Cummins Fault Code 6688

FAULT CODE 6688
Aftertreatment 1 Particulate Sensor - Abnormal Update Rate

Overview

CODE
REASON
EFFECT

Fault Code: 6688
PID:
SPN: 5835
FMI: 9/9
LAMP: Amber
SRT:

No communication or an invalid data transfer rate detected on the J1939 data link between the ECM and the aftertreatment particulate matter sensor.

Possible reduced engine performance.

Cummins Fault Code 6688
SAE J1939 Datalink

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 the recommended Cummins electronic service tool or equivalent 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 the recommended Cummins electronic service tool or equivalent can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk

Possible causes of this fault code include:

  • 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.

XTuning.VN

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