OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P24B4

Particulate Matter Sensor Heater Control Circuit Range or Performance

Same as P24B3 with the heater control loop in plausible range yet not matching the heater model. The sensor heater warms the element to operating temperature (~600 °C); without it the lambda sensor stays inactive in closed loop and the ECM cannot trim mixture.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / B4

Possible causes

  • Heater element aged high

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 400–1200 €
  • Estimated time: 1–3 h
  • Component: particulate matter sensor heater
  • MIL / check engine light
  • emissions-relevant

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication