BASE AS 4940022 - Caterpillar

Table 1
Event Code
Code and Description Conditions which Generate this Code System Response
E398(1) Low Fuel Rail Pressure The fuel rail pressure is below the trip point pressure for the programmed delay time. The code is logged.
E398(2) Low Fuel Rail Pressure The code is logged.
Engine power is derated. Probable Causes
Diagnostic codes and event codes
Low-pressure fuel system
Leakage in the high-pressure fuel system
Fuel rail pressure sensor
High-pressure fuel pumpRecommended Actions
Diagnostic Codes and Event Codes
Connect Cat ET to the service tool connector. Check for active diagnostic codes and event codes.Look for active diagnostic codes that are related to the sensors for the low-pressure fuel system. Use the appropriate circuit test to troubleshoot any active codes before continuing.Also, look for active event codes that are related to the low-pressure fuel system. Ensure that a low-pressure event has not been logged repeatedly for the low-pressure fuel system. If there is evidence of a problem with the fuel system, repair the low-pressure fuel system before continuing.Low Pressure Fuel System
Use Cat ET to monitor the "Fuel Pressure (absolute)" status parameter while you operate the engine. Monitor the parameter at all engine speeds.The priming pump will stop after the engine is started. Disregard the fuel pressure during cranking. Wait for the priming pump to stop in order to verify operation of the fuel transfer pump.Ensure that the "Fuel Pressure (absolute)" parameter is greater than 250 kPa (36 psi) (gauge) at low engine idle and that the pressure is at least 450 kPa (65 psi) (gauge) with the engine at high engine idle.Note: At rated engine speed and load, the optimum performance and durability of the high-pressure fuel pump is realized if the inlet pressure for the fuel control valve is maintained at 650 kPa (94 psi). If the fuel system has low pressure, refer to Troubleshooting, "Fuel Pressure Is Low" in order to troubleshoot the symptom.Leakage in the High Pressure Fuel System
Check the high-pressure fuel system for leaks:Check for excess fuel leakage in the fuel rail. Refer to Systems Operation/Testing and Adjusting, "Fuel Rail Leakage - Check" for detailed information.Test for excess fuel flow through the injectors. Refer to Systems Operation/Testing and Adjusting, "Injector Bypass Fuel Flow - Test" for detailed information.Fuel Rail Pressure Sensor
With the engine shutdown, use Cat ET to check the status of the "Fuel Rail Pressure (absolute)". After the engine has been shut down for 10 minutes, the "Fuel Rail Pressure (absolute)" will be less than 5,000 kPa (725 psi) (gauge). Note: If the pressure is not less than 5,000 kPa (725