P24F7 code meaning
Exhaust Aftertreatment Fuel Air Purge Valve Stuck Closed
Powertrain system Generic code P24xx codes Check engine light
What P24F7 means
P24F7 is the reverse case of P24F6: the purge valve of the aftertreatment fuel/air system will not open when commanded, so no compressed air reaches the dosing line and the 7th injector after a dosing phase. In Volvo and Mack trucks this valve sits in the AHI dosing block, mounted on the fuel filter housing from model year 2017 and on the engine block side before. Volvo's AHI troubleshooting guide points to the air supply, the module and the fuel/air lines up to the nozzle; contamination carried in with the air or fuel causes most module failures. The joint solution for both purge codes was reissued as KC-401 for trucks from model year 2016 and starts with the 221 kPa air pressure check. Without purging, fuel can coke in the line.
P24F7 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P24F7
- Active regeneration aborted or not started
- Warning lamp with aftertreatment message
- Possible engine derate as soot load climbs
Common causes of P24F7
- Most likelyPurge valve jammed by oil, water or particles from the air system
- PossibleAir supply to the AHI module restricted or below specification
- PossibleCoked or kinked line between AHI module and nozzle
- Less likelyInternal fault of the AHI dosing module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Aftertreatment purge valveDosing line
What each part of P24F7 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| F7 | The exact fault in that area. |
What to do next
- Note P24F7 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P24F7
What does P24F7 mean?
P24F7 means "Exhaust Aftertreatment Fuel Air Purge Valve Stuck Closed". P24F7 is the reverse case of P24F6: the purge valve of the aftertreatment fuel/air system will not open when commanded, so no compressed air reaches the dosing line and the 7th injector after a dosing phase. It is a generic code, so it means the same on every make.
Is it safe to drive with P24F7?
Drive gently and only to a workshop. With P24F7 the car can go into limp mode (reduced power) to protect itself.
Will P24F7 fail an emissions test?
Yes, it can. P24F7 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P24F7 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P24F7 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.