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 runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault CodesThe turbocharger actuator calibration revision in the VGT actuator is not compatible with the ECM software.

Action Taken When the Fault Code is ActiveThe ECM illuminates the red STOP ENGINE lamp immediately after the diagnostic runs and fails.Conditions for Clearing the Fault CodeTo validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.The ECM will turn off the red STOP ENGINE lamp immediately after 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 TalkThe turbocharger actuator interface level in the VGT actuator is not compatible with the ECM software.

Possible Cause:1) ECM calibration