Powertrain, generic (extended)

P24AF Particulate Matter Sensor Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

Sensor element aged or glazed, no longer responding
Sensor heater weak so the regeneration temperature is not reached
Element cracked by condensate after cold start

Symptoms

  • Malfunction indicator lamp on
  • Often no change in driveability

Repair estimate

DifficultyMediumDIY possible
Parts and labour€150–700
Time0.5–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

particulate matter sensor

Related codes

P24AEP24B0P24B1P24B3P2002

References: fordservicecontent.com, static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu.