P0471: Exhaust Pressure Sensor "A" Circuit Range/Performance

P0471 means the signal from exhaust pressure sensor "A" is electrically present but does not make sense: it does not match what the engine computer expects for the engine speed and load, or it does not change when it should. What sensor "A" measures depends on the engine: on many diesels it is an exhaust back pressure sensor before the turbo or before the particulate filter, and on many Volkswagen group TDIs the sensor Volkswagen calls exhaust pressure sensor 1 is the DPF differential pressure sensor, the part that tells the engine how full of soot the filter is. The usual causes are a blocked, split or disconnected sensing pipe or hose, a wrong or failing sensor, or an exhaust or boost leak. A genuinely blocked particulate filter normally sets its own codes, such as P2463 or P244B.

P0471 is a emissions-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P0471 and illuminates the check engine light.

If your vehicle has triggered P0471, you may notice one or more of these symptoms:

• Check engine light on
• Often no change in how the car drives at first
• DPF warning light on some models, sometimes appearing later because regeneration has stopped or is running too often
• Reduced power or limp mode on some vehicles
• Higher fuel consumption if regeneration runs more often than it should
• P0470, or a DPF pressure code such as P2453, stored alongside on some cars

Here are the most common causes of P0471:

Generally yes, for short-term driving. Driveable in the short term, and the car often feels normal at first. Do not leave it for weeks: without a trustworthy exhaust pressure signal the engine computer may suspend particulate filter regeneration or fall back on an estimate, and some cars limit power. A filter that goes too long without regenerating can block, which turns a sensor, hose or wiring repair into a DPF clean or replacement.

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.

Repair costs for P0471 vary depending on the root cause and your vehicle. Here are typical estimates:

P0471 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

These codes are often seen alongside P0471 or indicate related issues: