P24D1: particulate sensor regeneration does not achieve its thermal goal

P24D1 concerns incomplete regeneration of the particulate-matter sensor, not automatically incomplete regeneration of the vehicle's DPF. The source associates it with degraded sensor-heater performance and evaluates electrode temperature during the sensor's steady regeneration state.

Temperature, power and state transition

The row references 725°C minus a 10°C allowance, a consecutive-time comparison and a power-demand-to-available-power ratio. Its time inequality is not sufficiently clear to prescribe an exact temperature-hold test. The supported interpretation is that thermal performance is assessed with available heating power and sensor state taken into account.

Valid voltage, relay operation, communication and sensor electrical status are required. Exhaust volume, temperature and pressure estimates must be valid. The continuation requires transition from sensor regeneration into measurement, with no control-unit transmission fault. Reporting is Type B, two trips, with no additional debounce listed.

Useful diagnostic decisions

Identify which regeneration event failed before selecting a procedure. A commanded DPF regeneration does not by itself prove that the particulate sensor completed its separate thermal cycle. Also establish whether insufficient available power or invalid estimates prevented qualification.

Verification needs the eligible sensor regeneration and transition to measurement, followed by the actual diagnostic result. The source ambiguity means a vehicle-specific service procedure is necessary; the code alone does not justify direct heater energization or sensor replacement.

Source and application limits

This explanation covers the cited 2025 GM monitor. Confirm the vehicle and calibration in its service information before applying these limits; inclusion in this file does not establish model compatibility. GM diagnostic parameters, PDF page 1500. GM diagnostic parameters, PDF page 1501.