P2452 to P2455: DPF pressure sensor circuit codes
The P2452 to P2455 family means the differential pressure sensor or its wiring is giving a reading the computer does not believe. Why this is usually not a filter problem, and why the filter must still be measured before it is blamed.
- Urgency
- Routine
- Reads the vehicle
- Your workshop
- Measures the filter
- Us
- Clean from
- ₹6,500
In plain words
P2452 is "Diesel Particulate Filter Pressure Sensor A Circuit", P2453 is the same sensor's range or performance, P2454 is the circuit reading low and P2455 is the circuit reading high. P0471 is the older generic code for the exhaust pressure sensor's range or performance and appears on some vehicles in the same situations. All five are about the sensor and its signal, not about the filter.
The differential pressure sensor is the single instrument the engine computer uses to judge the filter. It reads the pressure before and after the filter through two narrow pipes, and the difference between them is what the soot model, the regeneration logic and the efficiency check all depend on. When the sensor or its pipes fail, every DPF decision the vehicle makes is based on a wrong number, which is why a sensor code so often arrives with a false DPF code beside it.
Usual causes, most common first
- 01A differential pressure line split, perished, blocked with soot or water, or disconnected
- 02A sensor that has drifted with age or heat, reading a pressure that is not there
- 03Corroded or chafed wiring and connectors on the sensor circuit
- 04A sensor that has been contaminated by exhaust condensate drawn back down the line
- 05Less often, a genuinely blocked filter driving the sensor to the top of its range
In this order
Cheapest and least invasive first. Each step rules something out before you spend on the next.
Have your workshop inspect both pressure lines along their full length, and blow them through. This fixes a large share of these codes for the cost of an hour.
Have the sensor's live reading checked at key-on, engine off, where it should read close to zero, and at idle and under load, against the expected range.
Replace the sensor only when the lines are proven good and the reading is still wrong. Replacing it first is the most common wasted spend on this code.
If a DPF restriction code is present alongside the sensor code, do not act on it until the sensor is fixed and the restriction code has been re-checked with a good signal. If it persists, the filter is measured.
What we find when the filter reaches us
Flow and back pressure are measured on arrival, before anything is quoted, and again after cleaning. Both readings go back with the filter.
- Most filters sent to us because of a sensor code flow normally on the bench. The filter was never the fault, and we say so rather than clean something that does not need it.
- A filter that does read as blocked on the bench, with a high-range sensor code, is the exception, and cleaning resolves both.
The symptom checker's view
The same pattern, scored from your answers. Each result links to the service that addresses it.
Asked about this one
No. These codes describe the pressure sensor and its circuit. The filter may be fine, and on most vehicles that reach us with these codes it is. Fix the sensor or its lines first, then re-check for any filter code.
Because the computer uses the sensor to judge the filter. A wrong pressure reading produces a wrong conclusion about soot or efficiency, and that conclusion sets a second code. Once the sensor is fixed, the second code often does not return.
Close to zero with the key on and the engine off, since both sides of the filter are at atmospheric pressure. At idle on a clear filter the reading is small, a few millibar, and it rises with engine load and with the soot in the filter. The exact limits are set per vehicle by the manufacturer, so a single "correct" number does not exist; what matters is the reading against the vehicle's own expected table, and the two sanity checks: zero at key-on, and a reading that rises and falls with load rather than sitting fixed. A sensor that reads well above zero at key-on, or that never changes, is the fault.
Only if the filter is measured and found to be loaded. If the vehicle is at high mileage and the filter is coming off anyway, measuring it is cheap and tells you whether it is worth cleaning now rather than in six months. A filter that flows normally goes back on uncleaned.
Related problems
All problems and codesSend the code and a photograph
A picture of the scanner screen or the dashboard message, the vehicle and mileage, and how it is behaving. You will get a straight answer on whether the filter is the problem, and what it costs to find out.