Cummins X15 CM2450 X124B (2018 & Newer) Fault Code: 1844 PID: PID 101 SPN: 101 FMI: 4 Crankcase Pressure Circuit- Voltage Below Normal or Shorted to Low Source

Circuit Description
The crankcase pressure sensor is used to monitor the pressure inside the crankcase. The engine control module (ECM) supplies the crankcase pressure sensor a 5 volt reference voltage. When the crankcase pressure is low, the sensor signal voltage is low. When the crankcase pressure is high, the sensor signal voltage is near the 5 volt reference voltage. The ECM monitors the crankcase pressure signal circuit voltage to calculate the pressure of the air within the crankcase.

Component Location
The crankcase pressure sensor is located near the crankcase ventilation filter.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected the crankcase pressure signal voltage was out of range low.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
A default value for the crankcase pressure reading is used.
Conditions for Clearing the Fault Code
To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk
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 of this fault code include:

Signal circuit open or shorted to ground in the engine harness or sensor
Supply wire open or shorted to ground.

Possible Cause:
1) ECM failure
2) Engine harness