P2452: particulate-filter pressure sensor offset is implausible

Although P2452 has a generic pressure-sensor circuit title, this GM entry is an offset-rationality monitor. With the engine stopped and no flow, expected filter differential pressure is zero. The controller checks whether the learned sensor offset is close enough to its nominal value.

The quantity being compared

The table prints a nominal raw offset of 4.71 and fails when the absolute offset difference exceeds 2.20%. These are raw-signal quantities; they should not be reinterpreted as kilopascals. Offset learning must complete, pipe-temperature qualification must be valid and the result must not already have been reported.

Electrical, stuck-signal, quick-change, temperature-signal and engine-off-timer faults can block the assessment. The row specifies no further debounce after the qualified comparison, a 12.5 ms task and Type A, one-trip reporting.

Why running pressure is not enough

A sensor can respond to exhaust flow yet retain an incorrect baseline. A plausible running value therefore does not independently pass this no-flow test. Confirm the engine-off and learning states, and distinguish an incomplete learning event from an actual failed offset comparison.

For verification, use the applicable service procedure to complete the qualified offset assessment. The summary does not authorize blindly resetting an offset to conceal a physical sensor or pressure-path problem, and it provides no universal replacement decision.

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 829.