P24F6Exhaust Aftertreatment Fuel Air Purge Valve Stuck Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Heavy Volvo and Mack trucks regenerate the particulate filter with an aftertreatment hydrocarbon injector (AHI, the 7th injector) that sprays diesel ahead of the oxidation catalyst; compressed air from the truck supply then blows the line to the nozzle clear. P24F6 means the fuel/air purge valve in the AHI module seems to stay open, so air keeps flowing when it should not. Solution K17696792 (US15 and later, 11, 13 and 16 L engines) lists checks when guided diagnostics finds nothing: 32 psi (221 kPa) at the doser air supply, a dry purge line, the right coalescing air-dryer cartridge and no aerated fuel. For the open case Volvo's AHI guide also replaces the nozzle and cleans the line. Regeneration can fail and soot builds up.
- What you may notice
- Particulate filter regeneration does not complete
- Warning lamp and aftertreatment message on the dash
- Rising soot load and more frequent regeneration requests
- Likely causes
- LikelyOil or water in the purge air from an unsuitable or worn air-dryer cartridge
- PossibleDebris holding the purge valve in the AHI module open
- PossibleDamaged AHI nozzle or leaking fuel/air line toward the nozzle
- RareDoser air supply pressure outside the 221 kPa specification
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €200 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.