0312548 JOHNSON COVER, Molding strip, rear

Table 1
Diagnostic Codes
Code Description Conditions Present Comments
157–1 Rail Pressure is Low (Only applies to C3.8 Tier 4 Interim / Stage IIIB)
Injection Fuel Quantity is 0mm3/st or more and the difference between current target and previous target value is 50 mm3/st or lower during normal pump operation.
Injector and Injection drive circuit are normal.
During discharge value is high.
Differential pressure error (target value-actual value of rail pressure) occurs for 5 seconds or more.
Engine derated 50%.
Speed limitation (Accelerator limited 50%).
EGR Stop.
Warning Level 2
1239-1 Fuel Leak (in High-Pressure Fuel System)
Battery Voltage is normal
Sensor Supply Voltage is normal
Rail Pressure Sensor is normal
Supply Pump (SCV) is normal
Injector and Injector Drives circuits are normal
No DTC of 633-7 Pressure Limiter Emergency Open
No DTC of 157-0 High Rail Pressure
No DTC of 1239-1 Fuel Leak in High-Pressure Fuel System
Fuel leak is judged based on the difference between:
The flow volume calculated from the difference of rail pressure (decrease)
Total volume of injection and leakage
Engine Derated
EGR stop
Intake throttle 100 percent open
Warning Level 3
Probable Causes
Codes
Associated codes
Active codes and logged codesHigh-Pressure Fuel System
High-pressure fuel system
Fuel rail pressure sensorTroubleshooting 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-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 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 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.
Fuel 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
(Does not apply to C3.8 Tier 4 Final / Stage IV)
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 suction control valve current in Cat ET
(Does not apply to C3.8 Tier 4 Final / Stage IV)
1800 mA at Low Idle
1600 mA at High Idle
1400 mA at acceleration
Result: If OK proceed to Test Step 6.
Result: If NOT OK replace the suction control valve.
6. Check the pressure limiter
A. Touch the drain hose. The drain hose should be warm from fuel flowing through it.
Pressure Limiter
Result: The drain hose is warm. Replace the common rail manifold since the pressure limiter is not serviceable.
Result: The drain hose is cold. Proceed to Test Step 7.
7. Check the engine oil for fuel
Engine Oil
Result: Fuel is present in the oil. Refer to Troubleshooting, "Oil Contains Fuel".
Result: Oil does not contain fuel.
STOP
Complete the procedure in the order in which the steps are listed.Results:
The procedure corrected the issue - STOP.
The procedure did not correct the issue.Repair: Contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).