DUCT AS-AIR 5198340 - Caterpillar

Probable Causes
Diagnostic codes
ECM software
Air intake system or exhaust system
Valve lash
Turbocharger
Low compression (cylinder pressure)
Individual malfunctioning cylinder
Electronic unit injectorsRecommended Actions
Diagnostic Codes
Use the electronic service tool to check for active diagnostic codes. Troubleshoot any active codes before continuing with this procedure.ECM Software
Connect the electronic service tool to the diagnostic connector and check for the following conditions:
Check for the correct engine serial number
Check for the correct arrangement number
Check for the correct software
Use the electronic service tool to verify any active diagnostic codes.
If diagnostic codes are present, the Electronic Control Module (ECM) must be programmed with the correct information.
If the repairs have not eliminated the fault proceed to "Air Intake System or Exhaust System". Air Intake System or Exhaust System
Check the air filter restriction indicator, if equipped.
Ensure that the air filter is clean and serviceable.
Check the air intake and the exhaust system for the following defects:
Blockages
Restrictions
Damage to the air intake and exhaust lines and hoses
Make all necessary repairs to the engine.
If the fault has not been eliminated, proceed to "Valve Lash". Valve Lash
Ensure that the valve lash is correct. Reset the valve lash if it is not correct. Refer to Systems Operation, Testing and Adjusting, "Engine Valve Lash - Inspect/Adjust".If the repair does not eliminate the fault proceed to "Turbocharger".Turbocharger
Note: The turbocharger that is installed on this engine is a nonserviceable item. If any mechanical fault exists, then the turbocharger must be replaced.
Ensure that the mounting bolts for the turbocharger are tight.
Check that the oil drain for the turbocharger is not blocked or restricted.
Check that the compressor housing for the turbocharger is free of dirt, debris and damage.
Check that the turbine housing for the turbocharger is free of dirt, debris and damage.
Check that the turbine blades rotate freely in the turbocharger.
Ensure that the wastegate on the turbocharger is adjusted correctly. Refer to Systems Operation, Testing and Adjusting, "Wastegate - Inspect". If the wastegate actuator is faulty, replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install".
If necessary, replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install".
Check that the repairs have eliminated the faults.
If the repairs have not eliminated the fault proceed to "Low Compression (Cylinder Pressure)". Low Compression (Cylinder Pressure)
Perform a compression test. Refer to Systems Operation, Testing and Adjusting, "Compression - Test ".
If low compression is noted on any cylinders, investigate the cause and rectify the cause. Possible causes of low compression are shown in the following list:
Loose glow plugs
Faulty piston
Faulty piston rings
Worn cylinder bores
Worn valves
Faulty cylinder head gasket
Damaged cylinder head
Perform all necessary repairs.
Ensure that the repairs have eliminated the faults.
If the repair does not eliminate the fault refer to "Individual Malfunctioning Cylinder". Individual Malfunctioning Cylinder
With the engine speed at a fast idle, use the electronic service tool to isolate one cylinder at a time. Note if there is any reduction in engine speed. If a reduction in engine speed is not noted, the isolated cylinder is not operating under normal conditions. If the isolation