BYPASS AS-FILTER 9T2760 - Caterpillar

Probable Causes
Active engine derate
Cold mode
Throttle signal
Intake manifold (boost) pressure sensor
Atmospheric pressure sensor
Fuel supply
Air inlet and exhaust system
Accessory equipmentRecommended Actions
Active Engine Derate
Connect Caterpillar Electronic Technician (ET) and check for an active derate event. A derate status flag will appear on Cat ET if an active engine derate is occurring. In order to view active events, go to the "Events" menu under "Diagnostics".Cold Mode
Use Cat ET to verify that the engine has exited cold mode. A status flag will appear if the engine is operating in cold mode. This may limit engine speed.Throttle Signal
Monitor the status for "Throttle Position" on Cat ET. Verify that the status for "Throttle Position" is stable and that the engine is able to reach high idle speed. Refer to the appropriate diagnostic functional test for your application:
Troubleshooting, "Throttle Position Sensor Circuit - Test"
Troubleshooting, "Throttle Switch Circuit - Test"
Troubleshooting, "Speed Control - Test"Intake Manifold (Boost) Pressure Sensor or Atmospheric Pressure Sensor
Monitor the status of "Fuel Position", "Rated Fuel Limit", and "FRC Fuel Limit" on Cat ET while the engine is operating under full load. These parameters should reflect the information below.
Table 1
"Fuel Position" = "Rated Fuel Limit"
and
"Fuel Position" < "FRC Fuel Limit" If "Fuel Position" equals "Rated Fuel Limit" and "Fuel Position" is less than "FRC Fuel Limit", the electronics are operating correctly. Otherwise, proceed with the next Step.
Monitor the status of "Intake Manifold (Boost) Pressure" and "Atmospheric Pressure" for normal operation on Cat ET. When the engine is not running, the correct "Intake Manifold (Boost) Pressure" is 0 kPa (0 psi).
Verify that the intake manifold (boost) pressure sensor is operating properly. 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.
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.
Prime the fuel 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 the Systems Operation/Testing and Adjusting.
Cold weather adversely affects the characteristics of the fuel. Refer to the Operation and Maintenance Manual.
Check the fuel pressure during engine cranking. Check the fuel pressure after the fuel filter. Refer to the Systems Operation/Testing and Adjusting. 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. Air Inlet and Exhaust System
Replace plugged air filters and/or clean the filters. Leaks in the air inlet manifold system can lower Inlet manifold pressure.
Check the exhaust system for restrictions and/or for leaks. Accessory Equipment
Check all accessory equipment for problems that may create excessive load on the engine. Repair any