P2002 fault code: low DPF filtering efficiency
Plain-language definition
Particulate Filter Efficiency Below Threshold Bank 1
What does it mean?
The particulate filter (DPF) is a filter found mostly on diesel cars; it traps soot particles in the exhaust and stops them from getting out. The soot that collects in the filter is cleaned out at intervals by regeneration, that is, by burning it at a high temperature. Since most cars have a single filter, "Bank 1" in the definition refers to this filter.
On many cars the engine computer monitors the filter through the pressure difference between its inlet and outlet (differential pressure sensor); some cars also have a particulate sensor at the filter outlet. A healthy filter puts up some resistance to the exhaust flow; if the measured resistance is lower than expected, or the sensor readings suggest the filter isn't holding the soot, P2002 is stored. Some manufacturers define this code differently.
Often there's no obvious difference while driving; the DPF warning light or the check engine light may come on. If the filter is damaged, you may notice soot at the tailpipe or black smoke when accelerating.
How serious is it?
This is a Warning-level code. If the problem is in the filter, soot particles get out without being filtered; the cause could also be just a sensor or a hose.
Severity is a guide; if the warning light is flashing or you notice symptoms while driving, have the car checked at a workshop.
Common general causes
- Faulty differential pressure sensor
- Cracked, loose or blocked sensor hoses
- Crack in the filter body, or damage from overheating
- Leak at the exhaust connections around the filter
- Faulty particulate sensor (on cars that have one)
- Wiring or connector problems
The list shows general causes; a workshop finds the actual cause on your car with a check.
Definitions by make
Some manufacturers record the same code under their own wording:
- Fiat
- Resistance to air flow in high particulate filter, Plausibility
Related codes
How does it appear in the 2dakika report?
Particulate Filter Efficiency Below Threshold Bank 1
If the code is read as a confirmed (stored) fault, the report shows it with the "Warning" severity; in pending or past records, codes that don't request the warning light and aren't critical appear as "Info". If the engine computer stored them, the conditions when the fault was recorded (engine temperature, rpm, speed) are shown too.
Read this code with the OBD-X1, and clear it from the app after the repair.
Clearing the code doesn't fix the fault; if the problem persists, the code comes back.