P2003 on Audi: Causes, Symptoms and Fix Cost

The Quick Answer above is the generic definition. What follows is the model-specific detail for the Audi models that log P2003.

Beyond the generic causes listed on the main P2003 page, these are the patterns noted for Audi models:

Follow these steps to pinpoint the root cause of P2003:

1. Read all stored codes and the freeze frame with an OBD2 reader. Note whether P2002 (bank 1), P244A (pressure too low), P244B or P2463 (pressure too high, soot build-up) sit alongside P2003, because they say whether the filter looks empty or full. A generic OBD2 reader can show these codes, the freeze frame and standard live data, but on most cars not the pressure across each filter, the soot load or the regeneration history, and it cannot run a forced regeneration or an adaptation: those need manufacturer-level software or a workshop.
2. Confirm the engine really has two particulate filters. Bank 2 is the cylinder bank that does not contain cylinder 1; on a twin-filter V8 or V12 each bank has its own filter, pressure sensor and temperature sensors. A single-filter diesel should report P2002 instead.
3. Inspect the bank 2 pressure sensor hoses and pipes for splits, melted sections, blockage or a loose end, and check that the upstream and downstream hoses are on the right ports. A hose that no longer sees the pressure ahead of the filter makes the filter look cracked or empty while it is fine.
4. Check the exhaust for leaks between the engine and the bank 2 filter, which also lower the pressure the sensor sees.
5. With manufacturer-level software, compare the pressure across the bank 2 filter with bank 1 at the same engine speed and load. With the hoses and sensor proven good, a much lower bank 2 reading points to a cracked, melted or missing filter; a much higher one points to a loaded filter instead.
6. Look for soot where there should be none: a filter that works leaves the tailpipe and the pipe after it largely clean, and a workshop can hold a clean cloth over the tailpipe while the engine is revved to see whether soot is getting through.
7. A cracked or melted filter has to be replaced; cleaning removes soot and ash but cannot repair the substrate. Before fitting a new one, find what overheated or overloaded the old one (leaking injectors, a faulty exhaust fuel injector, repeatedly interrupted regenerations) and confirm the engine oil meets the low-ash specification, then have any adaptation the engine computer requires done with manufacturer-level software.

Estimated repair costs for P2003 in EUR, compiled across makes. Expect Audi parts and labour towards the upper end of each range.

These codes are often seen alongside P2003 or point to related issues, on any make: