P242F

P242F-DIESEL PARTICULATE FILTER RESTRICTION - ASH ACCUMULATION



Theory of Operation

The engine after treatment system monitors the soot load in the after treatment Diesel Particulate Filter. Under normal operating conditions, the after treatment Diesel Particulate Filter is self-cleaning, where soot is converted to ash. Under light load operating conditions, the driver may be notified via the vehicle's EVIC message center that it may be necessary to modify the vehicles driving routine in order to allow the after treatment Diesel Particulate Filter system to self clean. If the vehicle's EVIC message center notification is ignored, the vehicle will eventually derate the engine and set a DTC and MIL lamp, requiring service. The soot load in the after treatment diesel particulate filter is estimated using the Exhaust Pressure Sensor and the calculated soot output of the engine. This fault code can be triggered if the application is not operating at a duty cycle high enough to actively regenerate the after treatment Diesel Particulate Filter. It may be necessary to increase the duty cycle of the application in order to prevent plugging of the after treatment Diesel Particulate Filter. This fault will be triggered if the Engine Control Module (ECM) detects that the soot load of the after treatment Diesel Particulate Filter has surpassed the most severe level threshold. The after treatment Diesel Particulate Filter needs to be replaced, do not regenerate this filter. The ECM will illuminate the MIL lamp immediately when the diagnostic runs and fails. The driver will be notified via the vehicle's EVIC Message Center. The ECM will also initiate a derate of engine power output in an effort to protect the vehicle after treatment system. The ECM will turn off the MIL lamp immediately after the soot load in the after treatment Diesel Particulate Filter has dropped below the severe level threshold (this should be accomplished through replacing the after treatment Diesel Particulate Filter) and the DTC has been cleared.

- When Monitored:
The diagnostic runs continuously when the engine is running.

- Set Condition:
The Engine Control Module (ECM) detects that the soot load of the after treatment Diesel Particulate Filter has surpassed the most severe level threshold. The After treatment Diesel Particulate Filter requires replacement and the EGR Valve needs to be cleaned.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
DTC ACTIVE OR STORED

NOTE: If there are any DTCs present for the Exhaust Temperature Sensors or Exhaust Pressure Sensor, diagnose those DTCs before proceeding with this test procedure.

1. Ignition on, engine not running.
2. With the scan tool, read DTCs.

Is the DTC Active or Stored?

Active

- Replace the after treatment Diesel Particulate Filter and reset the regenerative timers with the scan tool. Remove and clean the EGR Valve. Perform the CHECKING ENGINE MISFIRE / RUNS ROUGH / PERFORMANCE test procedure. Checking Engine Misfire / Runs Rough / Performance Test.
NOTE: DTC P242F is usually the result of a driveability or fuel system failure. This DTC indicates that the Diesel Particulate Filter is either face plugged or filled with ash. If there are any other DTCs or driveability concerns present with this DTC, diagnose and repair those concerns before continuing with this test procedure. Not repairing the cause of the excess soot being generated will cause the Diesel Particulate Filter to fill with soot too often and fail prematurely.

- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Repair completed. No further action is required, inform Owner of vehicle duty cycle requirements.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.