P242FPowertrain
Powertrain · SAE
Diesel Particulate Filter (DPF) — Ash Accumulation/Restriction
Meaning
The ECU detects a particulate filter restriction caused by ash accumulation that can no longer be removed by regeneration. Ash is the non-combustible residue that builds up in the DPF over time and reduces its capacity.
Common causes
- Ash-saturated filter at end of service life
- Repeated incomplete regenerations (short trips)
- Non-spec engine oil (high ash content)
- High engine oil consumption
- Inaccurate differential pressure sensors
Symptoms
- Check engine and/or DPF light on
- Power loss or reduced mode
- More frequent and ineffective regenerations
- Increased fuel consumption
Severity
Moderate/serious: ash cannot be regenerated away; specialist cleaning or DPF replacement is needed and should be planned.
What to do
- Read DPF backpressure and estimated ash values
- Check the differential pressure sensors and pipes
- Check oil consumption and the spec of the oil used
- Plan professional cleaning or DPF replacement