0323276 JOHNSON BUMPER, Choke plunger

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 the drain hose to feel if the line is 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.
If the above steps are all completed and no issue is found, this code has frequently been to have been caused by lack of fuel to the engine from the low-pressure fuel system or by an engine harness problem in the rail pressure sensor or SCV circuit. If the low-pressure fuel system has been thoroughly checked, then change the engine harness or else contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).