrical power from the engine.
B. Inspect the fuel level to make sure that the tank level is not too low.
Fuel Level
Result: The fuel level is NOT low.
Proceed to Test Step 3.
Result: The fuel level is low.
Repair: Add fuel to the fuel tank.
Proceed to Test Step 14.
3. Check for Fuel Leaks
A. Remove electrical power from the engine.
B. Inspect the low-pressure fuel system for leaks.
C. Check the low-pressure fuel system connections to make sure that the connectors are properly torqued.
D. Check the fuel filter drain plug fittings.
E. Check for air in the fuel. Refer to Testing and Adjusting, "Air in Fuel - Test" for the proper procedure.
Leaks
Result: A fuel leak was found.
Repair: Repair or replace damaged fuel system components.
Proceed to Test Step 14.
Result: There are no fuel leaks.
Proceed to Test Step 4.
4. Check for Power to the Low-Pressure Fuel Supply Pump
A. Turn the keyswitch to OFF.
B. Disconnect the wiring harness from the low-pressure fuel supply pump.
C. Turn the keyswitch to ON.
D. Connect Cat ET.
E. Use Cat ET to perform the following override:
- "Electric Fuel Transfer Pump Relay Override"
F. Measure the voltage between the following pins on the wiring harness connector for the low-pressure fuel supply pump:
- Pin 2 and Pin 3
- Pin 2 and Pin 4
G. Inspect and clean the fuel supply clean.
Voltage
Result: The voltage at the low-pressure fuel supply pump module connector is equal to system voltage.
Proceed to Test Step 5.
Result: The voltage at the low-pressure fuel supply pump module connector is NOT equal to system voltage.
Repair: There is a problem with the power supply circuit between the low-pressure fuel