COVER AS-TANK 2624071 - Caterpillar

Table 1
Diagnostic Trouble Codes
Code Description Conditions Present Response
1239–1 Engine Fuel Leakage 1: Low - most severe (3)
The deviation between actual rail pressure and desired one is more than 20 Mpa for 1 minute or more.
No DTC of 633-7 Pressure Limiter Emergency Open
No DTC of 157-0 High Rail Pressure
No DTC of 1347-7 SCV (MROP) Stuck
Battery voltage is normal.
Sensor supply voltage is normal.
Rail pressure sensor is normal.
Supply pump (SCV) is normal.
Injector and injector drive circuit are normal.
Engine speed is at least 700 rpm.
Engine derates 50%
Engine acceleration limited to 50%
EGR stops
Intake throttle fully open
Warning Level 3
Engine stops in some cases.
Probable Causes
Codes
Fuel system
Fuel rail pressure sensor
Suction control valve
Pressure limiterTroubleshooting Procedure
Table 2
Troubleshooting Test Steps Values Results
1. Determine the Diagnostic Code
A. Establish communication between Caterpillar Electronic Technician (ET) and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Check for active codes and check for logged codes on Caterpillar Electronic Technician (ET).
C. Check Cat ET for any associated codes. Troubleshoot any active codes before continuing with this procedure.
Diagnostic code
Result: An associated code is active or logged.
Troubleshoot any associated codes before continuing with this procedure.
Result: An associated code is not active or logged.
Proceed to Test Step 2.
2. Check the Fuel System
Refer to Systems Operation/Testing and Adjusting, Fuel System, for additional information.
A. Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only.
B. Ensure that the vent in the fuel cap is not filled with debris.
C. Inspect the fuel system for external leaks.
D. Check that there is no air in the clear primary fuel filter. Refer to Systems Operation/Testing and Adjusting, Low Fuel Pressure System- Test.
E. Change the primary fuel filter and the in-line filter for the fuel transfer pump.
F. Check fuel quality. Refer to Systems Operation/Testing and Adjusting, Fuel Quality - Test, for the proper procedure. Check the fuel tank for debris or foreign objects which may block the fuel supply.
G. Check for the proper operation of the fuel transfer pump. Replace the pre-filter if excessive contamination or if the maintenance interval is exceeded. Refer to Systems Operation/Testing and Adjusting, Low Fuel Pressure System-Test, for test information.
Fuel system
Result: The fuel system is OK.
Proceed to Test Step 3.
Result: The fuel system is NOT OK.
Make the necessary repairs.
3. Check the Fuel Rail Pressure Sensor
Refer to Troubleshooting, Sensor Signal (Analog, Active) - Test, for more information.
Rail Pressure Sensor
Result: The fuel rail pressure sensor is OK.
Proceed to Test Step 4.
Result: The fuel pressure sensor is NOT working properly.
Repair: Replace the fuel rail pressure sensor and verify that the problem has been corrected.
4. Check SCV Resistance
A. Check resistance at the SCV terminals. At 20° C (68° F) the resistance should approximately be 2.1 ohms.
B. With the plug connected to the SCV, check resistance at the ECM connector to check the harness. The resistance should be approximately 2.1 ohms.
SCV Resistance
Result: The SCV resistance and the harness are OK.
Proceed to Test Step 5.
Result: The SCV resistance and/or the harness are NOT OK.
Repair: Replace the SCV and/or the engine harness.
5. Check the pressure limiter
A. Touch