P2002: the particulate filter is not cleaning properly

Book a check soon

The car measures the pressure drop across the particulate filter and finds it is not cleaning as expected. First drive an uninterrupted 20 to 30 minutes at 40 to 50 mph, about 60 to 80 km/h, and see whether the code clears.

Can you keep driving?

Yes, and that is often exactly what solves it.

Cutaway particulate filter, one half clean and the other half clogged with soot

What the code means

This is a measurement of the result, not of the cause. The filter may be more blocked than an ordinary regeneration can handle, or the cause may lie somewhere else.

How the filter cleans itself

The filter burns itself clean in a regeneration, and it only cleans itself at speed. A lot of short trips means it never burns clean, and switching the engine off in the middle of a regeneration interrupts it.

A car on an open road through a valley at dusk
The filter only cleans itself at speed.

Common causes

  • A lot of short-trip driving, so the filter never burns clean
  • Interrupted regenerations
  • A faulty pressure sensor or pressure hose

What to do now

  1. Take an uninterrupted drive at a steady speed on an open road.
  2. Try not to switch the engine off in the middle of a regeneration.
  3. If the code returns after two or three such drives, book an appointment.
A car driving along a motorway at sunset
A steady 20 to 30 minute drive clears this more often than a workshop does.

What people often get wrong

Parking the car when the warning appears. The filter only cleans itself at speed, so the opposite of that instinct is correct.

When the car must go to a workshop

If the code returns after two or three drives, it needs a forced regeneration, which costs an hour or two of labour. That is far cheaper than a new filter.

Read next

This page is general information and does not replace a professional assessment. Symbols, codes and behaviour vary between makes. Always check the handbook for your own car.

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