Cummins ISB CM850 (2003-06) Fault Code: 222 PID: 108 SPN: 108 FMI: 4 Barometric Pressure Sensor Circuit – Voltage Below Normal, or Shorted to Low Source. Low signal voltage detected at barometric pressure circuit.

Posted by PerDiezel Solutions on January 18, 2026

The barometric 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 Fault Code 222, check for multiple faults.

Possible causes:

1)Signal circuit open or shorted to ground in the engine harness or sensor
2)Supply line open or shorted to ground.

On-Board Diagnostics (OBD) Information (Euro 4 Certified Engines):

1)The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2)The ECM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. The MIL lamp and fault code can also be cleared using the INSITE? service tool.
3)The fault code will be cleared from memory after 40 consecutive drive cycles where the diagnostic runs and passes.

On-Board Diagnostics (OBD) Information (Euro 4 Stage 1+ Certified Engines):

1)The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2)An engine torque derate will be activated after 50 hours of engine operation with the fault code active.
3)The ECM turns OFF the malfunction indicator lamp (MIL) after 1 ignition cycle that the diagnostic runs and does not fail. The MIL lamp cannot be cleared using the INSITE? service tool.
4)The fault code will be cleared from memory after 400 days or 9600 hours of engine operation.

Possible repairs:

1)Replace the barometric pressure sensor.
2)Replace the ECM.
3)Repair or replace the engine harness.

Cummins ISB CM850 (2003-06) Fault Code: 221 PID: 108 SPN: 108 FMI: 3 Barometric Pressure Sensor Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at barometric pressure circuit.

Cummins ISB CM850 (2003-06) Fault Code: 197 PID: 111 SPN: 111 FMI: 1 Coolant Level – Data Valid but Below Normal Operational Range – Moderately Severe Level. Low engine coolant level detected.

Cummins ISB CM850 (2003-06) Fault Code: 196 (3 wires) PID: 111 SPN: 111 FMI: 4 Coolant Level Sensor 1 Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at engine coolant level circuit.

Cummins ISB CM850 (2003-06) Fault Code: 196 (2 wires) PID: 111 SPN: 111 FMI: 4 Coolant Level Sensor 1 Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the engine coolant level circuit.

Cummins ISB CM850 (2003-06) Fault Code: 195 (3 wires) PID: 111 SPN: 111 FMI: 3 Coolant Level Sensor 1 Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at engine coolant level circuit.

Cummins ISB CM850 (2003-06) Fault Code: 195 (2 wires) PID: 111 SPN: 111 FMI: 3 Coolant Level Sensor 1 Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at engine coolant level circuit.

WARNING!