Powertrain, generic (extended)

P24B7 Particulate Matter Sensor Heater Resistance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P24B7 concerns the resistance of the heater element in the particulate matter sensor, which drifts as the platinum track ages. Ford's 2023 diesel summary measures it once per drive right after key-on, with the sensor between -30 and 150 °C, and sets the code if resistance leaves 1.06 to 2.93 Ω at the cold end or 1.81 to 4.12 Ω at the warm end. GM's 14OBDG04 table runs a similar heater self-test after power-up and treats a calculated resistance above roughly 2.93 to 4.13 Ω as an aged heater, Type B. An out-of-range heater may still switch, but it cannot reliably reach the temperature for burning off soot. P24B3, P24B5 and P24B6 are circuit faults; P24D1 shows the effect when regeneration does not finish.

Likely causes

Heater track aged, resistance drifted
Corroded connector adding resistance
Wrong sensor temperature distorting the expected value

Symptoms

  • Malfunction indicator lamp on
  • Sensor regeneration may stay incomplete

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 heater

Related codes

P24B3P24B4P24B5P24B6P24D1

References: fordservicecontent.com, gsi.ext.gm.com.