P24F6
Exhaust Aftertreatment Fuel Air Purge Valve Stuck Open
On systems that inject HC dosing fuel or AIR-assisted reductant into the aftertreatment, a purge valve clears the line after each dosing event. The ECM detects the valve stuck open — pressure or flow does not build up against a closed valve, so the dosing line cannot be charged. Common on diesel HC-doser hardware (DPF regen support).
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Mechanically stuck open valve from soot or cokingCommon
- Broken return springPossible
- Carbon or debris buildup preventing free movementLess likely
Parts involved
- Aftertreatment Purge Valve
- Dosing Line
P24F6 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.