Cummins X15 CM2450 X124B (2018 & Newer) Fault Code: 6688 PID: SPN: 5835 FMI: 9 Aftertreatment 1 Particulate Sensor- Abnormal Update Rate

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 Engine Control Module (ECM) lost communication with the aftertreatment particulate matter sensor via the J1939 data link.

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:

Sensor supply wire open or shorted to ground
Sensor return wire open.

An open or short circuit in the SAE J1939 datalink circuit
Malfunctioning aftertreatment particulate matter sensor
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) ECM calibration