P1451

P1451-DIESEL PARTICULATE FILTER SYSTEM PERFORMANCE



Theory of Operation

The Engine Control Module (ECM) monitors the soot load in the After treatment Diesel Particulate Filter. The soot load in the After treatment 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 After treatment 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 After treatment 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 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. 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 After treatment 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NOTE: The Mobile Desoot procedure has been replaced by a scan tool initiated Stationary Desoot procedure.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 After treatment Diesel Particulate Filter has been regenerated with an active desoot initiated during normal driving conditions. No further action is required. Erase the DTC and deliver vehicle to the customer.

2. ACTIVE OR STORED DTC
1. With the scan tool, read DTCs.

Is DTC Active or Stored?

Active

- Replace the After treatment Diesel Particulate Filter and reset the regenerative timers with the scan tool.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

Stored

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