OBD code P242F

The particulate filter is restricted by accumulated ash, not only by regenerable soot.

Estimated severity

High

Common symptoms

Limp mode or reduced power
Frequent DPF warnings
High differential pressure
Regenerations that do not solve the problem
Higher fuel consumption and exhaust temperature

Likely causes

High ash load from normal DPF aging
Wrong engine oil specification with excessive ash content
Oil consumption increasing ash accumulation
Long-term urban use with heavy duty cycle
Incorrect DPF load calculation after replacement or cleaning

Recommended checks

1. Read calculated soot and ash load separately if the scanner supports it.
2. Check differential pressure at idle and under load.
3. Review oil specification and possible oil consumption.
4. Do not expect forced regeneration to remove ash.
5. Consider professional DPF cleaning or replacement depending on measured restriction.

What does code P242F mean?

P242F points to DPF restriction caused by ash buildup. Unlike soot, ash does not burn off during normal regeneration. It usually means the filter is nearing its service limit or has suffered from long-term oil consumption, incorrect oil specification or heavy duty cycles.

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