P24B0: particulate sensor electrode response is too small

P24B0 is described as particulate-matter sensor circuit low. The actual GM test compares electrode current at two temperature setpoints during the sensor's regeneration phase. It is intended to detect an open electrode signal or a cracked electrode, rather than simply low measured soot in the exhaust.

Temperature-dependent evidence

The current difference between the two setpoints is compared with a threshold printed as 1.30. The row does not give a clear unit or a fault counter, so that number cannot safely become an external current-test specification or a promised detection time.

The sensor must be commanded into regeneration, actually be in that phase and have electrode-current measurement enabled. Its bus relay, electrical status, communication and control-unit transmission must be healthy. Reporting is Type B, two trips.

What changes the next check

A clean-exhaust particulate reading during ordinary measurement does not test this temperature-dependent electrode response. Verify the sensor's own regeneration state and both current observations, where supported, before interpreting the result. Also distinguish sensor regeneration from regeneration of the vehicle's particulate filter; they are different operating events.

After diagnosis, confirmation requires the qualified electrode test to complete. The source's listed open or cracked mechanisms are diagnostic possibilities, not proof of which occurred, and the table supplies no safe disassembly or repair procedure for the sensor element.

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 1492.