DPF fault codes and what each one needs
P2002 means the particulate filter's efficiency is below its threshold, P2463 means soot has built up, and P242F means ash has. A clean often helps with soot and sometimes with ash, but not with a damaged filter or a faulty sensor. The table shows what each code usually needs.
A DPF code is a clue, not a verdict. Soot codes usually respond to a clean and a regeneration. Ash and efficiency codes need the filter looked at. Pressure sensor codes point at the sensor or its wiring first. Makers word some codes differently, so check yours.
Which DPF codes mean a blocked filter, and will a clean fix them?
These are the generic OBD-II titles. Your maker's manual has the final wording for your car.
| Code | Generic meaning | Common causes | Does a clean help? | What else to check |
|---|---|---|---|---|
| P2002 | DPF efficiency below threshold | Damaged or cracked filter, filter removed, sensor reading wrongly | Only if the filter is intact | Filter condition, sensors |
| P2463 | DPF restriction, soot accumulation | Failed regenerations, short trips, excess soot from EGR or fuel faults | Often yes | The cause of the soot |
| P242F | DPF restriction, ash accumulation | Ash left after many regenerations, oil use | Depends on the filter. Regeneration won't burn ash | Off-car cleaning may be needed |
| P244A / P244B | Differential pressure too low / too high | Sensor, pipework, a clogged or missing filter | Only if the filter is the cause | Sensor and pipe checks first |
| P2458 / P2459 | Regeneration duration / frequency | Regeneration cycles too long or too often | Sometimes | What is loading the filter so quickly |
| P2452 to P2455 | Pressure sensor circuit family | Sensor, wiring, connector | No | Sensor and circuit tests |
The AA says ash can't be removed on the car, which is why P242F is the awkward one. The soot-based codes are where an on-car clean and forced regeneration earn their keep.
Is it the DPF or the pressure sensor?
The differential pressure sensor tells the engine computer how loaded the filter is. If the sensor is wrong, the car can act as though the filter is blocked when it isn't, or the other way round. One maker's workshop manual for a Vauxhall 1.7 diesel lists P2452 as sensor performance, P2454 as low voltage and P2455 as high voltage, and diagnoses them by testing the sensor circuits first. Other makers word the family differently, which is why generic tables are only a starting point.
That's why we scan and read live data before cleaning. Tom G. wrote that EngiClean found a duff DPF sensor on a Renault Master camper and replaced it before the clean. Martin rang about a blocked filter, and the diagnosis found an EGR valve problem. Both are customers' accounts of their own cars, and the pre-clean scan is how we avoid cleaning a filter that wasn't the fault. Details of what the visit costs are on the cost page.
Can I clear a DPF code myself?
You can wipe a code with a basic scanner. It will come back if the cause is still there, and a warning light that is on or malfunctioning at the MOT is a Major defect under the MOT inspection manual. The manual also lists visible exhaust smoke on a DPF-fitted vehicle as Major.
Clearing the code also removes the evidence a technician needs. We read the codes first, then clear them after the clean and take post-clean readings. One customer says the pre and post scans were insightful, which is why we record both. If a code returns within days, ring us and we'll look at what is feeding it.
Which codes need more than a clean?
- P2002 if the scan suggests the filter itself is damaged. The cleaning versus replacement page explains the decision.
- Persistent sensor codes until the sensor, pipes and wiring are checked.
- P242F when the filter holds a lot of ash.
- Regeneration codes that return, which suggest something is overloading the filter.
If you want to see how a regeneration fits in, read about forced regeneration.
What does P20EE mean?
P20EE is an SCR (AdBlue) code, not a DPF code. It relates to the NOx catalyst efficiency, so a DPF clean won't clear it. If your car shows it alongside a filter code, treat them as separate faults. Our warning light page covers what to do when the filter is the issue.
From our customers
'Check injection' warning on Renault Master camper van. EngiClean diagnosed a duff DPF sensor, which they replaced after getting one locally
Tom G., Google review, August 2026Called regarding a blocked dpf but after a diagnosis it was a egr valve problem.
Martin, Google review, October 2026
Rated 5.0 from more than 440 Google reviews. Read them on Google.
Common questions
- What does P2002 mean?
- P2002 is the generic code for diesel particulate filter efficiency below threshold. It points at the filter or the sensors that monitor it. Common causes include a cracked, damaged or removed filter and a sensor reading wrongly. A clean helps only if the filter is intact, so the scan comes first.
- Can I clear a DPF code myself?
- You can with a scanner, but it will return if the cause is still there. A warning light that is lit or malfunctioning at an MOT is a major defect. We clear codes after a clean and take post-clean readings, so you can see the state of the filter afterwards.
- Will a DPF clean fix P2463?
- P2463 is the soot accumulation code, so a chemical clean and regeneration is the sensible first step when the filter is intact. If the code returns quickly, check what is making excess soot, such as the EGR or fuel system. Cleaning treats the filter, not the cause.
- Is it the DPF or the pressure sensor?
- Read live data to tell. The pressure sensor reports how loaded the filter is, so a faulty one can mimic a blocked filter. A circuit or voltage fault code points to the sensor first. We scan before cleaning so you don't pay to clean a filter that wasn't the fault.
Sources
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