P24B7 code meaning
Particulate Matter Sensor Heater Resistance
Powertrain system Generic code P24xx codes Check engine light
What P24B7 means
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.
P24B7 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P24B7
- Malfunction indicator lamp on
- Sensor regeneration may stay incomplete
Common causes of P24B7
- Most likelyHeater track aged, resistance drifted
- PossibleCorroded connector adding resistance
- Less likelyWrong sensor temperature distorting the expected value
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Particulate matter sensor heater
What each part of P24B7 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| B7 | The exact fault in that area. |
What to do next
- Note P24B7 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P24B7
What does P24B7 mean?
P24B7 means "Particulate Matter Sensor Heater Resistance". P24B7 concerns the resistance of the heater element in the particulate matter sensor, which drifts as the platinum track ages. It is a generic code, so it means the same on every make.
Is it safe to drive with P24B7?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P24B7 fail an emissions test?
Yes, it can. P24B7 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P24B7 to fix?
Difficulty: medium. A typical repair takes 0.5 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P24B7 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.