P0472
PowertrainExhaust Pressure Sensor Low
The exhaust pressure sensor measures the back-pressure in your exhaust, mainly to tell the ECU how full the diesel particulate filter is and when to run a regeneration. P0472 means the ECU is seeing a voltage from that sensor circuit that's lower than it should ever be, so it no longer trusts the reading. With a dud signal the engine can't manage the DPF properly, and on most diesels that ends in lost power and a warning light. This is overwhelmingly a diesel code, common on the likes of Ford 1.6/2.0 TDCi, VAG 1.9/2.0 TDI and PSA HDi engines.
ⓘ Information only. This page provides general educational information about fault code P0472. 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 P0472 mean?
P0472 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Exhaust Pressure Sensor Low.
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, usually the first thing you'll notice
- • Drop in power, often with the car dropping into limp mode under acceleration
- • DPF regeneration won't run or fails to complete, and the DPF light may come on too
- • Poorer fuel economy as the engine compensates
- • Rough or hesitant pull-away from cold
- • Occasional stalling or hard starting if the fault is severe
Possible causes
Causes commonly associated with P0472, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Failed exhaust pressure sensor, the usual culprit. They sit in a hot, dirty part of the car and the internals give up over time
- 2. Corroded or loose connector at the sensor, very common where the plug picks up road salt and damp underneath
- 3. Blocked or split pressure tube. The little metal or rubber pipes that feed exhaust gas to the sensor soot up or crack, which throws the reading off
- 4. Damaged wiring in the harness, chafed through or melted where it runs near the hot exhaust
- 5. Short to ground in the signal wire pulling the voltage down to near zero, which is exactly what this code describes
- 6. Heavily clogged DPF skewing the pressure picture, though that more often sets a separate DPF code
- 7. Faulty ECM or a calibration issue, rare and only after 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 live data and look at the actual sensor voltage with the ignition on. P0472 means it's reading low, often pinned near zero, which points at a short or a dead sensor rather than a marginal one
- 2. Get under the car and unplug the sensor connector. Check for green corrosion, bent pins and damp. A clean and reseat fixes a fair few of these before you spend a penny
- 3. Pull the pressure tubes off and check they're clear and not split. A blocked or cracked pipe gives the sensor nonsense to measure
- 4. Test the 5V supply at the sensor with a multimeter, ignition on. No supply or a low reading sends you back up the wiring towards the ECM
- 5. Back-probe the signal wire and compare voltage at the sensor against the ECM pin to find a break or short between the two
- 6. If supply and wiring are good and the tubes are clear, the sensor itself is the likely fault. Replace it and clear the code
Common questions about P0472
Can I keep driving with a P0472 showing? +
For a short hop home or to the garage, yes. The danger is that with a duff exhaust pressure signal the car can't manage DPF regenerations, so the filter keeps loading with soot and never burns it off. Drive it like that for weeks and you risk turning a £150 sensor job into a blocked DPF costing several hundred to clean or replace. If it's already dropped into limp mode, get it looked at before you tackle a long motorway run.
Is this going to fail my MOT? +
The code on its own isn't a fail, but if the engine management light is lit when the tester plugs in or eyeballs the dash, that's a fail on the emissions and warning lamp check. Diesels also get a visible smoke test, and a car that can't regenerate its DPF often smokes more than it should. Sort the fault, clear the light, and let it run a few drive cycles before you book the test.
What's it likely to cost to put right? +
A connector clean or a blocked tube is cheap, often under £60 of labour at an independent if there's no part needed. A new exhaust pressure sensor fitted usually lands around £80 to £180 depending on the engine and how buried it is. Wiring repairs or diagnostic time push it higher. A main dealer will charge noticeably more for the same work, so a decent independent diesel specialist is the sensible call unless the car's still under warranty.
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 →