Cummins ISX11.9 CM2250 (2010-12) Fault Code: 3649 PID: SPN: 5024 FMI: 10 Aftertreatment Intake Nox Sensor Heater- Abnormal Rate of Change

Circuit Description
The aftertreatment intake NOx sensor is a smart device that communicates with the engine control module (ECM) via the J1939 data link. The aftertreatment intake NOx sensor performs internal diagnostics and reports malfunctions back to the primary ECM, using the J1939 data link. The NOx sensor is permanently attached to the NOx control module. They are serviced as a single component and can not be replaced individually. The aftertreatment intake NOx sensor is used to measure the NOx emissions at the intake of the aftertreatment system.

Component Location
The aftertreatment intake NOx sensor is mounted on the engine near the turbocharger turbine outlet.

Conditions for Running the Diagnostics
This diagnostic runs when the diesel oxidation catalyst (DOC) intake temperature at the aftertreatment intake NOx sensor is above 200?C [392?F] and the engine is operating.
Conditions for Setting the Fault Codes
The ECM detects that the NOx sensor heater is unable to maintain its normal operating temperature.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE light and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
The engine speed operating range is limited to the adjustable parameter ?Maximum Engine Speed without VSS?.
Cruise Control, Gear-Down Protection, and Road Speed Governor features will be disabled.
Conditions for Clearing the Fault Code
To validate the repair, start and operate the engine to raise exhaust temperatures. This can be done by either driving the vehicle or initiating a stationary regeneration using INSITE? electronic service tool.
The DOC intake temperature at the aftertreatment intake NOx sensor must be above 200?C [392? F] before the sensor can perform its internal diagnostics.
The fault code status displayed by 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 On-Board Diagnostics (OBD) engines, the ECM will turn off the MIL after three consecutive trips where the diagnostic runs and passes.
The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk
The NOx sensor heater is internal to the NOx sensor assembly and can not be serviced separately.

Possible causes of this fault code include:

Damaged aftertreatment intake NOx sensor
Intermittent power connection to the aftertreatment intake NOx sensor.
Reference the appropriate original equipment manufacturer (OEM) wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and data link communication issues with aftertreatment components, it is highly recommended that the OEM power distribution center fuses and relays be thoroughly checked for loose, missing, or intermittent connections.

Possible Cause:
1) Loose Connections/ Terminals
2) OEM harness
3) ECM calibration