P242F

P242F-DIESEL PARTICULATE FILTER RESTRICTION - ASH ACCUMULATION

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The engine aftertreatment system monitors the soot load in the aftertreatment Diesel Particulate Filter. Under normal operating conditions, the aftertreatment 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 aftertreatment 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 aftertreatment 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 aftertreatment Diesel Particulate Filter. This fault code indicates that the exhaust temperatures exiting the turbocharger are not high enough to actively regenerate the soot that is trapped in the aftertreatment Diesel Particulate Filter. It may be necessary to increase the duty cycle of the application in order to prevent plugging of the aftertreatment Diesel Particulate Filter. This fault will be triggered if the Powertrain Control Module (PCM) detects that the soot load of the aftertreatment Diesel Particulate Filter has surpassed the most severe level threshold. The aftertreatment Diesel Particulate Filter needs to be replaced, do not regenerate this filter. The PCM will illuminate the MIL lamp immediately when the diagnostic runs and fails. The driver will be notified via the vehicle's EVIC Message Center (CATALYST FULL: SERVICE REQD). The Powertrain Control Module (PCM) will also initiate a derate of engine power output in an effort to protect the vehicle aftertreatment system. The PCM will turn off the MIL lamp immediately after the soot load in the aftertreatment Diesel Particulate Filter has dropped below the severe level threshold (this should be accomplished through replacing the aftertreatment Diesel Particulate Filter) and the DTC has been cleared.

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

- Set Condition:
The Powertrain Control Module (PCM) detects that the ash load of the aftertreatment Diesel Particulate Filter has surpassed the most severe level threshold. The aftertreatment Diesel Particulate Filter requires replacement.





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 aftertreatment 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.