P24AFParticulate Matter Sensor Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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.
- What you may notice
- Malfunction indicator lamp on
- Often no change in driveability
- Likely causes
- 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
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €150 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.