Cummins X15 CM2450 X124B (2018 & Newer) Fault Code: 6646 PID: SPN: 5569 FMI: 2 Aftertreatment 1 Diesel Particulate Filter 1 Soot Sensor ECU Internal Temperature- Data Erratic, Intermittent, or Incorrect

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

Component Location
The aftertreatment particulate matter sensor location can vary depending on engine application. It is usually located in the exhaust system at the outlet of the selective catalytic reduction (SCR) catalyst.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes
The aftertreatment particulate matter sensor has detected a mismatch between the internal ECU temperature probes.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp and/or Malfunction Indicator Lamp (MIL) after the diagnostic fails on two consecutive trips.

Conditions for Clearing the Fault Code
To validate the repair, start the engine and let it idle 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.
For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (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
Possible causes for this fault include:

Malfunctioning aftertreatment particulate matter sensor

Possible Cause:
1) ECM calibration