OBD-II · Engine and powertrain (P)
P2459
DPF regeneration frequency bank 1
What it means
The DPF is regenerating more often than the engine computer expects. Either the engine makes too much soot, the soot estimate is wrong, or the filter is full of ash.
Symptoms
- frequent regenerations (fan after switch-off, higher idle, hot smell)
- higher fuel consumption
- rising oil level from fuel dilution
- engine warning light
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | engine producing excess soot (worn or leaking injectors, boost leak, EGR stuck open, dirty air-mass meter) |
| 02 | faulty DPF pressure sensor or hoses giving a false soot reading |
| 03 | high ash load |
| 04 | short trips interrupting regenerations so they restart often |
What to check, step by step
- 01Read regeneration history, soot and ash load.
- 02Check the pressure sensor and hoses (engine off reading near zero).
- 03Check air-mass meter readings, boost pressure and EGR operation for sources of excess soot.
- 04Check injector correction/balance values.
- 05Check the oil level and change oil if diluted with diesel.