Powertrain, generic (extended)

P24FC Particulate Matter Sensor Heater Control Circuit Driver Current/Temperature Too High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P24FC concerns the output stage that powers the heater of the particulate matter sensor: the driver reports excessive current or an internal temperature past its limit, which suggests a heater with shorted turns or too little resistance, or an overheating sensor electronics unit. On heavy trucks this sensor works as a self-diagnosing device after the SCR catalyst and reports over J1939. Volvo and Mack list P24FC00 in two editions of their PM sensor diagnosis guide for US14+OBD16 engines onward among the codes that justify replacing the sensor, whereas supply-voltage and communication codes point elsewhere. No public threshold exists. P24B5/P24B6 are plain heater circuit shorts, P24B7 the heater resistance. A sensor that cannot heat cannot burn off soot, so filter monitoring stops.

Likely causes

Internal failure of the smart PM sensor (heater or electronics)
Water ingress cracking the ceramic element or shorting the heater
Unusually high exhaust temperature at the sensor, e.g. during repeated regenerations

Symptoms

  • Warning lamp
  • No soot reading from the PM sensor, DPF monitoring not completed

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€250–1,100
Time0.3–1.5 h

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

Parts involved

particulate matter sensor heaterheater driver

Related codes

P24B3P24B5P24B6P24B7P24D1

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