PUMP & MTG GP-MAIN HYDRAULIC 3699641 - Caterpillar

Probable Causes
Diagnostic codes
Starting aids (if applicable)
Water temperature regulators
Unit injectors
Flash file
Fuel supply
Cooling system
Component wearRecommended Actions
Diagnostic Codes
Check for active diagnostic codes on the Caterpillar Electronic Technician (ET). Troubleshoot any active codes before continuing with this procedure.Starting Aids (If Applicable)
If cold ambient conditions exist, check the operation of starting aids. Refer to the appropriate diagnostic functional test for troubleshooting information.Water Temperature Regulators
Check the water temperature regulators for correct operation. Refer to Systems Operation/Testing and Adjusting.Unit Injectors
Use Cat ET to perform the cylinder cutout test. Try to simulate the conditions for the test that were experienced during operation. Cut out each cylinder individually for approximately one minute in order to help identify a misfiring cylinder. If the specific cylinder is identified, proceed to the diagnostic functional test Troubleshooting, "Injector Solenoid Circuit - Test".Flash File
Verify that the flash file is installed. The flash file that is installed in the Electronic Control Module (ECM) will be displayed on the "Configuration" screen on Cat ET.Fuel Supply
Monitor the exhaust for smoke while the engine is being cranked. If no smoke is present, there may be a problem with the fuel quality or there may be a problem with the fuel supply.
Check the fuel quality. Refer to Systems Operation/Testing and Adjusting.
Check the fuel pressure. Refer to Testing and Adjusting.
Ensure that the fuel system has been primed. Refer to Testing and Adjusting.
Check for fuel supply lines that are restricted.
Cold weather adversely affects the characteristics of the fuel. Refer to the applicable Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold weather operation.
Check for air in the fuel system. Refer to Systems Operation/Testing and Adjusting. Cooling System
Check for an internal coolant leak. Check for coolant in the engine oil, coolant in the cylinders, and coolant in the exhaust system. Refer to Systems Operation/Testing and Adjusting.Component Wear
Check the following components for excessive wear:
Valves
Pistons
Rings
Cylinder liners