P0471 on Volkswagen: Causes, Symptoms and Fix Cost

The Quick Answer above is the generic definition. What follows is the model-specific detail for the Volkswagen models that log P0471.

Beyond the generic causes listed on the main P0471 page, these are the patterns noted for Volkswagen models:

Follow these steps to pinpoint the root cause of P0471:

1. Read all stored codes and the freeze frame. Note whether P0470 or a DPF code (P2452 to P2455, P244A, P244B or P2463) is stored alongside, and note the engine speed and load when the fault set. A generic OBD2 reader shows this code, its freeze frame and standard live data. A few diesels also report exhaust or DPF pressure on a standard PID, but on most cars the pressure reading, the soot load and the regeneration history need manufacturer-level software, and only that software or a workshop can run a forced regeneration or adapt a new sensor.
2. Find out which sensor is exhaust pressure sensor "A" on your engine: a back pressure sensor near the exhaust manifold or turbo, a sensor before the particulate filter, or on many Volkswagen group TDIs the DPF differential pressure sensor. Check the workshop information for your engine code.
3. With the engine cold, trace the sensing pipes and hoses from the exhaust to the sensor. Look for split, melted, kinked or disconnected hoses, and on a differential sensor check that the two hoses go to the right ports, because swapped hoses give a plausible but wrong reading.
4. Disconnect the pipes and check they are clear. The metal pipes near the exhaust can fill with soot, and blowing through them or clearing them with a wire usually shows a blockage.
5. With manufacturer-level software, compare the pressure reading with the engine off and then at idle and higher revs. With the engine off it should read close to zero, or close to outside air pressure on an absolute sensor, and it should rise smoothly with revs. A reading that is stuck, jumps or is far off at rest points to the sensor.
6. Check for exhaust leaks before the sensing point, and for boost or EGR leaks, which change exhaust flow and pressure.
7. Replace the sensor with the correct part for the engine code if the pipes and hoses are good, run the sensor adaptation if the engine computer asks for one, clear the code and road-test. If the filter is genuinely loaded, a forced regeneration or a clean comes next.

Estimated repair costs for P0471 in EUR, compiled across makes. Volkswagen costs typically sit in the middle of each range.

These codes are often seen alongside P0471 or point to related issues, on any make: