P1451
P1451-DIESEL PARTICULATE FILTER SYSTEM PERFORMANCE
For a complete wiring diagram Refer to Diagrams/Electrical.
Theory of Operation
The Engine Control Module (ECM) monitors the soot load in the Diesel Particulate Filter. The soot load in the Diesel Particulate Filter is estimated by the ECM using the Exhaust Differential Pressure Sensor values and the calculated soot output of the engine. Under normal operating conditions the 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 that it is necessary to modify the vehicles driving routine/duty-cycle (see Owner's Manual for details) in order to allow the Diesel Particulate Filter system to self clean. There is not a MIL lamp associated with this fault code, though the driver will be notified via the EVIC message.
- When Monitored:
Engine Running
- Set Condition:
The 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.
Initial Inspection and Diagnostic Overview
1. ACTIVE OR STORED DTC
NOTE: DTC P1451 is usually the result of a driveability or fuel system failure. This DTC indicates that there is an excessive soot level in the Aftertreatment Diesel Particulate Filter and the Diesel Particulate Filter needs to be regenerated. This can be caused by the customers driving habits, (not allowing the vehicle to actively regenerate the Diesel Particulate Filter on it's own), or due to a driveability concern causing excessive soot generation in the exhaust system. 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 this DTC to return prematurely.
1. Ignition on, engine not running.
2. With the scan tool, read DTCS.
Is the DTC Active or Stored?
Active
^ Perform a scan tool initiated Stationary Desoot.
NOTE: The Mobile Desoot procedure has been replaced by a scan tool initiated Stationary Desoot procedure. The scan tool initiated Stationary Desoot procedure can only be performed if the DTC is active and the ECM is at the latest software version.
^ Go To 2
Stored
^ The Aftertreatment Diesel Particulate Filter has been regenerated with an active desoot initiated during normal driving conditions.
^ Perform the DIESEL AFTERTREATMENT VALIDATION - 6.7L. Refer to Alldata library for information.
2. PERFORM THE AFTERTREATMENT INSPECTION
1. With the scan tool, read DTCs.
Is DTC Active or Stored?
Active
^ Perform the AFTERTREATMENT INSPECTION GUIDELINE procedure. Refer to Alldata library for information.
^ Perform the DIESEL AFTERTREATMENT VALIDATION - 6.7L. Refer to Alldata library for information.
Stored
^ Erase DTC. Repair complete.
^ Perform the DIESEL AFTERTREATMENT VALIDATION - 6.7L. Refer to Alldata library for information.
Diagnostic Test
1. OTHER DTCS
Ignition on, engine not running.
With the scan tool, read DTCs.
Are any other DTCs Active?
Yes
- Repair all other DTC's.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 2
2. BASE ENGINE FAILURE
Check for base engine failures.
Check for potential cause of excessive soot generation in the engine.
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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 3
3. CYLINDER MISFIRE
Start the engine.
Allow the engine to idle.
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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 4
4. EXHAUST TEMPERATURE SENSOR(S)
Turn the ignition off for 5 minutes.
Turn the ignition on.
With the scan tool check the temperature values of the Exhaust Temperature Sensors.
Are the Exhaust Temperature Sensors reading within 6 degrees C of each other?
Yes
- Go To 5
No
- Replace the Exhaust Temperature Sensor that is out of context.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
5. EXCESSIVE ENGINE OIL BEING INTRODUCED INTO THE AFTERTREATMENT SYSTEM FROM THE ENGINE
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 POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test
No
- Go To 6
6. REGENERATION OF AFTERTREATMENT PARTICULATE FILTER
Technician should drive vehicle per service information in response to level of EVIC Message Center Notification to facilitate Active Regeneration of the Aftertreatment Particulate Filter.
After the Active Regeneration of the Aftertreatment Particulate Filter, Clear DTC with Service Tool Is DTC P1451 still Active?
Yes
- Go To 7
No
- Repair completed, inform Owner of vehicle duty cycle requirements
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test
7. EXHAUST PRESSURE SENSOR
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 POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test
No
- Go To 8
8. DTC STORED
With the scan tool, read DTCs.
Is DTC Stored?
Yes
- Erase DTC. Repair complete
- Perform POWERTRAIN VERIFICATION TEST (DIESEL). Powertrain Verification Test
No
- Go To 1