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

Component LocationThe aftertreatment diesel particulate filter differential 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.

Conditions for Running the DiagnosticsThis diagnostic consists of two parts.

One part runs when the keyswitch is initially turned ON before the engine is startedThe other part runs continuously when the engine is operating.Conditions for Setting the Fault CodesThe ECM detects that the aftertreatment diesel particulate filter differential pressure is greater than 1.5 kpa [0.44 in HG] 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 the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails for two consecutive trips.A default value of the aftertreatment diesel particulate filter differential pressure is used.Diesel exhaust fluid injection into the aftertreatment system is disabled.Active and stationary regeneration of the diesel particulate filter will be disabled.The exhaust gas recirculation (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 passes.For On-Board Diagnostic (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 differential pressure sensor readingHigh resistance in the aftertreatment diesel particulate filter differential pressure sensor SIGNAL or RETURN wiresDisconnected or damaged aftertreatment diesel particulate filter differential pressure sensor tubesPlugged aftertreatment differential pressure sensor ports could cause this fault code if pressure is held in the port after the engine is turned off.Reference the appropriate original equipment manufacturer (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) OEM harness3) ECM calibration