Cummins ISB6.7 CM2350 (2013-17) Fault Code: 4956 PID: SPN: 520750 FMI: 13 Engine Variable Geometry Turbo (VGT) Software – Out of Calibration. VGT software does not match application.

Cummins ISB6.7 CM2350 (2013-17) Fault Code: 4956 PID: SPN: 520750 FMI: 13 Engine Variable Geometry Turbo (VGT) Software – Out of Calibration. VGT software does not match application.

Circuit Description
The 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 Location
The VGT actuator is located on the turbocharger bearing housing.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position.

Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected an application software mismatch with the Turbocharger actuator calibration.

Action Taken When the Fault Code is Active
The ECM illuminates the red STOP ENGINE lamp immediately after the diagnostic runs and fails.

Conditions for Clearing the Fault Code
1)To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2)The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3)The ECM will turn off the red STOP ENGINE lamp immediately after the diagnostic runs and passes.
4)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.

Possible Causes:
The turbocharger application identification number in the VGT actuator does not match the turbocharger application identification number in the ECM.