COUPLING AS- 5378508 - Caterpillar

Probable Causes
Diagnostic codes
Fuel supply
Intake manifold pressure sensor
Engine idle
Accessory equipmentRecommended Actions
Diagnostic Codes
Check for active diagnostic codes on Caterpillar Electronic Technician (ET). Troubleshoot any active codes before continuing with this procedure.Fuel Supply
Visually check the fuel level. Do not rely on the fuel gauge only. If necessary, add fuel. If the engine has been run out of fuel, it will be necessary to prime the fuel system. Refer to the Systems Operation/Testing and Adjusting, "Fuel System - Prime".
Cold weather adversely affects the characteristics of the fuel. Refer to the Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold weather operation.
Ensure that the fuel supply valve (if equipped) is in the full OPEN position.
Contact with high pressure fuel may cause fluid penetration and burn hazards. High pressure fuel spray may cause a fire hazard. Failure to follow these inspection, maintenance and service instructions may cause personal injury or death.
Do not loosen any high pressure fuel lines when the engine is running. The high pressure in the fuel lines can cause personal injury or death. Wait 60 seconds after the engine has stopped to allow pressure to purge before any service or repair is performed on the engine fuel lines.
Check the fuel lines for the following conditions: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines replace the lines.
Check the fuel tank for debris or foreign objects which may block the fuel supply.
Prime the fuel system if any of the following procedures have been performed:
Replacement of the fuel filters
Service on the fuel supply circuit
Positive testing for air in the fuel system
Replacement of fuel lines
Replacement of fuel transfer pump
Replacement of Fuel Injection PumpRefer to Systems Operation/Testing and Adjusting, "Fuel System - Prime".
Check fuel quality. Refer to Systems Operation/Testing and Adjusting, "Fuel Quality - Test".Air Inlet and Exhaust System
Check the air filter restriction indicator for a plugged filter. If necessary, service the engine. Refer to the Operation and Maintenance Manual.Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Testing and Adjusting.Engine Idle
Check the parameter for the low engine idle (if applicable). Refer to Troubleshooting, "Configuration Parameters".Accessory Equipment
Check all accessory equipment for problems that may create excessive load on the engine. Repair any damaged components or replace any damaged components.