Cummins ISB4.5 CM2150 Fault Code: 1681 PID: SPN: 3361 FMI: 12 Aftertreatment Diesel Exhaust Fluid Dosing Unit – Bad Intelligent Device or Component.

Circuit Description
The aftertreatment diesel exhaust fluid dosing unit communicates to the primary engine electronic control module (ECM) through the J1939 data link network. The aftertreatment diesel exhaust fluid dosing unit precisely measures the amount of aftertreatment diesel exhaust fluid to be injected into the aftertreatment system. The aftertreatment diesel exhaust fluid dosing unit has three primary cycles. A priming cycle at initial key on makes sure that aftertreatment diesel exhaust fluid is available at the aftertreatment diesel exhaust fluid dosing unit. During the dosing cycle, aftertreatment diesel exhaust fluid is being delivered to the aftertreatment dosing valve. A purge cycle occurs when the engine is turned off. The purge cycle makes sure that all the aftertreatment diesel exhaust fluid is removed from the aftertreatment line and dosing valve.

Component Location
The aftertreatment diesel exhaust fluid dosing unit location is 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 aftertreatment diesel exhaust fluid dosing unit detects an internal error.

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.
-Diesel exhaust fluid injection into the aftertreatment system is disabled.
-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, start the engine and let it idle for 1 minute.
-The ECM will turn off the amber CHECK ENGINE lamp and/or MIL immediately after the diagnostic runs and passes.
-Use INSITE™ electronic service tool to verify 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 1681 is triggered when the aftertreatment diesel exhaust fluid dosing unit has detected an internal error.