Diesel Particulate Filter Efficiency Below Threshold (Bank 1)
The diesel particulate filter (DPF) traps soot from diesel engines and burns it off from time to time in a “regeneration”, which needs the exhaust to be very hot. This code means the engine computer thinks the filter isn't working properly. Some makes, such as the VW group, describe it as a “particulate filter malfunction”.
What the car has detected
Using the differential pressure sensor data (the pressure difference before and after the filter), the engine computer has concluded that the filter isn't holding soot as it should, or that the reading doesn't make sense.
You can drive carefully, but the car may fail the inspection and, if the sensor gives false data, regenerations can fail and the filter can fill up. Get it checked soon.
Symptoms
- Engine or DPF warning light on
- More frequent or unfinished regenerations
- Exhaust smoke if the filter is cracked
- Loss of power in some cases
Possible causes
- Faulty or leaking exhaust differential pressure sensor (on some VW group engines, sensors with faulty seals)
- Sensor pipes broken, loose or blocked
- Damaged or cracked particulate filter
- Filter removed or tampered with
Checks for the garage
- Check the differential pressure sensor and its pipes
- Compare the differential pressure in live data with the expected value
- Run a regeneration with diagnostics if appropriate
- Inspect the filter for cracks or damage
Next step
Have the exhaust pressure sensor and its pipes checked first, then the filter itself.
Go to a garage to check the sensor and filter before replacing anything: the filter is expensive and the cause is often the sensor.