P1451

P1451-DIESEL PARTICULATE FILTER SYSTEM PERFORMANCE

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

Theory of Operation

The Engine Control Module (ECM) monitors the soot load in the Aftertreatment Diesel Particulate Filter. The soot load in the Aftertreatment Diesel Particulate Filter is estimated by the ECM using the Exhaust Pressure Sensor values and the calculated soot output of the engine. Under normal operating conditions the Aftertreatment Diesel Particulate Filter is self-cleaning, where accumulated soot is converted to ash. Under light load operating conditions, the driver may be notified via the vehicle's EVIC message center ("CATALYST FULL: SEE OWNERS MAN" message will be displayed) that it is necessary to modify the vehicles driving routine/duty-cycle 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 fault, requiring service. This fault code is an indication that the exhaust temperatures exiting the turbocharger are not high enough to allow active regeneration of the soot that is trapped in the Aftertreatment Diesel Particulate Filter. There is not a MIL lamp associated with this fault code, though the driver will be notified via the EVIC message and active regeneration will be disabled.

- When Monitored:
Engine running.

- Set Condition:
The Engine Control Module (ECM) will set this fault if it detects that the soot level has exceeded the normal desoot trigger threshold by a sufficient amount to indicate that the driver intervention is required.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

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

Are any other DTCs Active?

Yes

- Repair all other DTCs.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 2

2. BASE ENGINE FAILURE
1. Check for base engine failures.
2. Check for potential cause of excessive soot generation in the engine.
3. Potential causes include a stuck open Exhaust Gas Recirculation Valve or a Variable Geometry Turbocharger Actuator that is not moving correctly, faulty fueling or oil intrusion into the Aftertreatment/exhaust system.

Was a base engine failure found?

Yes

- Replace the failed base engine component causing the high black smoke levels. Replace the Exhaust Diesel Particulate Filter.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. CYLINDER MISFIRE
1. Start the engine.
2. Allow the engine to idle.
3. With the scan tool, read the Misfire counter status.

Is an engine misfire detected?

Yes

- Determine the cause of the engine misfire. Use scan tool Cylinder Cutout Test to isolate a failed injector. Replace the failed injector if necessary. Inspect the Aftertreatment system for possible damage.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. EXHAUST TEMPERATURE SENSORS
1. Turn the ignition off for 5 minutes.
2. Turn the ignition on.
3. With the scan tool check the temperature values of the Exhaust Temperature Sensors.

Are the Exhaust Temperature Sensors reading within 6°C (43°F) of each other?

Yes

- Go To 5

No

- Replace the Exhaust Temperature Sensor that is out of range.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. EXCESSIVE ENGINE OIL BEING INTRODUCED INTO THE AFTERTREATMENT SYSTEM FROM THE ENGINE
1. Remove the turbocharger outlet and inspect for signs of oil, fuel or moisture being introduced into the Aftertreatment system from the engine.

Was engine oil, fuel or moisture found in the turbocharger exhaust outlet?

Yes

- Locate the cause of possible diesel fuel or engine oil being carried from the engine into the Exhaust system. Inspect the Exhaust for possible damage.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 6

6. REGENERATION OF AFTERTREATMENT PARTICULATE FILTER
1. Technician should drive vehicle in response to level of EVIC Message Center Notification to facilitate active regeneration of the Aftertreatment Diesel Particulate Filter.
2. After the active regeneration of the Aftertreatment Diesel Particulate Filter, clear DTC with scan tool.
3. Turn the ignition off, wait 30 seconds.
4. Start the engine and let idle.
5. With the scan tool, read DTCs.

Is DTC P1451 still Active?

Yes

- Go To 7

No

- Repair completed, inform Owner of vehicle duty cycle requirements
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

7. EXHAUST PRESSURE SENSOR
1. Inspect the Exhaust Pressure Sensors and lines for signs or wear, damage or blockage.

Are the Exhaust Pressure Sensors or their lines worn, damaged or blocked?

Yes

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

No

- Go To 8

8. DTC STORED
1. With the scan tool, read DTCs.

Is DTC Stored?

Yes

- Erase DTC. Repair complete.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 1