P24B7Particulate Matter Sensor Heater Resistance
- 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
- 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.
- What you may notice
- Malfunction indicator lamp on
- Sensor regeneration may stay incomplete
- Likely causes
- LikelyHeater track aged, resistance drifted
- PossibleCorroded connector adding resistance
- RareWrong sensor temperature distorting the expected value
- 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.