Cummins ISB CM850 (2003-06) Fault Code: 2558 PID: SID 57 SPN: 697 FMI: 4 Auxiliary PWM Driver #1 – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the analog torque circuit.

Cummins ISB CM850 (2003-06) Fault Code: 2558 PID: SID 57 SPN: 697 FMI: 4 Auxiliary PWM Driver #1 – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the analog torque circuit.

Possible causes:

1)A faulty transmission shift modulator
2)An short circuit to ground on the output device driver line
3)A short pin to pin in the output device driver line.

Possible repairs:

1)Replace the transmission shift modulator.
2)Repair or replace the OEM harness.
3)The removal and installation of the connector may correct the fault.
4)Replace the ECM.