P0472–P047C Exhaust Pressure Sensor A Circuit Low
The voltage on this circuit is sitting near zero. Typically a short to earth, or a sensor that has failed to its low end.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P0472 | Exhaust Pressure Sensor A Circuit Low | Investigate soon |
P047C | Exhaust Pressure Sensor B Circuit Low | Investigate soon |
The definition
P0472: Exhaust Pressure Sensor A Circuit Low.
P0472 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.
What to check first
Cheapest and fastest checks first:
- Unplug the sensor. If the reading jumps to full scale, the wiring is fine and the sensor has failed low.
- Check the sensor's 5V supply and its earth before condemning the sensor itself.
What actually causes this on a VAG
This one is electrical rather than physical - the control unit is seeing the exhaust pressure sensor's signal sitting lower than it should ever go, which usually means it is shorted to earth, has lost its supply, or has failed internally. It is not telling you that exhaust pressure is low; it is telling you the number cannot be believed. On a diesel with a particulate filter the control unit falls back on its modelled soot load, and on many of these engines it will not attempt a filter regeneration while the fault is present.
Most likely causes, in order
- Water or corrosion in the sensor connector. The plug sits low and exposed in a hot, wet area, and damp bridging the pins pulls the signal down. Unclip it and look for green powder, a swollen seal or moisture inside. This is free to check and is a common finding on this code.
- Chafed wiring shorting to earth. Follow the loom from the sensor and check anywhere it crosses a bracket, heat shield or engine mount. Vibration wears the insulation through and the bare wire touches metal. A fault that comes and goes with engine movement is a strong hint.
- Sensor failed internally. Confirm by testing at the plug rather than by swapping parts. With the sensor unplugged and the ignition on, the reference voltage and earth from the control unit side should both be present and steady, and the fault should normally change to the circuit-high version. If the low fault stubbornly stays with the sensor disconnected, the short is in the harness, not the sensor.
Worth knowing: Do not just clear this and carry on driving. While the fault is stored the car will often not attempt a particulate filter regeneration, so soot keeps building with nothing burning it off. A cheap connector or wiring fault left unfixed is exactly how people end up paying for a forced regeneration or a new filter.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P0472 mean?
P0472 means Exhaust Pressure Sensor A Circuit Low. The voltage on this circuit is sitting near zero. Typically a short to earth, or a sensor that has failed to its low end.
Can I drive with P0472?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.