Cummins ISB4.5 CM2150 Fault Code: 2976 PID: SPN: 3361 FMI: 2 Aftertreatment Diesel Exhaust Fluid Dosing Unit Temperature – Data Erratic, Intermittent, or Incorrect.

Circuit Description
For an air assisted SCR system, the aftertreatment diesel exhaust fluid dosing unit communicates important system operating information (including dosing unit internal temperature) to the primary engine electronic control module (ECM) via the J1939 data link network.

For an airless SCR system, the dosing unit reports its internal temperature to the diesel exhaust fluid controller via the dosing unit signal wire, and the diesel exhaust fluid controller communicates this information to the primary engine electronic control module (ECM ) via the J1939 data link network.

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

Conditions for Running the Diagnostics
The engine and keyswitch must be turned off for a period of 8 hours before this diagnostic will run. After an 8 hour cold soak, start and operate the engine at idle for 1 minute to run this diagnostic.

Conditions for Setting the Fault Codes
The ECM detects that the temperature reported by the aftertreatment diesel exhaust fluid dosing unit internal temperature sensor does not agree with other temperature sensors on the engine for two consecutive ignition cycles in which the diagnostic runs.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE lamp and/or the MIL immediately after the diagnostic runs and fails.
-Engine torque will be reduced.

Conditions for Clearing the Fault Code
-This fault code can not be cleared with INSITE™ electronic service tool.
-To validate the repair, the engine must be shut down with the keyswitch in the OFF position for a period of 8 hours. After the 8 hour cold soak, start the engine and let it idle for 1 minute to run the diagnostic.
-The ECM will turn off the amber CHECK ENGINE light and/or MIL immediately after the diagnostic runs and passes.
-Use INSITE™ electronic service tool to verify that 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
Fault code 2976 is triggered when the aftertreatment diesel exhaust fluid dosing unit internal temperature sensor is reading a different value than the other temperature sensors on the engine. This indicates a problem with the internal temperature sensor of the diesel exhaust fluid dosing unit. The 8 hour cold soak is required for the diagnostic to run so that the different temperature sensors can equalize at ambient temperature.