Cummins ISB4.5 CM2150 Fault Code: 3574 PID: SPN: 4334 FMI: 18 Aftertreatment Diesel Exhaust Fluid Pressure Sensor – Data Valid but Below Normal Operating Range – Moderately Severe Level.

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 the diesel exhaust fluid dosing unit is in the priming or dosing state.

Conditions for Setting the Fault Codes
The diesel exhaust fluid controller detects that the dosing unit is unable to build or maintain adequate diesel exhaust fluid line 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
-This fault code can not be cleared with INSITE™ electronic service tool
-To validate the repair, use INSITE™ to perform the “Diesel Exhaust Fluid Doser Override Test” under the “ECM Diagnostics Test” menu..
-The ECM will turn off the amber CHECK ENGINE lamp and/or MIL immediately after the diagnostic runs and passes.
-Use INSITE™ electronic service tool to verify the fault code is inactive.
-The inactive fault code will be cleared from the memory after 9600 hours of engine operation without a reoccurrence.

Shop Talk
Troubleshoot other active SCR related faults before this fault.

Possible Causes
-Low diesel exhaust fluid tank level
-Blocked, restricted, or frozen diesel exhaust fluid dosing unit supply line
-Blocked or restricted diesel exhaust fluid tank filter
-Blocked or restricted diesel exhaust fluid dosing unit filter
-Blocked or restricted diesel exhaust fluid dosing unit supply line fitting
-Malfunctioning diesel exhaust fluid dosing unit
-Contaminated diesel exhaust fluid.