What P0471 means
The exhaust pressure sensor measures the pressure ahead of the turbine or in the manifold (Ford: turbine upstream pressure, Cummins: exhaust manifold pressure, older Ford diesels: EBP).
How the engine computer detects it
The module uses it to calculate EGR flow, to control the variable turbine and engine braking, and to protect against overpressure. P0471 is the plausibility check of sensor A. Ford diesels compare it with ambient pressure with the engine off (at least 10 s stopped); a deviation above 15 kPa (2.2 psi) sets the code, including a sensor stuck mid-range. Ford gasoline engines check it during the EGR monitor. FCA notes for Cummins diesels that P0471 often comes from real back pressure of a clogged particulate filter – then the sensor must not be replaced. Ford bulletins cover a sensor replacement on the 2.7 EcoBoost and coked sensing tubes on the 6.0 diesel.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Check engine light on
- EGR and turbo control on a substitute value, possibly reduced power
- Exhaust brake or warm-up flap without function
Common causes
- Sensor drifting or faulty Most likely
- Sensing tube or hose blocked or coked Most likely
- Real high back pressure from a clogged particulate filter or catalyst Possible
- Leaking sensing tube or exhaust leak ahead of the sensor Less likely
How to diagnose P0471
- Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
- Inspect the parts involved: exhaust pressure sensor a, sensor wiring, engine control module.
- Work through the causes above from most to least likely, cheapest checks first.
- Clear the code and drive a full drive cycle to confirm the repair held.
Vehicles that report P0471 most
| Vehicle | Years | Reports | Share | Median miles |
|---|---|---|---|---|
| Kia K5 | 2021–2022 | 3 | — |
Counts of owner complaints to the NHTSA that mention P0471 (11 in total), not failure rates: popular models get more complaints simply because more of them are on the road. Models with fewer than 3 complaints are left out.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 4
- Auxiliary emission controls
- 71
- Specific fault
Questions drivers ask
Can I drive with code P0471?
Drive gently and only as far as you need to. The engine computer may limit power to protect the engine, so avoid highways and heavy traffic until it's fixed. If the check engine light starts flashing, pull over.
Will my car pass an emissions inspection with P0471?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
Will P0471 clear by itself?
The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.
Can I fix P0471 myself?
Often yes, with an OBD-II scanner and basic tools. Difficulty: medium. Start with the cheapest checks before replacing expensive parts.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.