Circuit DescriptionThe ECM calculates an aftertreatment diesel particulate filter flow resistance, using the aftertreatment diesel particulate filter differential pressure and calculated exhaust flow rate.

Component LocationThe aftertreatment diesel particulate filter is located in the exhaust system and is installed by the original equipment manufacturer (OEM). Refer to the OEM service manual.

Conditions for Running the DiagnosticsThis diagnostic only runs after successful completion of an active regeneration of the aftertreatment diesel particulate filter.

Conditions for Setting the Fault CodesThe ECM detects that the aftertreatment diesel particulate filter flow resistance is lower than a threshold for 2 minutes.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp and/or malfunction indicator lamp (MIL) after the diagnostic fails on two consecutive trips.The EGR valve will be closed.Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.Conditions for Clearing the Fault CodeA successful regeneration must be performed.To validate the repair, start the engine and let it idle for 1 minute.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 TalkPossible causes of this fault code include:

A damaged aftertreatment diesel particulate filter differential pressure sensorMissing or malfunctioning aftertreatment diesel particulate filter differential pressure sensor tubesMalfunction aftertreatment diesel particulate filter.Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and datalink 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) Aftertreatment DPF differential pressure sensor failure2) ECM calibration