Cummins ISB CM850 (2003-06) Fault Code: 528 PID: 93 SPN: 93 FMI: 2 Auxiliary Alternate Torque Validation Switch – Data Erratic, Intermittent, or Incorrect. An error has been detected in the alternate torque switch circuit.

Cummins ISB CM850 (2003-06) Fault Code: 528 PID: 93 SPN: 93 FMI: 2 Auxiliary Alternate Torque Validation Switch – Data Erratic, Intermittent, or Incorrect. An error has been detected in the alternate torque switch circuit.

The switch can be monitored for proper operation in INSITE? electronic service tool. If the switch is changing state correctly on the service tool, then the problem does not lie in the switch circuit.

The three position-switch has three states:

1)Position 1 – open
2)Position 2 – closed
3)Position 3 – 1500 ohm resistance

The two position-switch has two states:

1)Position 1 – open
2)Position 2 – closed

Possible repairs:

1)Replace the alternate torque switch.
2)Repair or replace the OEM harness.
3)The removal and reinstallation of the connector may correct the fault.