Cummins ISB4.5 CM2150 Fault Code: 3596 PID: SPN: 4334 FMI: 2 Aftertreatment Diesel Exhaust Fluid Pressure Sensor – Data Erratic, Intermittent, or Incorrect.

Posted by PerDiezel Solutions on January 20, 2026

Circuit Description
The diesel exhaust fluid controller provides a 5 volt supply and a ground to the diesel exhaust fluid pressure sensor. The pressure sensor provides a signal to the diesel exhaust fluid controller on the sensor signal circuit. This sensor signal voltage changes based on the diesel exhaust fluid pressure supplied by the dosing unit. The diesel exhaust fluid controller will detect a low signal voltage at low diesel exhaust fluid pressures, and a high signal voltage at high diesel exhaust fluid pressures. The aftertreatment diesel exhaust fluid pressure sensor reading is communicated to the ECM via the engine data link.

Component Location
The aftertreatment diesel exhaust fluid pressure sensor is internal to the aftertreatment diesel exhaust fluid dosing unit and can not be serviced separately.

Conditions for Running the Diagnostics
This diagnostic runs when diesel exhaust fluid dosing unit is fully primed, and is actively maintaining diesel exhaust fluid pressure in the dosing system.

Conditions for Setting the Fault Codes
The diesel exhaust fluid dosing unit is unable to maintain the commanded diesel exhaust fluid pressure.

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.

Conditions for Clearing the Fault Code
-To validate the repair, the diesel exhaust fluid dosing system must be fully primed. This can be done by performing the Aftertreatment Diesel Exhaust Fluid Doser Pump Override test in INSITE™ electronic service tool.
-To validate the repair, start the engine and make sure the SCR dosing system is fully primed.
-The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
-The ECM will turn off the MIL after 3 consecutive ignition cycles that the diagnostic runs and passes.
-This fault code and MIL can also be cleared with INSITE™ electronic service tool.

Possible Causes
-Leaking diesel exhaust fluid lines
-Malfunctioning diesel exhaust fluid dosing unit

Cummins ISB4.5 CM2150 Fault Code: 3579 PID: SPN: 4376 FMI: 5 Aftertreatment Diesel Exhaust Fluid Return Valve – Current Below Normal or Open Circuit.

Cummins ISB4.5 CM2150 Fault Code: 3578 PID: SPN: 4376 FMI: 4 Aftertreatment Diesel Exhaust Fluid Return Valve – Voltage Below Normal or Shorted to Low Source.

Cummins ISB4.5 CM2150 Fault Code: 3577 PID: SPN: 4376 FMI: 3 Aftertreatment Diesel Exhaust Fluid Return Valve – Voltage Above Normal or Shorted to High Source.

Cummins ISB4.5 CM2150 Fault Code: 3576 PID: SPN: 3576 FMI: 5 Aftertreatment Diesel Exhaust Fluid Tank Heater – Current Below Normal or Open Circuit.

Cummins ISB4.5 CM2150 Fault Code: 3575 (Airless) PID: SPN: 4334 FMI: 16 Aftertreatment Diesel Exhaust Fluid Pressure Sensor – Data Valid But Above Normal Operating Range – Moderately Severe Level.

Cummins ISB4.5 CM2150 Fault Code: 3575 PID: SPN: 4334 FMI: 16 Aftertreatment Diesel Exhaust Fluid Pressure Sensor – Data Valid but Above Normal Operating Range – Moderately Severe Level.

WARNING!