P2459 Diesel particulate filter regeneration frequency (bank 1)
What P2459 means
A diesel particulate filter (DPF) collects soot and burns it off periodically in a process called regeneration. P2459 means the engine computer has counted more regenerations in a given distance than it expects. Either the engine is producing too much soot, or the computer is wrongly calculating how full the filter is.
P2459 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Medium
- Typical repair cost
- 100–800 €
- Workshop time
- 1–6 h
- Repair difficulty
- Medium
- DIY possible
- No
- Check engine light
- Yes
- Affects emissions test
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Check engine or DPF warning light on
- Cooling fan running after the engine is switched off
- Higher idle speed or fuel consumption during frequent regenerations
- Rising engine oil level from fuel dilution
Common causes
- Mostly short trips, so regenerations are interrupted before they finish
- Faulty DPF differential pressure sensor or blocked sensor pipes
- EGR valve stuck open or leaking, increasing soot
- Worn or leaking injectors producing excess smoke
- Boost leak or dirty air filter causing a rich mixture
Can I keep driving with P2459?
You can drive, but have it checked within one or two weeks. A longer motorway drive can help the filter clean itself; ignoring the code can lead to a blocked DPF and limp mode.
What to check first
- Check the DPF soot load, differential pressure and regeneration history with a scan tool
- Inspect the differential pressure sensor pipes for cracks, blockage or swapped connections
- Check the EGR valve, boost system and injectors for faults that raise soot output
- Check the engine oil level for dilution and change the oil if it is above the maximum mark
Related codes
- P2463 Diesel particulate filter restriction, soot accumulation (bank 1)
- P2418 EVAP system switching valve control circuit/open
- P2400 EVAP leak detection pump control circuit/open
- P22FB NOx sensor performance, sensing element (bank 1 sensor 1)
- P261A Coolant pump B control circuit/open
- P2293 Fuel pressure regulator 2 (B) performance
- P2291 Injector control pressure too low during cranking
- P2635 Fuel pump A low flow/performance
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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