NOTE: If any other codes active, fix those first

PROBABLE CAUSES:
1. DOC outlet temperature sensor harness/connector.
2. DOC outlet temperature sensor.
3. Failed fuel injector.
4. Remove the DPF and inspect for coolant or oil contamination. If found, find source of leak.
5. Perform a parked regen.
6. Electrical connections upstream of the ECM can also cause this code: ATD harness 10-pin connector, VIH 31-pin connector, and MCM 120-pin connector.
7. DPF inlet pressure sensor.
8. DPF inlet pressure sensor harness/connector