Cummins ISB6.7 CM2150 (2007-09) Fault Code: 1843 PID: 101 SPN: 101 FMI: 3 Crankcase Pressure Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at the crankcase pressure 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 crankcase pressure sensor shares supply and return wires in the engine harness with other sensors. Opens and shorts in the engine harness can cause multiple fault codes to be active. Before troubleshooting, check for multiple fault codes.

Possible causes:

1)Open return circuit in the engine harness, connectors, or sensor
2)Signal wire shorted to sensor supply or battery voltage.

Possible repairs:

1)Replace the crankcase pressure sensor.
2)The removal and installation of the connector may correct the problem.
3)Repair or replace the engine harness.
4)Replace the ECM.