Cummins ISX CM870 (2003-06) Fault Code: 2384 PID: S027 SPN: 641 FMI: 4 Variable geometry turbocharger actuator driver circuit – voltage below normal or shorted to low source. Low voltage detected at turbocharger control valve circuit.

Turbocharger control valve command can be monitored with INSITE? electronic service tool. This parameter represents the ECM command to the turbocharger control valve, which in turn controls the variable geometry actuator position.

Possible causes:

1)Signal short circuit to ground
2)Short circuit to ground in the turbocharger control valve.

Possible repairs:

1)Replace the turbocharger control valve.
2)Replace the ECM.
3)Repair or replace the engine harness.