Cummins ISB4.5 CM2150 Fault Code: 3559 PID: SPN: 3361 FMI: 4 Aftertreatment Diesel Exhaust Fluid Dosing Unit – Voltage Below Normal or Shorted to Low Source.

Circuit Description
The diesel exhaust fluid dosing unit performs many functions, one of which is to generate adequate diesel exhaust fluid pressure in the lines using a pump to allow for dosing. The diesel exhaust fluid controller provides a battery voltage supply and a ground to the diesel exhaust fluid dosing unit. The controller also supplies a signal to the dosing unit to control the diesel exhaust fluid output. This signal changes based on the diesel exhaust fluid pressure being commanded.

Component Location
The aftertreatment diesel exhaust fluid dosing unit location is original equipment manufacturer (OEM) dependent. Refer to the OEM service manual for more infomation.

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

Conditions for Setting the Fault Codes
The aftertreatment diesel exhaust fluid controller detects that the aftertreatment diesel exhaust fluid dosing unit voltage is below a calibratible value.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE lamp and/or the MIL immediately when the diagnostic runs and fails.
-Diesel exhaust fluid injection into the aftertreatment system is disabled.
-Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code
-To validate the repair, perform a key cycle. Then start the engine and let it idle for 1 minute.
-The fault code status displayed by the 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 after the diagnostic runs and passes.
-For OBD engines, the ECM will turn off the MIL after 3 consecutive trips where the diagnostic runs and passes.
-The “Reset All Faults” command in the INSITE electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications

Possible Causes
-Short to ground in the diesel exhaust fluid dosing unit
-Short to ground in the diesel exhaust fluid controller harness
-Malfunctioning aftertreatment diesel exhaust fluid controller.