P24AF code meaning
Particulate Matter Sensor Circuit Range/Performance
Powertrain system Generic code P24xx codes Check engine light
What P24AF means
P24AF tests whether the particulate matter sensor behaves plausibly while it burns itself clean. During that heated phase the electrodes must show a small but definite current, and the heater must change the signal in an expected way. Ford's 2023 diesel summary sets P24AF when the current during sensor regeneration at 770 to 800 °C stays below 0.094 µA, judged over 120 s. VW's 2014 Touareg list uses the code when the accumulated change in heater voltage is no more than 0.25 V. A sensor that no longer reacts cannot detect a cracked or removed filter, which is why CARB requires this check. GM handled P24AF together with P24AE on 2014 and 2015 Cruze diesels under special coverage 16018. P24AE is the electrode circuit fault, P24B3 the heater circuit.
P24AF at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P24AF
- Malfunction indicator lamp on
- Often no change in driveability
Common causes of P24AF
- Most likelySensor element aged or glazed, no longer responding
- PossibleSensor heater weak so the regeneration temperature is not reached
- PossibleElement cracked by condensate after cold start
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Particulate matter sensor
What each part of P24AF 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). |
| AF | The exact fault in that area. |
What to do next
- Note P24AF 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 P24AF
What does P24AF mean?
P24AF means "Particulate Matter Sensor Circuit Range/Performance". P24AF tests whether the particulate matter sensor behaves plausibly while it burns itself clean. It is a generic code, so it means the same on every make.
Is it safe to drive with P24AF?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P24AF fail an emissions test?
Yes, it can. P24AF 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 P24AF to fix?
Difficulty: medium. A typical repair takes 0.5 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P24AF 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.