P2002
OBD-II Diagnostic Code
Severity: CriticalWhat Does This Error Mean?
P2002 means the Diesel Particulate Filter (DPF) is not capturing soot efficiently. The filter may be clogged, damaged, or the pressure sensors may be faulty. A highway drive at sustained speed can trigger a regeneration to clean the filter.
Affected Models
- All diesel OBD-II vehicles with DPF (2007+)
- Common on VW/Audi TDI, BMW diesel, RAM diesel
Common Causes
- DPF clogged with soot from short trips
- Failed regeneration cycles
- DPF pressure sensor faulty
- DPF substrate cracked or melted
- Exhaust leak before the DPF
How to Fix It
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Take the vehicle for a 20-30 minute highway drive at 2000+ RPM.
Sustained highway driving triggers passive DPF regeneration, burning off accumulated soot. This is the easiest fix if the filter is not severely clogged.
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Use a scan tool to initiate a forced regeneration.
A mechanic can force an active regeneration cycle using a diagnostic scanner. This raises exhaust temperature to burn off soot.
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Check the DPF pressure differential sensor.
Sensors before and after the DPF measure pressure difference. A faulty sensor may report low efficiency when the DPF is actually fine.
Frequently Asked Questions
What is DPF regeneration?
Regeneration burns accumulated soot inside the DPF at high temperature (600°C+). It happens automatically during highway driving or can be forced with a scan tool.
Do short trips cause DPF problems?
Yes. The DPF needs sustained high exhaust temperatures to regenerate. Short city trips never reach these temperatures, causing soot buildup.