Cummins ISB4.5 CM2150 Fault Code: 3679 PID: SPN: 3361 FMI: 11 Aftertreatment Diesel Exhaust Fluid Dosing Unit – Root Cause Not Known.

Posted by PerDiezel Solutions on January 20, 2026

Circuit Description
The diesel exhaust fluid dosing unit monitors its internal temperature and reports it back to the diesel exhaust fluid controller at initial key-ON via the aftertreatment diesel exhaust fluid dosing unit signal/dosing unit temperature wire. After the temperature message has been sent from the dosing unit to the controller, this shared wire is switched over to be used for dosing unit pump control.

Component Location
The aftertreatment diesel exhaust fluid dosing unit location is OEM dependent. Refer to the OEM troubleshooting manual for more information.

Conditions for Running the Diagnostics
This diagnostic runs at initial key-ON.

Conditions for Setting the Fault Codes
The diesel exhaust fluid dosing unit and the diesel exhaust fluid controller are not able to acknowledge each other at key-ON, and can not initialize.

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 cannot be cleared with INSITE™ electronic service tool.
-Upon completion of the repair, a key cycle is required in order to get the diagnostic to run again and make the fault go inactive.
-The ECM will turn off the amber CHECK ENGINE lamp and/or MIL immediately after the diagnostic runs and passes.
-The inactive fault code will be cleared from the memory after 9600 hours of engine operation without a reoccurrence.

Possible Causes
-Short or open circuit in the aftertreatment wiring harness
-Malfunctioning diesel exhaust fluid dosing unit.

Cummins ISB4.5 CM2150 Fault Code: 3651 PID: SID 254 SPN: 3031 FMI: 18 Aftertreatment Diesel Exhaust Fluid Tank Temperature – Data Valid But Below Normal Operating Range – Moderately Severe Level.

Cummins ISB4.5 CM2150 Fault Code: 3648 PID: SID 254 SPN: 5480 FMI: 16 Aftertreatment Diesel Exhaust Fluid Controller Temperature – Data Valid But Above Normal Operating Range – Moderately Severe Level.

Cummins ISB4.5 CM2150 Fault Code: 3616 PID: SPN: 2633 FMI: 7 Engine VGT Nozzle Position – Mechanical System Not Responding or Out of Adjustment.

Cummins ISB4.5 CM2150 Fault Code: 3612 PID: SPN: 3361 FMI: 7 Aftertreatment Diesel Exhaust Fluid Dosing Unit – Mechanical System Not Responding or Out of Adjustment.

Cummins ISB4.5 CM2150 Fault Code: 3598 PID: SPN: 3360 FMI: 19 Aftertreatment Diesel Exhaust Fluid Controller – Received Network Data In Error.

Cummins ISB4.5 CM2150 Fault Code: 3597 PID: SID 254 SPN: 3360 FMI: 9 Aftertreatment Diesel Exhaust Fluid Controller – Abnormal Update Rate.

WARNING!