P2455: filter pressure-sensor signal above its electrical ceiling

P2455 evaluates the upper electrical range of the particulate-filter differential-pressure sensor. The raw input fails above 99.80%. The source associates this with an open circuit or short to battery, so the code does not uniquely distinguish those two electrical conditions.

Why “high” is not a blockage diagnosis

The compared value is a raw electrical representation. It is not a pressure threshold demonstrating filter restriction. A high differential-pressure performance result must be considered separately from a signal that has reached its electrical clamp boundary.

Calibration must enable the check, run/crank and ignition state must be valid, diagnostics must not be resetting, and the engine must not be cranking. The controller counts 158 failures out of 200 at a 12.5 ms task rate. The entry is Type A, one trip.

Verification and limits

Retain the raw input state and use the exact circuit procedure to distinguish an open path from an unintended power connection. The table's two possibilities should not be collapsed into an automatic sensor-replacement conclusion. After correction, verify completion of the electrical upper-range check under qualified conditions. A believable converted pressure reading or a cleared code alone does not establish that the raw signal remains valid. Connector identification and test voltages are not supplied here.

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 832.