P24C7: particulate sensor temperature disagrees with its model

P24C7 is a temperature-performance diagnosis for the particulate sensor. It compares electrode temperature with a modeled temperature and fails when the magnitude of the difference exceeds 100°C. The source lists removal from the exhaust, temperature-sensor damage and parasitic harness resistance as detectable mechanisms, without proving any one from the code alone.

A heater-off comparison

The engine must run, the sensor must be in measurement status and its heater must not be commanded. Valid exhaust-temperature and flow estimates, ambient inputs and vehicle-speed information qualify the model. The continuation adds post-regeneration and thermal-separation conditions. This is not the same test as heater performance during sensor regeneration.

The monitor counts 250 failures out of 255 samples at 100 ms intervals, with Type B, two-trip reporting. Relay, communication and sensor electrical faults are also exclusions.

What to compare

Retain measured electrode temperature, modeled temperature and heater state together. A disagreement observed while the heater is deliberately active does not reproduce this monitor. Equally, an invalid model cannot provide a trustworthy reference for condemning the sensor.

Verification requires a completed qualified comparison after the required sensor-state transitions. Some continuation units are unclear, so this summary is not a universal thermal test procedure. Use the actual calibration's instructions to assess the listed mechanisms and confirm the repair.

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 1496. GM diagnostic parameters, PDF page 1497. GM diagnostic parameters, PDF page 1498.