DIFFERENTIAL GP-NOSPIN 1103799 - Caterpillar

Probable Causes
Diagnostic codes
Event codes
Power supply
Fuel supplyRecommended Actions
Note: If the problem only occurs under certain conditions, test the engine under those conditions. Examples of certain conditions are high engine speed, full load and engine operating temperature. Troubleshooting the symptoms under other conditions can give misleading results.Diagnostic Codes and Event Codes
Certain diagnostic codes and/or event codes may cause poor performance. Connect the Caterpillar Electronic Technician (ET) and check for active codes and for logged codes. Troubleshoot any codes that are present before continuing with this procedure.Power Supply
Inspect the circuit between the Electronic Control Module (ECM) and the batteries. Refer to the Electrical System Schematic. Inspect the wires, the connectors, and the power relay. Refer to Troubleshooting, "Electrical Power Supply Circuit - Test" for more information.
Inspect the circuit between the ECM and the keyswitch. Refer to the Electrical System Schematic. Inspect the wires, the connectors, and the keyswitch. Refer to Troubleshooting, "Electrical Power Supply Circuit - Test" for more information. Fuel Supply
Check the fuel lines for the following problems: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines.
Check the fuel tank for foreign objects which may block the fuel supply.
Check for air in the low pressure fuel supply system if any of the following procedures have been performed:
Replacement of the fuel filters
Service on the low pressure fuel supply circuit
Replacement of unit injectorsNote: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel. Refer to Testing and Adjusting for more information.
Do not crank the engine continuously for more than 30 seconds. Allow the starting motor to cool for two minutes before cranking the engine again.
Purge air from the low pressure fuel supply circuit. Refer to Testing and Adjusting, "Fuel System - Prime" for the correct procedure.
Check fuel quality. In temperatures below 0 °C (32 °F), check for solidified fuel (wax). Refer to Special Publication, SEBD0717, "Diesel Fuels And Your Engine".
Check the fuel pressure after the fuel filter while the engine is being cranked. Refer to Testing and Adjusting for the correct pressure values. If the fuel pressure is low, replace the fuel filters. If the fuel pressure is still low, check the following items: fuel transfer pump, fuel transfer pump coupling and fuel pressure regulating valve. Refer to Testing and Adjusting for more information.