Cummins ISB4.5 CM2150 Fault Code: 3561 PID: SPN: 3361 FMI: 5 Aftertreatment Diesel Exhaust Fluid Dosing Unit – Current Below Normal or Open Circuit.

Posted by PerDiezel Solutions on January 20, 2026

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

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

Conditions for Setting the Fault Codes
The aftreatment diesel exhaust fluid controller detects that the diesel exhaust dosing unit circuit is open.

Action Taken When the Fault Code is Active
-The electronic control module (ECM) illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (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, and 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
-Open circuit in the aftertreatment diesel exhaust fluid dosing unit
-Open circuit in the aftertreatment diesel exhaust fluid controller harness
-Malfunctioning aftertreatment diesel exhaust fluid controller.

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.

Cummins ISB4.5 CM2150 Fault Code: 3558 PID: SPN: 3361 FMI: 3 Aftertreatment Diesel Exhaust Fluid Dosing Unit – Voltage Above Normal or Shorted to High Source.

Cummins ISB4.5 CM2150 Fault Code: 3557 PID: SPN: 3360 FMI: 2 Aftertreatment Diesel Exhaust Fluid Controller – Data Erratic, Intermittent, or Incorrect.

Cummins ISB4.5 CM2150 Fault Code: 3555 PID: SPN: 1081 FMI: 9 Engine Wait to Start Lamp – Abnormal Update Rate.

Cummins ISB4.5 CM2150 Fault Code: 3548 PID: SPN: 5392 FMI: 31 Aftertreatment Diesel Exhaust Fluid Dosing Unit Loss of Prime – Condition Exists.

Cummins ISB4.5 CM2150 Fault Code: 3542 PID: SPN: 51 FMI: 2 Engine Intake Throttle Actuator Position Sensor – Data Erratic, Intermittent, or Incorrect.

WARNING!