Cummins ISB4.5 CM2150 Fault Code: 4139 PID: SPN: 1746 FMI: 2 Security Device – Data Erratic, Intermittent, or Incorrect.

Posted by PerDiezel Solutions on January 20, 2026

Circuit Description
The OEM security device is an optional device connected to the primary engine control module (ECM) through a J1939 data link network. Messages sent from the security device are received by the Cummins® ECM and are used to control the anti-theft features. The Cummins® ECM and security device must be configured properly so that proper operation of the system will occur.

Component Location
The J1939 data link wiring and location of OEM installed J1939 devices varies by OEM. See equipment manufacturer service information for component location

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

Conditions for Setting the Fault Codes
This fault code is active when the OEM security device has not been deactivated.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.
-The engine may not start.

Conditions for Clearing the Fault Code
-To validate the repair, perform a key cycle, and leave the key in the ON position for 1 minute.

The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.

-The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes

Shop Talk
This fault code is active when the anti-theft device has not been deactivated. The engine will not start until proper authorization has been activated.

Cummins ISB4.5 CM2150 Fault Code: 4138 PID: SPN: 1746 FMI: 9 Security Device – Abnormal Update Rate.

Cummins ISB4.5 CM2150 Fault Code: 3879 PID: SPN: 3364 FMI: 0 Aftertreatment Diesel Exhaust Fluid Quality – Data Valid But Above Normal Operating Range – Most Severe Level.

Cummins ISB4.5 CM2150 Fault Code: 3878 PID: SPN: 3364 FMI: 2 Aftertreatment Diesel Exhaust Fluid Quality – Data Erratic, Intermittent, or Incorrect.

Cummins ISB4.5 CM2150 Fault Code: 3877 PID: SPN: 3364 FMI: 12 Aftertreatment Diesel Exhaust Fluid Quality – Bad Intelligent Device or Component.

Cummins ISB4.5 CM2150 Fault Code: 3876 PID: SPN: 3364 FMI: 7 Aftertreatment Diesel Exhaust Fluid Quality – Mechanical System Not Responding or Out of Adjustment.

Cummins ISB4.5 CM2150 Fault Code: 3868 PID: SPN: 3364 FMI: 9 Aftertreatment Diesel Exhaust Fluid Quality – Abnormal Update Rate.

WARNING!