P0470
PowertrainExhaust Pressure Sensor Malfunction
The ECU watches the exhaust pressure sensor, which is the little sensor that tells it how much back pressure is building up in the exhaust, and it sets P0470 when that signal stops making sense against everything else it's seeing. For you, that usually means the warning light comes on and the car feels a bit flat. This one shows up most on diesels, where the sensor is part of the DPF management system, and a blocked sensing tube is a far more common cause than a dead sensor.
ⓘ Information only. This page provides general educational information about fault code P0470. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0470 mean?
P0470 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Exhaust Pressure Sensor Malfunction.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine warning light on, sometimes with no obvious change in how the car drives
- • Down on power, particularly noticeable when you put your foot down on the motorway
- • Worse fuel economy than you're used to
- • On diesels, the DPF regeneration cycle fails or won't start at all
- • Limp mode on some vehicles, leaving you restricted to low revs and modest speed
- • Turbocharged cars can feel laggy or slow to build boost
Possible causes
Causes commonly associated with P0470, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Blocked or carbon-clogged sensing tube between the sensor and the exhaust. This is the first thing to suspect on a diesel, the soot bungs up the narrow pipe long before the sensor itself dies
- 2. Faulty exhaust back pressure sensor, common once the part has had years of heat and vibration
- 3. Damaged, corroded, or loose wiring and connectors in the sensor circuit, often where the loom runs near the hot exhaust
- 4. Short or open circuit in the sensor harness
- 5. An exhaust leak upstream of the sensor throwing off the pressure reading
- 6. EGR system problems on some vehicles, which upset the pressure the sensor is trying to measure
- 7. A failed PCM, but that's rare and only worth considering once everything else checks out
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Read all stored codes and note any siblings like P0471 through P0474, because they often point straight at whether you're chasing a circuit fault or a range/performance fault
- 2. Pull the sensing tube and check it for soot blockage. Try blowing through it, and clear any carbon with a length of wire. On a sooted-up diesel this alone fixes a fair number of P0470s
- 3. Inspect the wiring, plug, and pins for corrosion, chafing, or a loose connection, then clean or repair what you find
- 4. Back-probe the circuit with a multimeter. You want roughly 5V on the reference wire, a good ground, and a clean signal wire with no breaks
- 5. Compare the exhaust pressure sensor reading on a scan tool against MAP and barometric pressure. With the engine off they should all read close to atmospheric, and a sensor that's wildly out has either failed or has a blocked tube
- 6. If the tube is clear, the wiring is sound, and the readings are still off, fit a new sensor and clear the code
Common questions about P0470
Should I save money with a cheap sensor off eBay or buy the proper one? +
For the sensor itself, a quality aftermarket part from a known brand like Bosch or Delphi is fine and a lot cheaper than dealer prices. Where you want to be careful is the no-name budget sensors, which can read slightly off and set the code straight back, leaving you out of pocket and no further forward. Before you spend anything though, clean that sensing tube. People bin perfectly good sensors all the time when the real problem was a soot-blocked pipe.
Is it alright to keep driving with this on? +
For short trips to get to a garage, usually yes, though you may have less power and be drinking more fuel. The catch is on diesels. If the fault is stopping the DPF from regenerating, soot keeps building with nowhere to go, and on some vans you'll eventually get a countdown warning that ends in a no-start or a forced limp mode. Don't sit on it for weeks if you've got a DPF, sort it before the filter clogs solid and turns a cheap job into a very expensive one.
Is this going to be an MOT problem? +
The code on its own isn't a fail, but if the engine warning light is glowing on the dash when the tester looks at it, that's a fail on the warning light check. On a diesel there's also the emissions side. If the fault is messing with DPF function and the exhaust is sooting up, you risk failing the smoke test too. Fix the cause, clear the light, drive a few cycles to make sure it stays off, then book the test.
What's the damage to put it right? +
Depends entirely on what's actually wrong. If it's just a blocked sensing tube cleaned out during a diagnostic visit, you're looking at a low two-figure bill. A new sensor fitted usually lands in the low-to-mid three-figure range once you add labour. Wiring repairs or EGR work can push it higher than that. An independent garage will nearly always come in cheaper than a main dealer, and bear in mind diesels with awkward exhaust access can rack up more labour time than the part cost suggests.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →