Cummins ISC CM2150 (2007-09) 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.

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM.

The switch can be monitored for proper operation with 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 3-position switch has three states:

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

The 2-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 problem.