GOVERNOR ASSEM. 4N3926 - Caterpillar

Table 1
Diagnostic Trouble Codes for Excessive Soot Load    
J1939 Code and Description    Information that Relates to the Code    
3719-16 High Diesel Particulate Filter #1 Soot Loading - Level 2     The estimated soot load is high. The ECM shuts down the engine when this code becomes active for the first time. The engine can be started and operated. Engine power is gradually derated as the soot load increases.    
3719-0 High Diesel Particulate Filter #1 Soot Loading - Level 3     The estimated soot load is very high. Engine operation is limited to 30 second intervals when the electronic service tool is not communicating with the ECM.    
3715-31 Diesel Particulate Filter Active Regeneration Inhibited Due to Permanent System Lockout - Level 3     The estimated soot load is very high. The engine may not operate properly. Factory passwords are required in order to clear this code.    
Follow the troubleshooting procedure in order to determine the root cause of the problem.    Troubleshooting Procedure
Perform this test step only when a 3715-31 code is displayed. The 3715-31 code indicates that the engine has continued to run after repeated warnings and engine shutdowns.
Replace the DPF. Refer to Disassembly and Assembly, "Diesel Particulate Filter - Remove" and Disassembly and Assembly, "Diesel Particulate Filter - Install" for the correct procedure.
Connect the electronic service tool to the diagnostic connector. Check for diagnostic codes that relate to the Clean Emissions Module (CEM). Refer to Table 2. Troubleshoot any codes that are present before continuing with this procedure.
Table 2
Associated Codes    
J1939 Suspect Parameter Number (SPN)    Failure Mode Identifier (FMI)    
3703     31    
3750     31    
3711     31    
3473     31    
3474     31    
3714     31    Troubleshoot the systems in the order that is listed above if there are diagnostic codes for more than one of the systems. Use the electronic service tool to perform a service regeneration after the successful completion of the diagnostic procedures.
If there are no associated codes, proceed to Test Step 3.
Illustration 1 g02626300
Typical view of the CEM (1) Diesel Particulate Filter (DPF) (2) Soot antennas (3) Diesel Oxidation Catalyst (DOC) (4) DPF inlet pressure sensor (5) Nozzle heater relay (6) ARD combustion head
Illustration 2 g02232033
Measuring the current through the ARD nozzle heater (7) ARD combustion head (8) Metal part of heater wire (9) Insulated part of heater wire
Use the following procedure to check the ARD nozzle heater:
Verify that the engine is off.
Connect a suitable clamp-ammeter around the insulated part of the heater wire (9). Make sure that the jaws of the ammeter are away from the metal part of the heater wire (8) .
Establish communication between the electronic service tool and the ECM. Refer to Troubleshooting, "Electronic Service Tools" for the proper procedure.
Start the engine. Use the electronic service tool to activate the "ARD Nozzle Heater Test".
Check that the ammeter reads at least 3.5 Amps.
Disable the "ARD Nozzle Heater Test". Stop the engine. Remove the clamp-ammeter.
Disconnect the electronic