Cummins ISB CM850 (2003-06) Fault Code: 958 PID: 27 SPN: 2795 FMI: 2 VGT Position Sensor – Data erratic, intermittent, or incorrect. Intermittent variable geometry turbocharger (VGT) position information is being received by the electronic control module (ECM).

This fault code is caused by an internal failure of the variable geometry turbocharger (VGT) position sensor. This failure causes erratic readings of the variable geometry turbocharger (VGT) position. The troubleshooting information for fault code 958 is the same as fault code 1229. Refer to fault code 1229 for the fault code troubleshooting information.

Possible repairs:

1)Replace the turbocharger position sensor.
2)Replace the ECM.