Circuit DescriptionThe variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device that receives information via the J1939 data link from the primary engine electronic control module (ECM). The VGT actuator performs its own diagnostics and reports errors back to the primary engine ECM using the J1939 data link.

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

Conditions for Running the DiagnosticsThis diagnostic runs 5 minutes after engine start up if coolant temperature is greater than 71?C [160?F].

Conditions for Setting the Fault CodesConditions for setting the fault code: The internal position reference is not detected during the ECM commanded span check due to mechanical system binding or internal condition. The actual VGT actuator position is not known.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE light and/or Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.VGT actuation will be disabled.Conditions for Clearing the Fault CodeTo validate the repair, perform a key cycle, and then start the engine and let it idle for 5 minutes.The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passesThe ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.For On-Board Diagnostic (OBD) engines, the ECM will turn off the 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 TalkThis fault code is logged when one of the following error conditions exists.

The gear alignment between the actuator and the turbocharger housing is misaligned.Foreign material in the VGT turbocharger can prevent the sliding nozzle from moving to the desired position.

Possible Cause:1) Turbocharger failure2) Turbocharger actuator failure3) ECM calibration