P2002 — Diesel Particulate Filter Efficiency Below Threshold (Bank 1) (6.7 Cummins (SCR / DEF))
Diagnostic reference for 6.7 Cummins SCR/DEF 2013–present.
What it means
P2002 is a generic OBD-II DPF efficiency code that applies to this platform; presentation is consistent with generic DPF monitoring.1
Most likely causes
- DPF soot loading / ash accumulation reducing filtration efficiency — DPF efficiency judged by pressure/temperature data is below threshold.1
- Exhaust restriction or abnormal backpressure affecting DPF monitoring — Generic definition: DPF filtering efficiency, judged by pressure/temperature data, is below threshold.1
- Aftertreatment sensor / monitoring data anomaly influencing efficiency calculation — Generic definition: DPF filtering efficiency, judged by pressure/temperature data, is below threshold.1
How to diagnose
- Verify code presence and freeze-frame conditions; confirm P2002 is active on 6.7 Cummins SCR/DEF.
- Review recent regeneration history and driving cycle suitability for passive/active regen.
- Inspect aftertreatment pressure/temperature sensor readings for plausibility vs. expected DPF behavior.
- Check for accompanying aftertreatment codes that may indicate root cause rather than DPF itself.
- Assess DPF differential pressure trend under steady load to evaluate restriction vs. efficiency monitoring logic.
Parts and tools you may need
- OBD-II scan tool with Cummins enhanced data
- Exhaust backpressure / differential pressure gauge
- Thermal imaging or exhaust temperature probe
Rough cost and difficulty
Cost varies by model year, root cause, and labor; DPF service/replacement is high-cost. Diagnosis should isolate monitoring vs. actual hardware fault before parts replacement.
When to see a pro
If limp mode, derate, or repeated P2002 with accompanying SCR/NOx codes, have a qualified diesel technician evaluate aftertreatment system. Do not attempt high-pressure fuel or exhaust system repairs without proper training and safety controls.
Sources
Watch a repair
Third-party videos, not ours — for illustration. Confirm anything against the factory service information for your truck.
Help improve this guide
Own a 6.7 and spotted something wrong or missing? Tell us. This goes straight to the editor — it is not published.