Circuit DescriptionThe variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device and receives information via the J1939 data link from the primary engine control module (ECM). The VGT actuator performs its own diagnostics and reports malfunctions back to the primary engine ECM, using the J1939 data link. The ECM then decodes the error message and converts it to a fault code.

Component LocationThe VGT actuator is located on the turbocharger bearing housing.

Conditions for Running the DiagnosticsThis diagnostic has to meet specific engine and aftertreatment conditions to run and complete.

Conditions for Setting the Fault CodesThe Variable Geometry Turbocharger (VGT) actuator position could not meet the commanded position for greater than 10 seconds.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp and/or Malfunction Indicator Lamp (MIL) after the diagnostic fails on two consecutive trips.

The VGT actuator will continue to attempt to meet commanded position, even when the CHECK ENGINE lamp is on.Active and stationary regeneration of the diesel particulate filter will be disabled.Exhaust Gas Recirculation (EGR) valve operation will be disabled.Diesel exhaust fluid injection into the aftertreatment system is disabled.Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.Conditions for Clearing the Fault CodeTo validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop and go city type driving and steady state highway type driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.To validate the repair using a Chassis Dynamometer, utilize a routine that incorporates acceleration and motoring events, steady state highway type operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop TalkPossible causes of this fault code include:

A malfunctioning turbochargerA malfunctioning turbocharger actuatorThe aftertreatment system must be inspected for potential damage after making the appropriate repair outlined in this fault code troubleshooting tree. Progressive damage to the aftertreatment system can possibly have occurred.

Possible Cause:1) Turbocharger assembly failure2) ECM calibration