Circuit DescriptionThe engine control module (ECM) provides a 5 volt supply to the aftertreatment diesel particulate filter outlet pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The aftertreatment diesel particulate filter outlet pressure sensor provides a signal to the ECM on the aftertreatment diesel particulate filter outlet pressure sensor signal circuit. This sensor signal voltage changes based on the pressure at the outlet of the aftertreatment diesel particulate filter.

Component LocationThe aftertreatment diesel particulate filter outlet pressure sensor is mounted on the diesel particulate filter. It is a combination sensor that detects both diesel particulate filter differential pressure and outlet pressure. Refer to the original equipment manufacturer (OEM) service manual for exact location of the aftertreatment system

Conditions for Running the DiagnosticsThis diagnostic consists of two parts.

One part runs when the keyswitch is initially turned ON before the engine is started.The other part runs continuously when the engine is operating.Conditions for Setting the Fault CodesThe ECM detects that the aftertreatment diesel particulate filter outlet pressure is greater than 1.5 kpa [0.22 psi] or less than -1.5 kpa [0.22 psi] at initial key ON, or is not changing with engine conditions

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp and/or malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails for two consecutive trips.Active and stationary regeneration of the diesel particulate filter will be disabled.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 CodeTo validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop-and-go city driving and steady state highway driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.To validate the repair using a Chassis Dynamometer Test, utilize a routine that incorporates acceleration and motoring events, steady state highway operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.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 passesFor 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:

Stuck in-range aftertreatment diesel particulate filter outlet pressure sensor readingHigh resistance in the aftertreatment diesel particulate filter outlet pressure sensor SIGNAL or RETURN wiresHigher than expected diesel particulate filter outlet pressureExcessive diesel exhaust fluid deposits in the aftertreatment decomposition tubePlugged aftertreatment outlet pressure sensor ports could cause this fault code if pressure is held in the port after the engine is turned OFF.NOTE: It is possible to set this fault in a shop environment by performing a key cycle with the tailpipe connected to an exhaust ventilation system.

Reference the appropriate 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) Aftertreatment DPF differential pressure sensor failure2) OEM harness3) ECM failure